The authors of this manuscript tested the ability of Sentinel’s reusable analytic tools to identify the known association between warfarin and gastrointestinal bleeding (GIB). Statins, expected to have no effect on GIB, were the comparator. The authors further explored the impact of analytic features, including matching ratio and stratifying Cox regression analyses, on matched pairs. This study identified the expected GIB risk with warfarin compared with statins using an analytic tool developed for Sentinel. Findings suggest that comparators with different indications may be useful in surveillance in select circumstances. Finally, in the presence of differential censoring, stratification by matched pair may reduce the potential for bias in Cox regression analyses.