Publications by authors named "I-Feng Lin"

57 Publications

Resting Dead Space Fraction as Related to Clinical Characteristics, Lung Function, and Gas Exchange in Male Patients with Chronic Obstructive Pulmonary Disease.

Int J Gen Med 2021 3;14:169-177. Epub 2021 Feb 3.

Institute of Public Health, National Yang Ming University, Taipei, Taiwan, 11221, Republic of China.

Background: Measures of forced expired volume in one second % predicted (FEV%), residual volume to total lung capacity ratio (RV/TLC) and diffusing capacity for carbon monoxide measurements (DCO) are the standard lung function test for evaluating patients with chronic obstructive pulmonary disease (COPD). The dead space fraction (V/V) has been shown to be a robust marker of gas exchange abnormality. However, the use of V/V has gradually become less common. As V/V measured at rest (V/VR) has been successfully used in non-COPD conditions, it was hypothesized that in COPD the V/VR was more sensitive than the standard lung function test in correlation with clinical characteristics and gas exchange. This study aimed to test the hypothesis and to identify the variables relevant to V/VR.

Methods: A total of 46 male subjects with COPD were enrolled. Clinical characteristics included demographic data, oxygen-cost diagram (OCD), and image studies for pulmonary hypertension. The standard lung function was obtained. To calculate V/V, invasive arterial blood gas and pulmonary gas exchange (PGX) were measured. The variables relevant to V/VR were analyzed by multiple linear regression.

Results: Compared to lung function, V/VR was more frequently and significantly related to smoking, carboxyhemoglobin level, pulmonary hypertension and PCO (all p <0.05) whereas FEV% was more related to lung function test, PO and OCD score. V/VR and FEV% were highly related to resting gas exchange but RV/TLC and DCO% were not. Cigarette consumption, the equivalent for CO output, arterial oxyhemoglobin saturation, and the product of tidal volume and inspiratory duty cycle were identified as the parameters relevant to V/VR with a power of 0.72.

Conclusion: Compared to lung function test, V/VR is more related to clinical characteristics and is a comprehensive marker of resting gas exchange. Further studies are warranted to provide a noninvasive measurement of V/VR.

Registration Number: MOST 106-2314-B-040-025 and CSH-2019-C-30.
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http://dx.doi.org/10.2147/IJGM.S291555DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7868954PMC
February 2021

Applying Machine Learning Models with An Ensemble Approach for Accurate Real-Time Influenza Forecasting in Taiwan: Development and Validation Study.

J Med Internet Res 2020 08 5;22(8):e15394. Epub 2020 Aug 5.

Taiwan Centers for Disease Control, Taipei, Taiwan.

Background: Changeful seasonal influenza activity in subtropical areas such as Taiwan causes problems in epidemic preparedness. The Taiwan Centers for Disease Control has maintained real-time national influenza surveillance systems since 2004. Except for timely monitoring, epidemic forecasting using the national influenza surveillance data can provide pivotal information for public health response.

Objective: We aimed to develop predictive models using machine learning to provide real-time influenza-like illness forecasts.

Methods: Using surveillance data of influenza-like illness visits from emergency departments (from the Real-Time Outbreak and Disease Surveillance System), outpatient departments (from the National Health Insurance database), and the records of patients with severe influenza with complications (from the National Notifiable Disease Surveillance System), we developed 4 machine learning models (autoregressive integrated moving average, random forest, support vector regression, and extreme gradient boosting) to produce weekly influenza-like illness predictions for a given week and 3 subsequent weeks. We established a framework of the machine learning models and used an ensemble approach called stacking to integrate these predictions. We trained the models using historical data from 2008-2014. We evaluated their predictive ability during 2015-2017 for each of the 4-week time periods using Pearson correlation, mean absolute percentage error (MAPE), and hit rate of trend prediction. A dashboard website was built to visualize the forecasts, and the results of real-world implementation of this forecasting framework in 2018 were evaluated using the same metrics.

Results: All models could accurately predict the timing and magnitudes of the seasonal peaks in the then-current week (nowcast) (ρ=0.802-0.965; MAPE: 5.2%-9.2%; hit rate: 0.577-0.756), 1-week (ρ=0.803-0.918; MAPE: 8.3%-11.8%; hit rate: 0.643-0.747), 2-week (ρ=0.783-0.867; MAPE: 10.1%-15.3%; hit rate: 0.669-0.734), and 3-week forecasts (ρ=0.676-0.801; MAPE: 12.0%-18.9%; hit rate: 0.643-0.786), especially the ensemble model. In real-world implementation in 2018, the forecasting performance was still accurate in nowcasts (ρ=0.875-0.969; MAPE: 5.3%-8.0%; hit rate: 0.582-0.782) and remained satisfactory in 3-week forecasts (ρ=0.721-0.908; MAPE: 7.6%-13.5%; hit rate: 0.596-0.904).

Conclusions: This machine learning and ensemble approach can make accurate, real-time influenza-like illness forecasts for a 4-week period, and thus, facilitate decision making.
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http://dx.doi.org/10.2196/15394DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7439145PMC
August 2020

Plasma lipid concentrations and survival in geriatric population: A retrospective cohort study.

Medicine (Baltimore) 2019 Dec;98(49):e18154

Institute of Public Health, National Yang-Ming University.

Plasma lipids in mid-life are important predictors for cardiovascular events and deaths. However, the association between plasma lipid concentrations and mortality in late life is controversial. Recent studies showed that older people with extremely low total cholesterol (TC) have poor survival outcome, but this conclusion was drawn mostly from Western cohorts. Our study investigated association between plasma lipid concentrations and mortality in Taiwanese elderly population.A retrospective cohort study was conducted among the 69,824 elderly people who participated in the Taipei City Geriatric Health Examination between 2006 and 2010, with a mean follow-up of 3.6 years. The measurements of TC, high density lipoprotein (HDL) and triglycerides were obtained from the records of the participants. Low density lipoprotein (LDL) was calculated using Friedewald formula in 69,088 participants. All lipid components were categorized into quartiles. Males and females were analyzed separately using multivariate Cox proportional hazards models.The elderly with the lowest quartile of TC (<175 mg/dL), HDL cholesterol (<43 mg/dL) and LDL cholesterol (<100.4 mg/dL) were at higher risk of all-cause mortality. Older females with the lowest quartile of TC and LDL cholesterol had higher cardiovascular mortality. Older females with the lowest quartile of HDL had higher mortality from cardiovascular and cerebrovascular diseases.We concluded that TC, mostly attributed to LDL cholesterol, was inversely related to all-cause mortality. HDL remained to be protective against both cardiovascular and stroke mortality in older females. The target levels of plasma lipids in people older than 65 years should be different from that in younger adults.
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http://dx.doi.org/10.1097/MD.0000000000018154DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6919530PMC
December 2019

Severe diabetes complications among patients with diabetes with regular follow-up: Does care setting matter?

J Eval Clin Pract 2020 Aug 6;26(4):1212-1219. Epub 2019 Nov 6.

Institute of Public Health, School of Medicine, National Yang-Ming University, No. 115, Sec. 2, Li-Nong Street., Beitou District, Taipei City, 112, Taiwan.

