Publications by authors named "Lotte Brix Christensen"

5 Publications

  • Page 1 of 1

Birthweight and all-cause mortality after childhood and adolescent leukemia: a cohort of children with leukemia from Denmark, Norway, Sweden, and Washington State.

Acta Oncol 2020 Aug 14;59(8):949-958. Epub 2020 Mar 14.

Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark.

High birthweight may predispose children to acute lymphoid leukemia, whereas low birthweight is associated with childhood morbidity and mortality. Low and high birthweight have been inconsistently associated with mortality in children with leukemia. In a cohort of childhood and adolescent leukemia (0-19 years) patients from registries in Denmark, Norway, Sweden, and Washington State in the United States (1967-2015), five-year all-cause mortality was assessed by birthweight and other measures of fetal growth using the cumulative incidence function and Cox regression with adjustment for sex, diagnosis year, country, the presence of Down's syndrome or other malformations, and type of leukemia. Among 7148 children and adolescents with leukemia (55% male), 4.6% were low (<2500 g) and 19% were high (≥4000 g) birthweight. Compared with average weight, hazard ratios (HRs) of death associated with low birthweight varied by age at leukemia diagnosis: 1.5 (95% confidence interval (CI): 0.7, 3.2) for patients 0-1 year old, 1.6 (95% CI: 1.0, 2.6) for >1-2 years old; 1.0 (95% CI: 0.6, 1.5) for 3-8 years old; 1.0 (95% CI: 0.6, 1.8) for 9-13 years old; and 1.2 (95% CI: 0.7, 2.1) for 14-19 years old, and were similar for size for gestational age and Ponderal index. In analyses restricted to children born full term (37-41 weeks of gestation), results were only slightly attenuated but risk was markedly increased for infants aged ≤1 year (HR for low birthweight = 3.2, 95% CI: 1.2, 8.8). This cohort study does not suggest that low birthweight or SGA is associated with increased five-year all-cause mortality risk among children with any type of childhood leukemia or acute lymphoblastic leukemia, specifically, beyond infancy.
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August 2020

Validity of asthma diagnoses and patterns of anti-asthmatic drug use in a cohort of 2053 Danish children.

Health Sci Rep 2018 Sep 24;1(9):e77. Epub 2018 Jul 24.

Department of Clinical Epidemiology, Institute of Clinical Medicine Aarhus University Hospital Aarhus Denmark.

Background And Aims: When investigating and treating asthma in children, diagnosing must be precise and valid. There is a need for studies researching asthma in children showing how to use registry-based, epidemiological data. We examined the feasibility and validity of using anti-asthmatic drug prescription data to identify children with asthma and assessed medication patterns in children with and without confirmed asthma.

Methods: We used population-based Danish prescription data and hospital discharge registries to identify all children aged 0 to 14 years who had redeemed at least one prescription for an inhaled anti-asthmatic drug. Individual asthma cases were validated by hospital discharge information and by their treating general practitioners according to international asthma guidelines.

Results: In total, 2053 children, out of a population of 20181, had redeemed at least one prescription of any inhaled anti-asthmatic drug. The positive predictive value (PPV) of having two different asthma medications prescribed in 1 year was 80.2% for presence of true asthma, with a sensitivity of 59%. Corresponding estimates of PPV/sensitivity of at least one prescription for an inhaled corticosteroid (ICS) were 79% and 58%, respectively, while the true asthma PPV with at least one LABA prescription increased to 97%. Among children with confirmed asthma, one-third had not used Beta2-agonist therapy as part of their treatment. Conversely, among children without confirmed asthma, 40% were prescribed a minimum of two prescriptions for any kind of inhaled anti-asthmatic drug, and 12% and 9% used an ICS or Leukotriene receptor antagonist, respectively.

Conclusions: Anti-asthmatic drug prescription data could be used to identify children with true asthma, with reasonable accuracy. The observed pattern of anti-asthmatic medication usage among children with and without confirmed asthma suggests that there is room for therapeutic improvement.
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September 2018

One-year rehospitalisation after percutaneous coronary intervention: a retrospective analysis.

EuroIntervention 2018 Oct;14(8):926-934

Department of Cardiology, Odense University Hospital, Odense, Denmark.

Aims: The aim of the study was to evaluate the incidence and causes of rehospitalisation within one year after percutaneous coronary intervention (PCI) in a country where the National Health Service provides universal tax-supported healthcare, guaranteeing residents free hospital access.

Methods And Results: Between January 2010 and September 2014, 17,111 patients were treated with PCI in two University Hospitals in Western Denmark. Patients who were readmitted within one year after PCI were identified. The overall one-year readmission rate was 50.4%. The cause was angina/myocardial infarction (MI) in 4,282 patients (49.7%), and other reasons in 4,334 (50.3%). Predictors of angina/MI-related readmissions were female gender (odds ratio [OR] 1.15, 95% confidence interval [CI]: 1.07-1.25), diabetes (OR 1.14, 95% CI: 1.04-1.26), age (per 10-year increase) (OR 0.86, 95% CI: 0.83-0.88), and indication for index PCI (stable angina pectoris as reference): ST-segment elevation myocardial infarction (OR 1.34, 95% CI: 1.23-1.47) and non-ST-segment elevation myocardial infarction (OR 1.18, 95% CI: 1.08-1.29). Predictors for other readmissions were female gender (OR 1.09, 95% CI: 1.01-1.18), diabetes (OR 1.29, 95% CI: 1.18-1.42), age (OR 1.30, 95% CI: 1.26-1.34) and Charlson comorbidity index ≥3 (OR 3.03, 95% CI: 2.71-3.27).

