The Lack of a Standardized Definition of Chronic Dialysis Treatment in German Statutory Health Insurance Claims Data.

BACKGROUND: Chronic kidney failure (CKF) is often treated with dialysis, which is invasive and costly and carries major medical risks. The existing studies of patients with CKF requiring dialysis that are based on claims data from German statutory health insurance (SHI) carriers employ varying definitions of this entity, with unclear consequences for the resulting statistical estimates. METHODS: We carried out a cohort study on four random samples, each consisting of 62 200 persons aged 70 or above, from among the insurees of the SHI AOK Nordost, with one sample for each of the years 2012, 2014, 2016, and 2018. The prevalence, incidence, mortality, and direct health care costs of CKF requiring dialysis were estimated and compared on the basis of four different definitions from literature and a new definition developed by the authors in reference to billing data. RESULTS: The different definitions led to variation in 12-month prevalences (range: 0.33-0.61%) and 6-month incidences (0.058-0.100%). The percentage of patients with prior acute kidney injury (AKI) ranged from 27.6% to 61.8%. Among incident patients, three-month survival ranged from 70.2% to 88.1%, and six-month survival from 60.5% to 81.3%. In CKF patients without prior AKI, the survival curves differed less across definitions (80.2-91.8% at three months, 70.7-84.4% at six months). The monthly health care costs ranged from €6010 to €9606, with marked variability across definitions in the costs of inpatient and outpatient care. CONCLUSION: The lack of a standardized definition of CKF requiring dialysis in German SHI claims data leads to variability in the estimated case numbers, mortality, and health care costs. These differences are most probably in part due to the variable inclusion of inpatients who received short-term dialysis after AKI.

Multistate methodology improves risk assessment under time-varying drug intake-a new view on pregnancy outcomes following coumarin exposure.

PURPOSE: Observational cohort studies are essential to evaluate the risk of adverse pregnancy outcomes associated with drug intake. Besides left truncation and competing events, it is crucial to account for the time-dynamic pattern of drug exposure. In fact, potentially harmful medications are often discontinued, which might affect the outcome. Ignoring these challenges may lead to biased estimation of drug-related risks highlighting the need for adequate statistical techniques. METHODS: We reanalyze updated data of a recently published study provided by the German Embryotox pharmacovigilance institute. The aim of the study was to quantify the effect of discontinuation of vitamin K antagonist phenprocoumon on the risk of spontaneous abortion. RESULTS: We outline multistate methodology as a powerful method removing bias in probability estimation inherent to commonly used crude proportions. We incorporate time-dependent discontinuation and competing pregnancy outcomes as separate states in a multistate model, which enables the formulation of hazard-based Cox proportional hazard models and the application of so-called landmark techniques. Results show that early discontinuation of phenprocoumon substantially reduces the risk of spontaneous abortion, which is of great importance for both pregnant women and treating physicians. CONCLUSIONS: An adequate handling of discontinuation times is essential when analyzing the risk of spontaneous abortion. The proposed concepts are not restricted to pregnancy outcome studies but have broad usage in other fields of epidemiology. Our nontechnical report may provide guidance for the design and analysis of future studies. Example code is provided.

Exposure to cox-2 inhibitors (coxibs) during the first trimester and pregnancy outcome: a prospective observational cohort study.

PURPOSE: Cox-2-inhibitors (coxibs) are not recommended in pregnancy but early exposure may occur, for instance in unplanned pregnancies. Experience in pregnancy is limited leading to concerns in patients and their health care providers. Therefore, further data on coxibs and their effects on embryogenesis are needed. METHODS: This observational cohort study evaluates pregnancies ascertained in Germany during the study period from January 2000 to January 2016. A cohort of 174 women exposed to coxibs in the first trimester was compared to a randomly selected cohort of 521 women without exposure to coxibs, other nonsteroidal anti-inflammatory drugs or known teratogens. RESULTS: The overall rate of major birth defects was not significantly increased in the study cohort (2.9 vs. 2.7%, OR 1.08, 95% CI 0.34-3.42; OR adjusted 0.96, 95% CI 0.28-3.26). The cumulative incidence of spontaneous abortions was nonsignificantly lower in the exposed cohort (14.3 vs. 20.0%; HR, 0.90, 95% CI 0.51-1.58; HR adjusted, 0.87; 95% CI, 0.49-1.56). Elective terminations of pregnancies (ETOP), mainly for 'social' reasons, were more frequent in the coxib cohort (17.5 vs. 7.0%, HR, 2.31; 95% CI, 1.26-4.24; HR adjusted 2.12, 95% CI 1.13-3.97). CONCLUSIONS: Our study results support the assumption that coxibs are not major teratogens. Considering the still limited evidence basis on coxib exposure during pregnancy, well-established alternatives should be preferred.