Objective: To investigate diabetes outcomes by long-term trajectories of patients' care settings among diabetes patients with regular follow-up.

Research Design And Methods: This longitudinal population-based cohort study used data from the National Health Insurance Research Database in Taiwan. The trajectories of diabetes care-seeking behaviours among newly diagnosed diabetes patients with regular follow-up were identified using a group-based trajectory model from 2000 to 2004. Severe diabetes complications were assessed for the period 2005-2010. Cox-proportional hazard method with a cumulative incidence function was applied.

Results: Among the diabetes patients with regular follow-up during the first 5 years since diagnosis, 44.5% and 40.6% were persistently cared for in generalized care settings and specialized settings, respectively. Only 14.9% of them had shifted between different levels of care setting during the first 5 years. No significant difference in adverse outcomes was observed between patients who were persistently treated in generalized and specialized care settings. Significantly worse outcomes were observed among patients who shifted from generalized care settings to specialized settings (adjusted hazard ratio [aHR]=3.2, 95% confidence interval [CI]: 1.5, 6.8). In contrast, among the elderly, regular users of generalized care providers had a higher hazard of adverse outcomes than those of specialized care providers (aHR = 3.3, 95% CI: 1.0, 10.7).

Conclusions: Diabetes patients who were persistently treated in generalized care settings had health outcomes comparable to those who were persistently treated in specialized care settings. However, for elderly and less stable patients, regular diabetes care in specialized care settings was preferable.
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http://dx.doi.org/10.1111/jep.13296DOI Listing
August 2020

Investigating the relationships among lung function variables in chronic obstructive pulmonary disease in men.

PeerJ 2019 1;7:e7829. Epub 2019 Oct 1.

Institute of Public Health, National Yang Ming University, Taipei, Taiwan.

Background: In patients with chronic obstructive pulmonary disease (COPD), the independent contributions of individual lung function variables to outcomes may be lower when they are modelled together if they are collinear. In addition, lung volume measurements may not be necessary after spirometry data have been obtained. However, these hypotheses depend on whether forced vital capacity (FVC) can predict total lung capacity (TLC). Moreover, the definitions of hyperinflation and air trapping according to lung function variables overlap and need be clarified. Therefore, the aim of this study was to evaluate the relationships among various lung function parameters to elucidate these issues.

Methods: Demographic data and 26 parameters of full lung function were measured in 94 men with COPD and analyzed using factor and correlation analyses.

Results: Factor analysis revealed five latent factors. Inspiratory capacity (IC)/TLC and residual volume (RV)/TLC were most strongly correlated with all other lung volumes. IC/TLC, RV/TLC, and functional residual capacity (FRC)/TLC were collinear and were potential markers of air trapping, whereas TLC%, FRC%, and RV% were collinear and were potential markers of hyperinflation. RV/TLC >0.4 (or IC/TLC <0.4) was comparable with the ratio of forced expiratory volume in one second (FEV) and FVC <0.7. FVC% and FEV% were poorly correlated with TLC%. The correlation study showed that TLC%, RV/TLC, and FEV% could be used to represent individual latent factors for hyperinflation, air trapping, inspiration, expiration, and obstruction. Combined with diffusion capacity%, these four factors could be used to represent comprehensive lung function.

Conclusions: This study identified collinear relationships among individual lung function variables and thus selecting variables with close relationships for correlation studies should be performed with caution. This study also differentiated variables for air trapping and lung hyperinflation. Lung volume measurements are still required even when spirometry data are available. Four out of 26 lung function variables from individual latent factors could be used to concisely represent lung function.
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http://dx.doi.org/10.7717/peerj.7829DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6777488PMC
October 2019

More Impaired Dynamic Ventilatory Muscle Oxygenation in Congestive Heart Failure than in Chronic Obstructive Pulmonary Disease.

J Clin Med 2019 Oct 7;8(10). Epub 2019 Oct 7.

Department of Pulmonary and Critical Care Medicine, Chiayi Chang-Gung Memorial Hospital, Chang-Gung Medical Foundation, Chiayi 61363, Taiwan.

Patients with chronic obstructive pulmonary disease (COPD) and congestive heart failure (CHF) often have dyspnea. Despite differences in primary organ derangement and similarities in secondary skeletal muscle changes, both patient groups have prominent functional impairment. With similar daily exercise performance in patients with CHF and COPD, we hypothesized that patients with CHF would have worse ventilatory muscle oxygenation than patients with COPD. This study aimed to compare differences in tissue oxygenation and blood capacity between ventilatory muscles and leg muscles and between the two patient groups. Demographic data, lung function, and maximal cardiopulmonary exercise tests were performed in 134 subjects without acute illnesses. Muscle oxygenation and blood capacity were measured using frequency-domain near-infrared spectroscopy (fd-NIRS). We enrolled normal subjects and patients with COPD and CHF. The two patient groups were matched by oxygen-cost diagram scores, New York Heart Association functional classification scores, and modified Medical Research Council scores. COPD was defined as forced expired volume in one second and forced expired vital capacity ratio ≤0.7. CHF was defined as stable heart failure with an ejection fraction ≤49%. The healthy subjects were defined as those with no obvious history of chronic disease. Age, body mass index, cigarette consumption, lung function, and exercise capacity were different across the three groups. Muscle oxygenation and blood capacity were adjusted accordingly. Leg muscles had higher deoxygenation (HHb) and oxygenation (HbO) and lower oxygen saturation (SO) than ventilatory muscles in all participants. The SO of leg muscles was lower than that of ventilatory muscles because SO was calculated as HbO/(HHb+HbO), and the HHb of leg muscles was relatively higher than the HbO of leg muscles. The healthy subjects had higher SO, the patients with COPD had higher HHb, and the patients with CHF had lower HbO in both muscle groups throughout the tests. The patients with CHF had lower SO of ventilatory muscles than the patients with COPD at peak exercise ( < 0.01). We conclud that fd-NIRS can be used to discriminate tissue oxygenation of different musculatures and disease entities. More studies on interventions on ventilatory muscle oxygenation in patients with CHF and COPD are warranted.
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http://dx.doi.org/10.3390/jcm8101641DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6832638PMC
October 2019

Variation in the 11-year trajectories of medical care seeking behaviors in diabetes patients under a single payer system: persisting gaps to be filled.

BMC Health Serv Res 2019 Aug 19;19(1):580. Epub 2019 Aug 19.

Institute of Public Health, School of Medicine, National Yang-Ming University, No.115, Sec. 2, Linong Street, Taipei, Taiwan.

Background: Care-seeking behavior is widely acknowledged to have strong influences on health outcomes among individuals with chronic conditions including diabetes. Despite its dynamic nature, care seeking behavior are often considered as time invariant in most studies. The likelihood of patients changing their regularity and source of chronic care over time is often neglected. This study aimed to determine the long-term trajectories of care-seeking patterns of both care-seeking regularity and health provider choices; and their associated factors among patients with type 2 diabetes under the National Health Insurance (NHI) program in Taiwan.

