Analysis of treatment switching using observational data

Could a case-crossover design be useful? The most fundamental limitation of a case-crossover study is inherent in the question it is designed to answer, “Was this event triggered by anything unusual that happened just before?” Answering this question is seldom sufficient. If one also wants to test hypotheses concerning chronic exposures, a traditional case control study must be conducted simultaneously or the case-crossover study must be nested in a cohort study maclure2000.pdf (358.3 KB)