Purpose of review: Clinical trials to evaluate the supportive and palliative care treatments have some different missing data concerns than the other clinical trials. This study reviews the literature on missing data as it may apply to these trials.
Recent findings: Prevention of missing data through study design and conduct is a recent area of focus. Missing data can be minimized by simplifying trial participation for patients, their caregivers, and trialists. Run-in periods with active drug or collecting data from observer (proxy) respondents may complicate a trial but may be used to address some specific concerns. Many analyses can accommodate data missing because of nonresponse by multiple imputation, using carefully chosen imputation models. Analysis of trials evaluating end-of-life care should distinguish between missing data and truncation because of death.
Summary: Likely patterns for missing data should be discussed when planning a clinical trial, as modifications to trial design can minimize missing data while still addressing study aims. Many statistical analysis methods are available to accommodate missing data, but robustness of study conclusions to assumptions about mechanisms underlying the missingness should be evaluated by sensitivity analyses.