Methods: We utilized population-based data from the National Health Insurance Research Database (NHIRD) in Taiwan. Three thousand, nine hundred and eighty-seven adult patients with newly diagnosed type 2 diabetes in 1999 were enrolled in the cohort. We assessed their trajectories of regular care visits and sources of diabetes care from 2000 to 2010. A group-based trajectory model was applied.

Results: Seven distinct groups of long-term care-seeking patterns were identified. Only 51.44% of patients with newly diagnosed diabetes had regularly visited their providers over time. Among them, 56.41 and 16.09% had persistently sought care from generalized and specialized providers, respectively. 27.50% had sought care from different levels of providers. Patients who were male, elderly, low-income, and had a higher baseline diabetes severity were significantly more likely to either continue with their irregular care-seeking behavior or fail to maintain their regular care seeking behavior over time. Those who were younger, had a higher socioeconomic status, and lived in an urban area were significantly more likely to persistently seek care from specialized care settings.

Conclusions: This study is the first population-based assessment of long-term care-seeking behaviors of type 2 diabetes patients under a single-payer system with a comprehensive benefit coverage. The most alarming finding was that, despite the existence of the comprehensive universal health insurance coverage in Taiwan, almost 50% of patients did not seek or maintain regular visits to providers over time as recommended. Understanding variations in the long-term trajectories of care adherence and sources of care may help to identify gaps in diabetes care management.
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http://dx.doi.org/10.1186/s12913-019-4399-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6699076PMC
August 2019

Development and Validation of a New Short-Form Health Literacy Instrument (HLS-SF12) for the General Public in Six Asian Countries.

Health Lit Res Pract 2019 Apr 10;3(2):e91-e102. Epub 2019 Apr 10.

Background: No comprehensive short-form health literacy (HL) survey tool has been available for general use across Asia.

Objective: This study aimed to develop and validate a short-form HL instrument derived from the 47-item European Health Literacy Questionnaire (HLS-EU-Q47).

Methods: A population survey ( = 10,024) was conducted from 2013 to 2015 using the HLS-EU-Q47 in 1,029 participants from Indonesia, 1,845 from Kazakhstan, 462 from Malaysia, 1,600 from Myanmar, 3,015 from Taiwan, and 2,073 from Vietnam. Validation of the short form was evaluated by principle component analysis, internal consistency, Pearson correlation, and regression analysis.

Key Results: Based on responses from six countries, a 12-item short-form HL questionnaire (HLS-SF12) was developed, retaining the conceptual framework of the HLS-EU-Q47 and accounting for the high variance of the full-form (i.e., 90% in Indonesia, 91% in Myanmar, 93% in Malaysia, 94% in Taiwan, and 95% in both Kazakhstan and Vietnam). The HLS-SF12 was demonstrated to have adequate psychometric properties, including high reliability (Cronbach's alpha = .85), good criterion-related validity, a moderate and high level of item-scale convergent validity, no floor or ceiling effect, and good model-data-fit throughout the populations in these countries.

Conclusions: The HLS-SF12 was shown to be a valid and reliable tool for HL surveys in the general public in six Asian countries. .

Plain Language Summary: A health literacy survey was conducted from 2013 to 2015 in six Asian countries using the European Health Literacy Questionnaire (HLS-EU-Q47). The collected data were used to develop and validate a comprehensive short-form questionnaire. A health literacy questionnaire with 12 items (HLS-SF12) that retains the original conceptual framework of the HLS-EU-Q47 was demonstrated to be reliable and valid.
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http://dx.doi.org/10.3928/24748307-20190225-01DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6607763PMC
April 2019

Developing a New Marker of Dynamic Hyperinflation in Patients with Obstructive Airway Disease - an observational study.

Sci Rep 2019 05 17;9(1):7514. Epub 2019 May 17.

Institute of Public Health, National Yang Ming University, Taipei, ROC, Taiwan.

Tidal volume at peak exercise and vital capacity ratio (V/VC) and V/inspiratory capacity (IC) were used to differentiate lung expansion in subjects with normal health and chronic obstructive pulmonary disease (COPD) from that in subjects with restrictive ventilation. However, VC and IC variably change due to pseudorestriction of lung volumes. Thus, these variables are currently not recommended. In contrast, total lung capacity (TLC) does little change during exercise. The aims of the study investigated whether V/TLC is more significantly correlated with static air trapping and lung hyperinflation in patients with COPD than V/IC, V/FVC, and V/SVC (study 1), and developed a marker to replace dynamic IC maneuvers by evaluation of the relationship between end-expiratory lung volume (EELV) and V/TLC and identification of a cutoff value for V/TLC (study 2). One hundred adults with COPD (study 1) and 23 with COPD and 19 controls (study 2) were analyzed. Spirometry, lung volume, diffusing capacity, incremental cardiopulmonary exercise tests with dynamic IC maneuvers were compared between groups. An ROC curve was generated to identify a cut off value for V/TLC. In study 1, V/TLC was more significantly associated with airflow obstruction, static air trapping and hyperinflation. In study 2, V/TLC was highly correlated with EELV in the patients (r = -0.83), and V/TLC ≥ 0.27 predicted that 18% of the patients with static air trapping and hyperinflation can expand their V equivalent to the controls. In conclusions, V/TLC was superior to other V/capacities. V/TLC may be a marker of dynamic hyperinflation in subjects with COPD, thereby avoiding the need for dynamic IC maneuvers. V/TLC < 0.27 identified approximately 82% of subjects with COPD who could not adequately expand their tidal volume. As most of our participants were male, further studies are required to elucidate whether the results of this study can be applied to female patients with COPD.
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http://dx.doi.org/10.1038/s41598-019-43893-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6525207PMC
May 2019

Plasma MCP-1 and Cognitive Decline in Patients with Alzheimer's Disease and Mild Cognitive Impairment: A Two-year Follow-up Study.

Sci Rep 2018 01 19;8(1):1280. Epub 2018 Jan 19.

Faculty of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan.

Monocyte chemoattractant protein-1 (MCP-1, also known as chemokine CCL2) is a vital chemokine that mediates inflammation in Alzheimer's disease (AD). We analyzed the associations between the baseline plasma MCP-1 level, longitudinal cognitive changes, and genetic effects of CCL2 rs1024611 and its receptor, CC-chemokine receptor 2 (CCR2) rs1799864, in AD. In total, 310 AD patients and 66 mild cognitive impairment (MCI) patients were followed for 2 years, and 120 controls were recruited at baseline for comparison. After adjusting for covariates using one-way analysis of covariance, AD patients had higher plasma MCP-1 levels compared with MCI patients and controls, and severe AD patients had the highest levels. After adjusting for covariates using generalized estimating equation analysis, the results showed that the baseline MCP-1 level was significantly correlated with changes in the two-year Mini-Mental Status Examination (p = 0.046). The A allele of CCR2 rs1799864 was associated with a higher MCP-1 level in AD and MCI patients. In conclusion, plasma MCP-1 might reflect the risk and disease course of AD. A higher plasma MCP-1 level is associated with greater severity and faster cognitive decline. Additionally, the CCR2 polymorphism may play a role in the regulation of MCP-1/CCR2 signaling in AD.
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http://dx.doi.org/10.1038/s41598-018-19807-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5775300PMC
January 2018

30 years follow-up and increased risks of breast cancer and leukaemia after long-term low-dose-rate radiation exposure.

