Table 2.

Checklist for assessing credibility of subgroup analyses [22]

Design Is the subgroup variable a characteristic measured at baseline or after randomization? Is the effect suggested by comparisons within rather than between studies? Was the hypothesis specified a priori? Was the direction of the subgroup effect specified a priori? Was the subgroup effect one of a small number of hypothesized effects tested? Analysis Does the interaction test suggest a low likelihood that chance explains the apparent subgroup effect? Is the significant subgroup effect independent? Context Is the size of the subgroup effect large? Is the interaction consistent across studies? Is the interaction consistent across closely related outcomes within the study? Is there indirect evidence that supports the hypothesized interaction (biological rationale)?