Conclusions: In an unselected patient cohort treated with PCI, half of the patients were rehospitalised within one year, highlighting the impact of comorbidity in patients with ischaemic heart disease.
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October 2018

Association Between Methylphenidate and Amphetamine Use in Pregnancy and Risk of Congenital Malformations: A Cohort Study From the International Pregnancy Safety Study Consortium.

JAMA Psychiatry 2018 02;75(2):167-175

Division of Pharmacoepidemiology and Pharmacoeconomics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts.

Importance: Given the rapidly increasing use of stimulant medications during pregnancy and among women of reproductive age who may become pregnant inadvertently, there is a need to better understand their safety.

Objective: To examine the risk of congenital malformations associated with intrauterine exposure to stimulants.

Design, Setting, And Participants: Cohort study of the Medicaid-insured population in the United States nested in the 2000-2013 US Medicaid Analytic eXtract, with follow-up of safety signals detected in the Medicaid Analytic eXtract data using the Nordic Health registries (2003-2013) (Denmark, Finland, Iceland, Norway, and Sweden). A total of 1 813 894 publicly insured pregnancies in the United States and 2 560 069 singleton pregnancies in the 5 Nordic countries ending in live births were included. Relative risks were estimated accounting for underlying psychiatric disorders and other potential confounders. Relative risk estimates for the US and Nordic data were pooled using a fixed-effects meta-analytic approach. The study was conducted from July 1, 2015, to March 31, 2017.

Exposures: Methylphenidate and amphetamines dispensed during the first trimester.

Main Outcomes And Measures: Major congenital malformations and subgroup of cardiac malformations.

Results: In the US data, of the 1 813 894 pregnancies evaluated, 35.0 per 1000 infants not exposed to stimulants were diagnosed as having congenital malformations, compared with 45.9 per 1000 infants for methylphenidate and 45.4 for amphetamines. For cardiac malformations, the risks were 12.7 (95% CI, 12.6-12.9), 18.8 (95% CI, 13.8-25.6), and 15.4 (95% CI, 12.5-19.0) per 1000 infants, respectively. The adjusted relative risks for methylphenidate were 1.11 (95% CI, 0.91-1.35) for any malformation and 1.28 (95% CI, 0.94-1.74) for cardiac malformations. No increased risks were observed for amphetamines: 1.05 (95% CI, 0.93-1.19) for any malformations and 0.96 (95% CI, 0.78-1.19) for cardiac malformations. Findings were confirmed in sensitivity analyses accounting for proxies of unmeasured confounders and increasing the specificity of the exposure and outcome definitions. Replication of the analyses for methylphenidate using the Nordic data including 2 560 069 pregnancies yielded a relative risk of 1.28 (95% CI, 0.83-1.97) for cardiac malformations, resulting in a pooled estimate of 1.28 (95% CI, 1.00-1.64).

Conclusions And Relevance: These findings suggest a small increase in the risk of cardiac malformations associated with intrauterine exposure to methylphenidate but not to amphetamines. This information is important when weighing the risks and benefits of alternative treatment strategies for attention-deficit/hyperactivity disorder in women of reproductive age and during early pregnancy.
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February 2018

Positive predictive values of International Classification of Diseases, 10th revision codes for dermatologic events and hypersensitivity leading to hospitalization or emergency room visit among women with postmenopausal osteoporosis in the Danish and Swedish national patient registries.

Clin Epidemiol 2017 24;9:179-184. Epub 2017 Mar 24.

Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus N, Denmark.

Background: Clinical epidemiology research studies, including pharmacoepidemiology and pharmacovigilance studies, use routinely collected health data, such as diagnoses recorded in national health and administrative registries, to assess clinical effectiveness and safety of treatments. We estimated positive predictive values (PPVs) of International Classification of Diseases, 10th revision (ICD-10) codes for primary diagnoses of dermatologic events and hypersensitivity recorded at hospitalization or emergency room visit in the national patient registries of Denmark and Sweden among women with postmenopausal osteoporosis (PMO).

Methods: This validation study included women with PMO identified from the Danish and Swedish national patient registries (2005-2014). Medical charts of the potential cases served as the gold standard for the diagnosis confirmation and were reviewed and adjudicated by physicians.

Results: We obtained and reviewed 189 of 221 sampled medical records (86%). The overall PPV was 92.4% (95% confidence interval [CI], 85.1%-96.3%) for dermatologic events, while the PPVs for bullous events and erythematous dermatologic events were 52.5% (95% CI, 37.5%-67.1%) and 12.5% (95% CI, 2.2%-47.1%), respectively. The PPV was 59.0% (95% CI, 48.3%-69.0%) for hypersensitivity; however, the PPV of hypersensitivity increased to 100.0% (95% CI, 67.6%-100.0%) when restricting to diagnostic codes for anaphylaxis. The overall results did not vary by country.

Conclusion: Among women with PMO, the PPV for any dermatologic event recorded as the primary diagnosis at hospitalization or at an emergency room visit was high and acceptable for epidemiologic research in the Danish and Swedish national patient registries. The PPV was substantially lower for hypersensitivity leading to hospitalization or emergency room visit.
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March 2017