Br J Cancer 2017 Dec 3;117(12):1883-1887. Epub 2017 Oct 3.

Taipei Hospital, Ministry of Health and Welfare, New Taipei City 242, Taiwan.

Background: The current study followed-up site-specific cancer risks in an unique cohort with 30 years' follow-up after long-term low-dose-rate radiation exposure in Taiwan.

Methods: Six thousand two hundred and forty two Taiwanese people received extra exposure in residential and school buildings constructed with Co-60-contaminated steel from 1982 until informed and relocated in early 1990s. The additional doses received have been estimated. During 1983-2012, 300 cancer cases were identified through the national cancer registry in Taiwan, 247 cases with minimum latent periods from initial exposure. The hazard ratios (HR) of site-specific cancers were estimated with additional cumulative exposure estimated individually.

Results: Dose-dependent risks were statistically significantly increased for leukaemia excluding chronic lymphocytic leukaemia (HR 1.18; 90% CI 1.04-1.28), breast cancers (HR 1.11; 90% CI 1.05-1.20), and all cancers (HR 1.05; 90% CI 1.0-1.08, P=0.04). Women with an initial age of exposure lower than 20 were shown with dose response increase in breast cancers risks (HR 1.38; 90% CI 1.14-1.60; P=0.0008).

Conclusions: Radiation exposure before age 20 was associated with a significantly increased risk of breast cancer at much lower radiation exposure than observed previously.
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http://dx.doi.org/10.1038/bjc.2017.350DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5729469PMC
December 2017

Patterns of Oxygen Pulse Curve in Response to Incremental Exercise in Patients with Chronic Obstructive Pulmonary Disease - An Observational Study.

Sci Rep 2017 09 7;7(1):10929. Epub 2017 Sep 7.

Department of Pulmonary and Critical Care Medicine, Chiayi Chang-Gung Memorial Hospital, Chang-Gung Medical Foundation, Chiayi, Taiwan.

In COPD, pulmonary hyperinflation causes decreased stroke volume thereby decreased oxygen pulse (OP). While OP flattening is related to myocardial ischemia in cardiac patients, OP patterns have seldom been explored in COPD. The aims of the study were to investigate OP-curve patterns and associated factors in COPD. Seventy-five patients with stable COPD were enrolled. The demographics, cardiac size, physiological measurements and stress EKG were compared among OP-curve pattern groups. An algorithm to identify OP-curve patterns was developed in 28 patients. In the remaining 45 patients after excluding two with poor effort, this algorithm revealed 20 (44%) flattening, 16 (36%) increasing, and nine (20%) decreasing patterns. The flattening-type group had lower body mass, cardiac size, and diffusing capacity, and larger lung volumes (p = 0.05-<0.0001) compared to the increasing-type group. During exercise, the flattening-type group had a lower operable OP and more hyperventilation and dyspnea (p = 0.02-<0.01). None had ST-T changes. Most differences were related to body mass and mildly to inspiratory fraction. The decreasing-type group performed higher effort than the increasing-type group (p < 0.05). In conclusion, OP flattening was common and was associated with reduced body mass and pulmonary hyperinflation rather than with myocardial ischemia. The decreasing-type may be caused by motivation to exercise.
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http://dx.doi.org/10.1038/s41598-017-11189-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5589739PMC
September 2017

Health-related behaviors moderate the association between age and self-reported health literacy among Taiwanese women.

Women Health 2018 07 6;58(6):632-646. Epub 2017 Jul 6.

a College of Public Health and Nutrition , Taipei Medical University , Taipei , Taiwan.

The role of health-related behaviors in the association between age and health literacy has not been well-elucidated. The present cross-sectional study evaluated the interactions between age and health-related behaviors in 942 women in Taiwan between February and October 2013. Women aged 18-78 years were randomly sampled and recruited from the national administrative system. Self-reported health literacy was measured by the European Health Literacy Survey Questionnaire (HLS-EU-Q47) in Mandarin, asking about sociodemographics and essential health-related behaviors (watching health-related television, community involvement). The interviews were conducted confidentially by well-trained interviewers after having participants' consent. In multiple linear regression models adjusted for education attainment, self-perceived social status, ability to pay for medication, and health-related behaviors, health literacy was significantly negatively related to age (unstandardized regression coefficient, B = -0.04; 95% confidence interval [CI] = (-0.07; 0.00); p = .03). The lower health literacy among older women was significantly modified by watching health-related television programs (from "rarely/not-at-all", B = -0.08 (-0.12, -0.04), p < .001 to "often"; B = 0.10 (0.07, 0.12); p < .001) and community involvement (from "rarely/not-at-all", B = -0.06 (-0.10, -0.03); p = .001 to "often", B = 0.06 (0.03, 0.08); p < .001). Specific health behaviors were protective of older women's health literacy and likely their health.
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http://dx.doi.org/10.1080/03630242.2017.1333074DOI Listing
July 2018

AlN Surface Passivation of GaN-Based High Electron Mobility Transistors by Plasma-Enhanced Atomic Layer Deposition.

Nanoscale Res Lett 2017 Dec 27;12(1):315. Epub 2017 Apr 27.

National Nano Device Laboratories, No. 26, Prosperity Road 1, Hsinchu, 30078, Taiwan.

We report a low current collapse GaN-based high electron mobility transistor (HEMT) with an excellent thermal stability at 150 °C. The AlN was grown by N-based plasma enhanced atomic layer deposition (PEALD) and shown a refractive index of 1.94 at 633 nm of wavelength. Prior to deposit AlN on III-nitrides, the H/NH plasma pre-treatment led to remove the native gallium oxide. The X-ray photoelectron spectroscopy (XPS) spectroscopy confirmed that the native oxide can be effectively decomposed by hydrogen plasma. Following the in situ ALD-AlN passivation, the surface traps can be eliminated and corresponding to a 22.1% of current collapse with quiescent drain bias (V ) at 40 V. Furthermore, the high temperature measurement exhibited a shift-free threshold voltage (V ), corresponding to a 40.2% of current collapse at 150 °C. The thermal stable HEMT enabled a breakdown voltage (BV) to 687 V at high temperature, promising a good thermal reliability under high power operation.
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http://dx.doi.org/10.1186/s11671-017-2082-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5407397PMC
December 2017

Clinical assessment tests in evaluating patients with chronic obstructive pulmonary disease: A cross-sectional study.

Medicine (Baltimore) 2016 Nov;95(47):e5471

Division of Pulmonary Medicine and Departments of Internal Medicine and Critical Care Medicine School of Medicine, Chung Shan Medical University, Taichung Institute and Department of Public Health, National Yang Ming University, Taipei Department of Nursing, Chung Shan Medical University Hospital, Taichung, Taiwan, ROC.

