Addressing missing outcome data in meta-analysis

Abstract

Unlike clinical trials, in systematic reviews and meta-analyses we cannot adapt pre-emptive methods to account for missing outcome data. There are statistical techniques implemented in commercial software (eg, STATA) that quantify the departure from the missing at random assumption and adjust results appropriately. A sensitivity analysis with increasingly stringent assumptions on how parameters in the unobserved and observed data are related is a sensible way to evaluate robustness of results.