BACKGROUND: The validity of conclusions from observational studies depends on decisions regarding design, analysis, data quality, and implementation. Through sensitivity analyses, we explored the impact of such decisions on balance control and risk estimates. METHODS: Using as a template the Mini-Sentinel protocol for the active surveillance of @entity583 ( @entity583 ) in association with use of antidiabetic agents, we defined cohorts of new users of @entity2449 and second-generation sulfonylureas, baseline covariates and acute @entity583 events using three combinations of washout and baseline periods. Using propensity-score matching, we assessed balance control and risk estimates using cumulative data for matching all @entity1 compared with not rematching prior matches in quarterly analyses over the follow-up period. RESULTS: A longer washout period increased the confidence in new-user status, but at the expense of sample size; a longer baseline period improved capture of covariates related to pre-existing chronic conditions. When all @entity1 were matched each quarter, balance was improved and risk estimates were more robust, especially in the later quarters. CONCLUSIONS: Durations of washout and baseline periods influence the likelihood of new-user status and sample size. Matching all @entity1 tends to result in better covariate balance than matching only new @entity1 . Decisions regarding the durations of washout and baseline periods depend on the specific research question and @entity3057 @entity1 data within the database. This paper demonstrates the importance and utility of sensitivity analysis of methods for evaluating the robustness of results in observational studies.

Sensitivity analysis of methods for active surveillance of XXXX using electronic databases.

@entity1 :: ('9606', 'Species') :: ['patients', 'patient'] @entity583 :: ('MESH:D009203', 'Disease') :: ['MI', 'acute myocardial infarction'] @entity3057 :: ('MESH:D017887', 'Disease') :: ['availability of longitudinal'] @entity2449 :: ('MESH:D008687', 'Chemical') :: ['metformin']
@entity583 :: (MESH:D009203,Disease) :: ['acute myocardial infarction']