Exertional dyspnea scales (EDS) and health-related quality-of-life questionnaires (HRQoLQs) are used to assess chronic obstructive pulmonary disease (COPD). The GOLD guidelines categorize patients according to either 1 of these 2 domains, the lung function and the frequency of acute exacerbations in the preceding year, however with inconsistent results. Combining EDS and HRQoLQs may yield better results; however, the best combination is unclear. Whether the EDS quantifies the exercise capacity or the dyspnea perception is also unclear. The study was designed to correlate the EDS with exercise capacity and dyspnea perception and to evaluate the best combination of the EDS and HRQoLQ.Three EDS were compared by exercise capacity and Borg scores at rest and during exercise in 57 patients with COPD. Three HRQoLQs were compared by 4 domains of clinical assessments, and 2 types of exercise. The strength of correlation |r| was categorized by quartiles from <0.3 to ≥0.6.The EDS was better correlated with exercise capacities (|r| = 0.29-0.65, P < 0.05-<0.0001) than with the resting and exertional Borg scores (|r| = 0.08-0.55, P = NS- <0.0001). The EDS were moderately to strongly interrelated, but this correlation was weaker when including Oxygen-cost Diagram (OCD) (with the modified Medical Research Council, mMRC r = -0.56, with the baseline dyspnea index, BDI r = 0.49 vs. mMRC with BDI r = -0.73); however, the OCD had the strongest correlation with walking distance (r = 0.65, vs mMRC r = -0.59, BDI r = 0.5) and peak oxygen uptake (r = 0.39 vs mMRC r = -0.29, BDI r = 0.36). Among the HRQoLQs, the COPD assessment test (CAT) was most strongly correlated with the St. George Respiratory Questionnaire (SGRQ) (r = 0.77) and similar to the SGRQ regarding significant correlations with the other instruments (|r| = 0.29-0.67 vs. 0.36-0.77) but poorly with walking distance (r = -0.02). The OCD was mildly correlated with the CAT (r = -0.4).The EDS was more related to the exercise capacity than to the dyspnea perception and the CAT was most closely related to the other instruments but poorly with walking distance. The OCD can be used to compensate for this weak correlation. The study suggests using the CAT and the OCD simultaneously when undertaking clinical evaluation of patients with COPD.
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http://dx.doi.org/10.1097/MD.0000000000005471DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5134888PMC
November 2016

Effort-reward imbalance and self-rated health among Gambian healthcare professionals.

BMC Health Serv Res 2016 Apr 11;16:125. Epub 2016 Apr 11.

Institute of Environmental and Occupational Health Sciences, National Yang-Ming University, No.155, Sec.2, Li-Nong Street, Taipei, 112, Taiwan, ROC.

Background: The effort-reward imbalance (ERI) model of work stress has been widely applied in investigating association between psychosocial factors at work and health. This study examined associations between perceived psychosocial work stress as measured by the ERI model and self-rated health (SRH) among nurses and environmental health officers (EHOs) working in secondary public healthcare facilities in the Gambia.

Method: A cross-sectional study on a random sample of 287 health care professionals (201 nurses and 86 EHOs). A 22-item ERI questionnaire was used to collect data on the psychosocial factors defined by the ERI model. SRH was assessed using a single item measure.

Results: The distribution of subjective health was not statistically different between nurses and EHOs. However, our study uncovered significant associations between perceived psychosocial work stress and subjective health. Specifically, we found that a perceived high effort-reward imbalance (ER-ratio > 1) is a significant risk factor for poor SRH, in both occupational groups. However, over-commitment was not significantly associated with poor SRH in the two groups. When efforts and rewards were considered as separate variables in the analysis, rewards were inversely associated with poor SRH in both groups.

Conclusion: Because of the high perceived Effort-Reward Imbalance among healthcare professionals at secondary public healthcare facilities, it is necessary to modify working conditions through improvement of psychosocial work environment, such as reasonable allocation of resources to increase pay, incentives or other forms of rewards from government. Interventions that could mitigate and prevent stress at work are worth considering in future healthcare policies.
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http://dx.doi.org/10.1186/s12913-016-1347-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4828755PMC
April 2016

Revisiting Unplanned Endotracheal Extubation and Disease Severity in Intensive Care Units.

PLoS One 2015 20;10(10):e0139864. Epub 2015 Oct 20.

Institute and Department of Public Health, National Yang Ming University, Taipei, Taiwan.

Most reports regarding unplanned extubation (UE) are case-control studies with matching age and disease severity. To avoid diminishing differences in matched factors, this study with only matching duration of mechanical ventilation aimed to re-examine the risk factors and the factors governing outcomes of UE in intensive care units (ICUs). This case-control study was conducted on 1,775 subjects intubated for mechanical ventilation. Thirty-seven (2.1%) subjects with UE were identified, and 156 non-UE subjects were randomly selected as the control group. Demographic data, acute Physiological and Chronic Health Evaluation II (APACHE II) scores, and outcomes of UE were compared between the two groups. Logistic regression analysis was used to identify the risk factors of UE. Milder disease, younger age, and higher Glasgow Coma Scale (GCS) scores with more frequently being physically restrained (all p<0.05) were related to UE. Logistic regression revealed that APACHE II score (odds ratio (OR) 0.91, p<0.01), respiratory infection (OR 0.24, p<0.01), physical restraint (OR 5.36, p<0.001), and certain specific diseases (OR 3.79-5.62, p<0.05) were related to UE. The UE patients had a lower ICU mortality rate (p<0.01) and a trend of lower in-hospital mortality rate (p = 0.08). Cox regression analysis revealed that in-hospital mortality was associated with APACHE II score, age, shock, and oxygen used, all of which were co-linear, but not UE. The results showed that milder disease with higher GCS scores thereby requiring a higher use of physical restraints were related to UE. Disease severity but not UE was associated with in-hospital mortality.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0139864PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4617893PMC
June 2016

Health Literacy in Taiwan: A Population-Based Study.

Asia Pac J Public Health 2015 Nov 29;27(8):871-80. Epub 2015 Sep 29.

Taipei Medical University, Taipei, Taiwan Taipei Hospital, Ministry of Health and Welfare, Taiwan

Data on health literacy (HL) in the population is limited for Asian countries. This study aimed to test the validity of the Mandarin version of the European Health Literacy Survey Questionnaire (HLS-EU-Q) for use in the general public in Taiwan. Multistage stratification random sampling resulted in a sample of 2989 people aged 15 years and above. The HLS-EU-Q was validated by confirmatory factor analysis with excellent model data fit indices. The general HL of the Taiwanese population was 34.4 ± 6.6 on a scale of 50. Multivariate regression analysis showed that higher general HL is significantly associated with the higher ability to pay for medication, higher self-perceived social status, higher frequency of watching health-related TV, and community involvement but associated with younger age. HL is also associated with health status, health behaviors, and health care accessibility and use. The HLS-EU-Q was found to be a useful tool to assess HL and its associated factors in the general population.
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http://dx.doi.org/10.1177/1010539515607962DOI Listing
November 2015

Adjunctive Treatment with Rhodiola Crenulata in Patients with Chronic Obstructive Pulmonary Disease--A Randomized Placebo Controlled Double Blind Clinical Trial.

