Background: Adjusting for large numbers of covariates ascertained from patients’ health
care claims data may improve control of confounding, as these variables may collectively be …

Background The safety of alternative analgesics is unclear. We examined the comparative
safety of nonselective NSAIDs (nsNSAIDs), selective cyclooxygenase 2 inhibitors (coxibs), …

Importance Understanding the effect of serum antibodies to severe acute respiratory syndrome
coronavirus 2 (SARS-CoV-2) on susceptibility to infection is important for identifying at-…

Background Among the large number of cohort studies that employ propensity score matching,
most match patients 1:1. Increasing the matching ratio is thought to improve precision but …

Instrumental variable (IV) methods have been proposed as a potential approach to the
common problem of uncontrolled confounding in comparative studies of medical interventions, …

Recent theoretical studies have shown that conditioning on an instrumental variable (IV), a
variable that is associated with exposure but not associated with outcome except through …

Inferring causation from non‐randomized studies of exposure requires that exposure groups
can be balanced with respect to prognostic factors for the outcome. Although there is broad …

Background Severe nonmalignant pain affects a large proportion of adults. Optimal treatment
is not clear, and opioids are an important option for analgesia. However, there is relatively …

Background— Recent studies have raised concerns about the reduced efficacy of clopidogrel
when used concurrently with proton pump inhibitors (PPIs), but those studies may have …

Aims Randomized controlled trials (RCTs) are the gold standard for assessing the efficacy
of therapeutic interventions because randomization protects from biases inherent in …