Checklist for clinical applicability of subgroup analysis

What is known and objective Subgroup analysis plays an important role in clinical decision-making. Correct management of subgroup analysis is necessary to optimize effectiveness, safety and efficiency of treatments. No homogeneous criteria have been developed for interpretation of subgroup analysis. In this study, the researcher develops a checklist to evaluate the reliability and applicability of the results of subset analyses. Methods With a review of previous literature, three main criteria were included in the checklist: statistical association, biological plausibility and consistency among studies. Statistical association considered interaction probability, prespecification of analysis, number of subgroups analysed, sample size and positive/negative result in global analysis. Each item was given an indicative score. Total score was related to a level of applicability for the results in clinical practice. Checklist validation included interinvestigator concordance and assessment about utility. Three drug examples were used to validate the tool. Results and discussion Twenty-six evaluators showed adequate interinvestigator concordance (kappa 0.79, 1 and 0.83 for each drug example regarding applicability). Kappa values increased to 0.94, 1 and 1 after group discussion. Checklist utility score was greater than 4.7/5 in three drug examples. In pre-analysis, inter-researcher agreement on global applicability recommendation of subgroup results to practice was 92.3% (ramucirumab), 96% (nivolumab) and 100% (mepolizumab). In post-analysis, inter-researcher agreement on applicability recommendation of subgroup results was 100%, 94.45% and 100%, respectively. The checklist validation shows a high interindividual agreement of the results, both with respect to the evaluation of the applicability of subgroup analysis and concerning clinical decision-making. What is new and conclusion We have developed the first validated tool for interpretation of subgroup analyses. The checklist contributes to the adoption of homogeneous criteria for subgroup analyses, thereby allowing discussion and evaluation of the effects of a health intervention.