Suboptimal Performance of Microscopic Colitis Diagnosis Codes: A Bottleneck for Epidemiologic Insights.

Introduction: Administrative health data could contribute to generalizable microscopic colitis insights, but International Classification of Diseases (ICD) codes for microscopic colitis have not been validated.

Methods: We identified individuals who received care for diarrhea in the Veterans Health Administration and classified them by receipt of microscopic colitis ICD codes. We reviewed random samples of charts to calculate the positive predictive value (PPV) and negative predictive value (NPV).

Incidence of life-threatening events in children with Wolff-Parkinson-White syndrome: Analysis of a large claims database.

Background: Previous estimates of life-threatening event (LTE) risk in Wolff-Parkinson-White (WPW) syndrome are limited by selection bias inherent to tertiary care referral-based cohorts.

Objective: This analysis sought to measure LTE incidence in children with WPW syndrome in a large contemporary representative population.

Methods: A retrospective cohort study was conducted using claims data from the IBM MarketScan Research Databases, evaluating subjects with WPW syndrome (age 1-18 years) from any encounter between January 1, 2013, and December 31, 2018.

First trimester mechanisms of gestational sac placental and foetal teratogenicity: a framework for birth cohort studies.

Background: The function of the gestational sac (GS) and the placenta in the closely related processes of embryogenesis and teratogenicity in the first trimester has been minimally described. The prevailing assumption is that direct teratogenic effects are mediated by the critical extraembryonic organ, the placenta, which either blocks or transfers exposures to the foetus. Placental transfer is a dominant mechanism, but there are other paradigms by which the placenta can mediate teratogenic effects.