PLoS One 2015 22;10(6):e0128142. Epub 2015 Jun 22.

Institute and Department of Public Health, National Yang Ming University, Taipei, Taiwan.

Unlabelled: Chronic obstructive pulmonary disease (COPD) is a low grade systemic inflammatory disease characterized by dyspnea and exercise intolerance even under standard therapy. Rhodiola crenulata (RC) has been shown to exert anti-inflammatory effects and to enhance exercise endurance, thereby having the potential to treat COPD. In this 12-week, randomized, double-blind, placebo-controlled clinical trial, 57 patients with stable moderate-to-severe COPD aged 70±8.8 years were given RC (250 mg twice/day) (n=38) or a placebo (250 mg twice/day) (n=19) in addition to their standard regimen. There were no significant differences in anthropometrics, quality of life, lung function, six-minute walk and incremental exercise tests between the two groups at enrollment. Over the 12 weeks, RC was well tolerated, significantly reduced triceps skin thickness (Δ=-1 mm, p=.04), change of FEV1 (4.5%, p=.03), and improved workload (Δ=10%, p=.01); although there were no significant differences in these factors between the two groups. However, there were significant between-group differences in tidal volume and ventilation-CO2-output ratio at peak exercise (both p=.05), which were significantly related to peak work rate (both p<.0001). RC tended to protect against acute exacerbation of COPD (p=.1) but not other measurements. RC did not improve the six-minute walk test distance but significantly improved tidal breathing and ventilation efficiency, most likely through improvements in work rate. Further studies with a larger patient population are needed in order to confirm these findings.

Trial Registration: ClinicalTrials.gov number NCT02242461.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0128142PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4476627PMC
May 2016

The serologic decoy receptor 3 (DcR3) levels are associated with slower disease progression in HIV-1/AIDS patients.

J Formos Med Assoc 2015 Jun 13;114(6):498-503. Epub 2013 Mar 13.

AIDS Prevention and Research Centre, National Yang-Ming University, Taipei 11221, Taiwan; Department of Microbiology, School of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan. Electronic address:

Background/purpose: The decoy receptor 3 (DcR3) is a member of the tumor necrosis factor receptor (TNFR) super-family. It counteracts the biological effects of Fas ligands and inhibits apoptosis. The goals of this study were to understand the associations between serologic DcR3 (sDcR3) levels and different human immunodeficiency virus type 1 (HIV-1) subtypes, as well as the AIDS disease progression.

Methods: Serum samples from 61 HIV/AIDS patients, who had been followed up every 6 months for 3 years, were collected. sDcR3 levels were quantified using an enzyme immunoassay (EIA).

Results: The sDcR3 levels in patients with HIV-1 subtype B were significantly higher than those in patients infected with subtype CRF01_AE (p < 0.001). In addition, multivariable linear mixed model analysis demonstrated that HIV-1 subtype B and slow disease progression were associated with higher levels of sDcR3, adjusting for potential predictors (p = 0.0008 and 0.0455, respectively).

Conclusion: HIV-1-infected cells may gain a survival advantage by activating DcR3, which prevents infected cell detection by the host immune system. These data indicate that the sDcR3 level is a biomarker for AIDS disease progression.
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http://dx.doi.org/10.1016/j.jfma.2013.01.007DOI Listing
June 2015

Associations of Metabolic Syndrome and its Components With Mortality in the Elderly: A Cohort Study of 73,547 Taiwanese Adults.

Medicine (Baltimore) 2015 Jun;94(23):e956

From the Section of Infectious Diseases, Taipei City Hospital, Taipei City Government (YY); School of Medicine, National Yang-Ming University (YY, YL, VYS, SP, WS); Department of Education and Research, Taipei City Hospital (HH); Institute of Public Health, National Yang-Ming University, Taipei (HH, IL); Division of Endocrinology and Metabolism, Department of Internal Medicine, Puli Branch of Taichung Veterans General Hospital, Nantou (YL); Department of Chest Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC (VYS, SP, WT, WS).

Available evidence shows that metabolic syndrome (Mets) has clear adverse effects for middle-aged and pre-elderly adults; however, the effect of Mets on mortality among elderly adults remains unclear. In addition, the comparative utility of Mets and its component for predicting mortality among the elderly has not been clearly established. Using data from a large Taiwanese cohort, we evaluated the effect of Mets and its components on subsequent all-cause and cause-specific mortality overtime among the elderly. A total of 73,547 elders (age ≥65 years) participated in the Taipei Elderly Health Examination Program from 2007 to 2010. Mets was diagnosed using the adult treatment panel III criteria, and mortality was ascertained by using national death records. Time-dependent analysis was used to evaluate associations of Mets and its components with all-cause mortality, cardiovascular disease (CVD) mortality, and expanded CVD mortality. This retrospective cohort study found that 42.6% of elders had Mets. During 194,057 person-years of follow-up, 2944 deaths were observed. After adjusting for sociodemographic characteristics and comorbidities, Mets was associated with increased risk of expanded CVD mortality (hazard ratio [HR], 1.27; 95% CI, 1.10-1.46) but not all-cause or CVD mortality. Among Mets components, decreased high-density lipoprotein cholesterol (HDL-C, HR 1.25, 95% CI 1.13-1.37) and hyperglycemia (HR 1.21, 95% CI 1.12-1.31) were associated with a significant increase in all-cause mortality. Hypertension and low HDL-C were predictors of CVD mortality and expanded CVD mortality, and, as compared with Mets, were associated with a higher risk of expanded CVD mortality. The present findings indicate that, in elderly adults, individual components of Mets are better predictors of all-cause and cause-specific mortality than is Mets as a whole. Our results suggest that future efforts should focus on preventing and managing individual risk factors (particularly hypertension, low HDL-C, and hyperglycemia) rather than on "diagnosing" Mets in elders.
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http://dx.doi.org/10.1097/MD.0000000000000956DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4616481PMC
June 2015

The incidence of Japanese encephalitis in Taiwan--a population-based study.

PLoS Negl Trop Dis 2014 Jul 24;8(7):e3030. Epub 2014 Jul 24.

Centers for Disease Control, Ministry of Health and Welfare, Taipei, Taiwan, Republic of China; Division of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, Republic of China.

Background: A mass Japanese encephalitis (JE) vaccination program targeting children was launched in Taiwan in 1968, and the number of pediatric JE cases substantially decreased thereafter. The aim of this study was to elucidate the long-term trend of JE incidence, and to investigate the age-specific seroprevalence of JE-neutralizing antibodies.

Methodology/principal Findings: A total of 2,948 laboratory-confirmed JE cases that occurred between 1966 and 2012 were analyzed using a mandatory notification system managed by the Centers for Disease Control, Taiwan. A total of 6,594 randomly-sampled serum specimens obtained in a nationwide population-based survey in 2002 were analyzed to estimate the seroprevalence of JE-neutralizing antibodies in the general population. The average annual JE incidence rate of the group aged 30 years and older was 0.167 cases per 100,000 people between 2001 and 2012, which was higher than the 0.052 cases per 100,000 people among those aged under 30 years. These seroepidemiological findings indicate that the cohort born between 1963 and 1975, who generally received two or three doses of the vaccine and were administered the last booster dose more than 20 years ago, exhibited the lowest positive rate of JE-neutralizing antibodies (54%). The highest and second highest antibody rates were observed, respectively, in the oldest unvaccinated cohort (86%) and in the youngest cohort born between 1981 and 1986, who received four doses 10-15 years ago (74%).

