Publications by authors named "Claire A Cox"

6 Publications

  • Page 1 of 1

Predicted values for the forced expiratory flow adjusted for forced vital capacity, a descriptive study.

ERJ Open Res 2020 Oct 14;6(4). Epub 2020 Dec 14.

University of Groningen, University Medical Centre Groningen, Dept of Pulmonary Diseases Groningen, The Netherlands.

Background: The forced expiratory flows (FEFs) towards the end of the expiration may be more sensitive in detecting peripheral airways obstruction compared to the forced expiratory volume in 1 s and forced vital capacity (FVC). However, they are highly variable. A partial solution is to adjust the FEFs for FVC (FEF/FVC). Here we provide reference equations for these adjusted FEFs at 25%, 50%, 75% and 25-75% of FVC, which are currently lacking.

Methods: We included pulmonary healthy, never-smoker adults; 14 472 subjects from Lifelines, a biobank for health research, and 338 subjects from the department's control cohorts (NORM and Fiddle). Reference equations were obtained by linear regression on 80% of the Lifelines dataset and validated on the remaining data. The best model was defined as the one with the highest adjusted R-value. The difference in variability between adjusted and unadjusted FEFs was evaluated using the coefficient of variation.

Results: For all adjusted FEFs, the best model contained age, height and weight. The adjustment improved the coefficient of variation of the FEF from 39% to 36% and from 43% to 40%, respectively, in males and females. The highest percentage of explained variance by the reference equation was obtained for FEF/FVC, 32%-38% for males, and 41%-46% for females, depending on the validation set.

Conclusion: We developed reference equations for FVC-adjusted FEF values. We demonstrated minimally yet significantly improved variability. Future studies in obstructive airway diseases should demonstrate whether it is worthwhile to use these (predicted) adjusted FEF values.
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http://dx.doi.org/10.1183/23120541.00426-2020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7737427PMC
October 2020

Associations of AMP and adenosine induced dyspnea sensation to large and small airways dysfunction in asthma.

BMC Pulm Med 2019 Jan 28;19(1):23. Epub 2019 Jan 28.

Department of Pulmonary Diseases, University of Groningen, University Medical Center Groningen, PO box 30.0001, 9700, RB, Groningen, The Netherlands.

Background: Bronchial provocation is often used to confirm asthma. Dyspnea sensation, however, associates poorly with the evoked drop in FEV. Provocation tests only use the large airways parameter FEV, although dyspnea is associated with both large- and small airways dysfunction. Aim of this study was to explore if adenosine 5'-monophosphate (AMP) and adenosine evoke an equal dyspnea sensation and if dyspnea associates better with large or small airways dysfunction.

Methods: We targeted large airways with AMP and small airways with dry powder adenosine in 59 asthmatic (ex)-smokers with ≥5 packyears, 14 ± 7 days apart. All subjects performed spirometry, impulse oscillometry (IOS), and Borg dyspnea score. In 36 subjects multiple breath nitrogen washout (MBNW) was additionally performed. We analyzed the association of the change (Δ) in Borg score with the change in large and small airways parameters, using univariate and multivariate linear regression analyses. MBNW was analyzed separately.

Results: Provocation with AMP and adenosine evoked similar levels of dyspnea. ΔFEV was not significantly associated with ΔBorg after either AMP or adenosine provocation, in both univariate and multivariate analyses. In multivariate linear regression, a decrease in FEF during adenosine provocation was independently associated with an increase in Borg. In the multivariate analyses for AMP provocation, no significant associations were found between ΔBorg and any large or small airways parameters.

Conclusion: AMP and adenosine induce equally severe dyspnea sensations. Our results suggest that dyspnea induced with dry powder adenosine is related to small airways involvement, while neither large nor small airways dysfunction was associated with AMP-induced dyspnea.

Trail Registration: NCT01741285 at www.clinicaltrials.gov , first registered Dec 4th, 2012.
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http://dx.doi.org/10.1186/s12890-019-0783-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6348600PMC
January 2019

Predictors of clinical response to extrafine and non-extrafine particle inhaled corticosteroids in smokers and ex-smokers with asthma.

Respir Res 2018 Dec 18;19(1):256. Epub 2018 Dec 18.

Department of Pulmonary Diseases, University of Groningen, University Medical Center Groningen, PO Box 30.0001, 9700, RB, Groningen, The Netherlands.

We performed a post-hoc analysis of the OLiVIA-study investigating whether current and ex-smoking asthmatics with small airways dysfunction (SAD) show a better response in airway hyperresponsiveness (AHR) to small particle adenosine after treatment with extrafine compared to non-extrafine particle inhaled corticosteroids (ICS), and to investigate which clinical parameters predict a favorable response to both treatments. We show that smoking and ex-smoking asthmatics with and without SAD have a similar treatment response with either extrafine or non-extrafine particle ICS. We also found that lower blood neutrophils are associated with a smaller ICS-response in smokers and ex-smokers with asthma, independent from the level of blood eosinophils.
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http://dx.doi.org/10.1186/s12931-018-0961-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6299530PMC
December 2018

Extrafine compared to non-extrafine particle inhaled corticosteroids in smokers and ex-smokers with asthma.

Respir Med 2017 Sep 8;130:35-42. Epub 2017 Jul 8.

University of Groningen, University Medical Centre Groningen, Department of Pulmonary Diseases, PO Box 30.0001, 9700 RB Groningen, The Netherlands; University of Groningen, University Medical Centre Groningen, Groningen Research Institute for Asthma and COPD, PO Box 30.0001, 9700 RB Groningen, The Netherlands. Electronic address:

Background: Smoking is as prevalent in asthmatics as in the general population. Asthmatic smokers benefit less from inhaled corticosteroids (ICS) than non-smoking asthmatics, possibly due to more smoking-induced small airways disease. Thus targeting small airways may be important in treating asthmatic (ex-)smokers. We hypothesized that extrafine particle ICS improve small airways function more than non-extrafine particle ICS in asthmatic (ex-)smokers.

Methods: We performed an open-label, randomized, three-way cross-over study comparing extrafine beclomethasone (HFA-QVAR) to non-extrafine beclomethasone (HFA-Clenil) and fluticasone (HFA-Flixotide) in 22 smokers and 21 ex-smokers with asthma (?5 packyears).

Results: Improvement from baseline in PD adenosine after using QVAR, Clenil or Flixotide was 1.04 ± 1.71, 1.09 ± 2.12 and 0.94 ± 1.97 doubling doses, mean ± standard deviation (SD), respectively. The change from baseline in R-R at PD adenosine after using QVAR, Clenil or Flixotide was ?0.02 ± 0.27, 0.02 ± 0.21, and ?0.02 ± 0.31 kPa sL, mean ± SD, respectively. The change in PD adenosine and R-R at PD adenosine were neither statistically significant different between QVAR and Clenil (p = 0.86 and p = 0.82) nor between QVAR and Flixotide (p = 0.50 and p = 0.96).

Conclusion: Similar effectiveness in improving small airways function was found for extrafine and non-extrafine particle ICS treatment for asthmatic smokers and ex-smokers.
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http://dx.doi.org/10.1016/j.rmed.2017.07.005DOI Listing
September 2017
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