Conclusion/significance: Over the past decade, the main age group of the confirmed JE cases in Taiwan shifted from young children to adults over 30 years of age. People who were born between 1963 and 1975 exhibited the lowest seroprevalence of JE-neutralizing antibodies. Thus, the key issue for JE control in Taiwan is to reduce adult JE cases through a cost-effective analysis of various immunization strategies.
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http://dx.doi.org/10.1371/journal.pntd.0003030DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4109885PMC
July 2014

Risk factors of depression after prolonged low-dose rate environmental radiation exposure.

Int J Radiat Biol 2014 Oct 11;90(10):859-66. Epub 2014 Aug 11.

Institute of Environmental and Occupational Health Sciences, School of Medicine, National Yang-Ming University , Taipei.

Purpose: More than 10,000 Taiwanese people were exposed to excessive protracted low-dose rate radiation from contaminated reinforcement bars, which were installed in buildings before 1992. This study was conducted to assess the prevalence of depression amongst the exposed and identify related determinants now that more than two decades have passed since this population was informed of their exposure to radiation.

Materials And Methods: We used the Beck depression inventory (BDI)-1A questionnaire to survey 2143 eligible people during their annual physical examinations between March 2009 and December 2009. In total, 1621 people participated in the survey. We employed multivariate logistic regression models with generalized estimating equations method to identify the determinants of depression.

Results: The prevalence of depression (BDI-IA score ≥ 12) was 18.7%. Those who exhibited higher cumulative exposure [adjusted odds ratio (OR): 1.46, 95% confidence interval (CI): 1.02-2.07] and a previous history of depression (adjusted OR: 2.49, 95% CI: 1.36-4.58) were significantly associated with the risk of depression, whereas education level was inversely related to depression (adjusted OR: 0.71, 95% CI: 0.50-0.99).

Conclusion: Long-term, low-dose rate radiation exposure early in life might cause subsequent psychological stress and an increased risk of depression decades later.
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http://dx.doi.org/10.3109/09553002.2014.916830DOI Listing
October 2014

Noncancer hospice care in taiwan: a nationwide dataset analysis from 2005 to 2010.

J Palliat Med 2014 Apr 18;17(4):407-14. Epub 2014 Feb 18.

1 Division of Family Medicine, National Yang-Ming University Hospital , Yilan, Taiwan .

Unlabelled: Abstract Background: The National Health Insurance program (NHI) in Taiwan has provided hospice services since 2000, and it was expanded to noncancer illnesses in September 2009. The issues of noncancer hospice care and the impact of the expanded hospice policy remain unclear.

Methods: Data were collected retrospectively from claims data of hospice admissions using the NHI Research Database of 2005-2010.

Results: A total of 359 noncancer subjects and 412 hospice admissions were enrolled; 1795 age- and gender-matched cancer patients and 2578 hospice admissions were selected as a comparison group. Noncancer hospice care increased markedly after the third quartile of 2009. The most common noncancer diagnosis was "other diseases of the lung" (23.9%). The noncancer subjects had a significantly lower frequency of admissions, lower Charlson Comorbidity Index (CCI) scores, shorter hospice stay, and higher mortality rate than the cancer subjects. Family physicians provided the majority of hospice services in both groups. Acute low respiratory conditions (ALRC) were the most common acute comorbidity in deceased subjects. The noncancer decedents had more ALRC, sepsis/bacteremia, nontraumatic shock, acute myocardial infarctions, and esophageal varicose bleeding than the comparison group. The mean inpatient charges differed insignificantly between both groups. The noncancer subjects correlated negatively with CCI (odds ratio [OR] 0.59 in all hospice admissions; 0.63 in decedents), but positively with a hospice stay ≤3 days, mortality, sepsis/bacteremia, ALRC, nontraumatic shock, and acute myocardial infarctions compared with the cancer subjects (OR 1.42, 1.98, 2.24, 2.36, 2.17, and 11.68, respectively, adjusted by CCI).

Conclusions: The expanded palliative care policy has impacted positively on noncancer hospice care in Taiwan. The terminal noncancer patients had higher risks for short hospice stay, sepsis, nontraumatic shock, and respiratory and heart problems than the cancer subjects. Early referral to hospices is required for terminal patients in Taiwan. The CCI had a limited role for cost/severity evaluations of hospice care.
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http://dx.doi.org/10.1089/jpm.2013.0528DOI Listing
April 2014

Clinical characteristics and lung function in chronic obstructive pulmonary disease complicated with impaired peripheral oxygenation.

Intern Emerg Med 2014 Sep 6;9(6):633-40. Epub 2013 Sep 6.

Division of Pulmonary Medicine and Department of Critical Care Medicine, Chung Shan Medical University Hospital, #110, Section 1, Chien-Kuo North Road, South District, Taichung, 40201, ROC Taiwan,

During exercise testing, patients with chronic obstructive pulmonary disease (COPD) often present with ventilatory limitations and various combinations of impaired peripheral oxygenation (IPO) to the exercising muscles. The entities of IPO include anemia, circulation impairment and deconditioning. COPD-IPO is not widely accepted as being a subgroup of COPD. Therefore, the aim of this study was to evaluate the clinical features of COPD-IPO patients. Forty-seven COPD patients underwent cardiopulmonary exercise testing. COPD-IPO was identified when all IPO variables had abnormal values. The patients who did not meet the COPD-IPO criteria were defined as the NIPO group. The variables with abnormal values included peak oxygen uptake (VO₂) <85% predicated, anaerobic threshold <40% VO₂max pred, VO₂-work rate slope <8.6 ml/watt, oxygen pulse <80%pred, and ventilatory equivalents for O₂ and CO₂ at nadir (>31 and >34, respectively). Anthropometrics, biochemistry, and lung function were compared between the groups. Forty-six COPD patients were enrolled after excluding one patient who had technical difficulties in performing the exercise tests. Despite FEV1 and FVC being similarly reduced (p = NS) between the groups, the COPD-IPO (n = 13, 28%) patients had lower body mass index and were taller, and had impaired diffusing capacity and larger total lung capacity and air-trapping (all p < 0.05). We concluded that COPD patients with all six variables having abnormal values are a unique subgroup and that identification of these patients is worthwhile for further investigations and management such as exercise training and nutritional supplements.
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http://dx.doi.org/10.1007/s11739-013-0989-8DOI Listing
September 2014

Kinetics of changes in oxyhemoglobin saturation during walking and cycling tests in COPD.

Respir Care 2014 Mar 13;59(3):353-62. Epub 2013 Aug 13.

Division of Pulmonary Medicine, Department of Critical Care Medicine, Chung Shan Medical University Hosptial, and School of Medicine, Chung Shan Medical University, Taichung, Taiwan.

Background: The patterns and kinetics of changes in SpO2 in the 6-min walk test (6MWT) and cycling test have not been addressed in patients with COPD.

Methods: We studied 60 COPD subjects, with a mean ± SD FEV1 of 54 ± 18% of predicted. We compared the changes in SpO2 (ΔSpO2) within and between the 2 tests, and the differences between the desaturators and non-desaturators.

Results: In the 6MWT there were 4 patterns of SpO2. Desaturation then resaturation was the most common (46%). ΔSpO2 ≥ 3% occurred at approximately 1.2 min, and the nadir was at 3.5 min where resaturation occurred thereafter. The ΔSpO2 between the start and the nadir (start-vs-nadir ΔSpO2) was greater than the start-vs-end ΔSpO2 (P < .001). The desaturators had less inspiratory muscle strength, worse dyspnea, and shorter 6-min walk distance, whereas the resaturators had greater FEV1/FVC and less functional residual capacity (all P < .05). In the cycling test there were 3 patterns of SpO2. Desaturation was the most common (57%). The ΔSpO2 ≥ 3% and nadir SpO2 occurred at 4.6 min and 6.6 min, respectively, of the 6.8-min cycling exercise duration. The desaturators had lower body mass index, lower oxygen-cost diagram score, less post-exercise inspiratory muscle strength, lower diffusing capacity, lower SpO2, lower work during 6MWT, and lower peak exercise performance (all P < .05). In both tests, the start-vs-nadir ΔSpO2 during the 6MWT was greater (P = .02) but the start-vs-end ΔSpO2 was similar (P = .79). The desaturators in both tests had lower oxygen-cost-diagram scores (P < .01) and poorer peak exercise performance.

Conclusions: Measurement of start-vs-nadir ΔSpO2 rather than start-vs-end ΔSpO2 during the 6MWT is recommended, because start-vs-nadir ΔSpO2 is greater, and the nadir SpO2 is earlier. In both the 6MWT and the cycling exercise test, desaturation can be predicted with the oxygen-cost-diagram score, which has more capability to predict peak exercise performance than the 6MWT.
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http://dx.doi.org/10.4187/respcare.02494DOI Listing
March 2014

Impact of tobacco control policies on adolescent smoking: findings from the Global Youth Tobacco Survey in Taiwan.

Addiction 2013 Oct 24;108(10):1829-35. Epub 2013 Jul 24.

Institute of Public Health, National Yang Ming University, Taipei, Taiwan.

Aims: To assess the impact of a set of comprehensive tobacco control policies implemented in Taiwan in 2009, including extensive smoke-free policy, advertisement ban, pictorial warning and price increase, on adolescent smoking prevalence.

Design: Five waves of cross-sectional surveys.

Setting: Taiwan, 2004-11.

Participants: Nationally representative sample of junior high schools aged 13-15 years, in a biennial survey, total sample size 101,100.

Measures: Core questionnaire of the Global Youth Tobacco Survey, including ever smoking, 30-day smoking and number of cigarettes smoked. The magnitude of prevalence change before and after the 2009 policy implementation was quantified by adjusted odds ratios estimated by piecewise logistic regression models.

Findings: The 30-day smoking prevalence demonstrated an upward trend [odds ratio (OR) = 1.06, 95% confidence interval (CI) = 1.02-1.10] between 2004 and 2008. Significant decline in 30-day smoking prevalence after the 2009 law implementation was observed (OR = 0.84, 95% CI = 0.71-0.99). Those living in non-city areas demonstrated a greater magnitude of change. In addition to changes in prevalence, we observed some delay in the age starting smoking, reduction in smokers who smoke fewer than one cigarette per day, and decrease in smokers who did not buy cigarettes. The decline in smoking prevalence was contributed primarily by the reduction in experimenters.

Conclusion: The comprehensive tobacco control programme introduced in Taiwan in 2009 was associated with a reduction in adolescent smoking, particularly among those in earlier stages of smoking and those who resided in non-city areas.
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http://dx.doi.org/10.1111/add.12259DOI Listing
October 2013

Shrinkage methods enhanced the accuracy of parameter estimation using Cox models with small number of events.

J Clin Epidemiol 2013 Jul 6;66(7):743-51. Epub 2013 Apr 6.

Institute of Public Health, School of Medicine, National Yang-Ming University, 155 Section 2, Li-Nong Street, Taipei 11221, Taiwan.

Objective: When the number of events is small during Cox regression analysis, it is unclear what alternative analytical strategies can be used and when this type of alternative approach is needed. This study explores several analytical strategies in this situation.

Study Design And Setting: Simulations and sensitivity analyses were performed on data with numbers of events per predictive variable (EPVs) below 10 using a Cox model with a partial likelihood (PL), Firth's penalized likelihood, or the Bayesian approach.

Results: For scenarios involving binary predictors with an EPV of six or less, the simulations showed that the Firth and Bayesian approaches were more accurate than was PL. The performances of various approaches were similar when the EPV was greater than six in the binary predictor. Furthermore, the performances involving continuous predictors were similar, regardless of the EPV. The bias and precision of the parameter estimates using Bayesian analysis depended on the selection of priors.

Conclusions: When the EPV is six or less, the results for categorical predictors tend to be too conservative. Firth's estimator may be a good alternative in this situation. Appropriate choices of priors when using Bayesian analysis should increase the accuracy of the parameter estimates, although this requires expertise.
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http://dx.doi.org/10.1016/j.jclinepi.2013.02.002DOI Listing
July 2013

Disposable income with tobacco smoking among young adolescents: a multilevel analysis.

J Adolesc Health 2013 Jun 21;52(6):724-30. Epub 2013 Mar 21.

Institute of Public Health, National Yang-Ming University, Taipei, Taiwan.

Purpose: Prior studies examining the connection between disposable income and adolescent smoking often yielded mixed results, partly due to the lack of consideration for contextual variables. In the present study, we sought to broaden understanding of disposable income on adolescent smoking behaviors via both absolute and relative perspectives in the school context.

Methods: We obtained data from the 2010 Global Youth Tobacco Survey (GYTS) in Taiwan. Information concerning sociodemographics, disposable income, smoking history, and contextual smoking exposure (e.g., school) were assessed via self-report. Recent-onset smokers were defined as those who had their first cigarette within two years of the survey. Complex survey and multilevel analyses were carried out to estimate association.

Results: Adolescents with higher monthly disposable income were 2∼5 times more likely to start smoking and become regular smokers. Having the least disposable income in a class appeared linked with increased risk of tobacco initiation by 40% (95% confidence interval [CI]: 2%-91%). Pupils' odds to start smoking were lowered to .70 when the majority of schoolmates had low disposable income (95% CI: .51-.99).

Conclusions: Adolescent risk of smoking initiation may be differentially affected by individual- and contextual-level absolute and relative disposable income. Future research is needed to delineate possible mechanisms underlying unfavorable health behaviors associated with disposable incomes in early adolescence.
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http://dx.doi.org/10.1016/j.jadohealth.2012.12.009DOI Listing
June 2013