JAMA版医学文献ユーザーズガイド(第2版)の20.4章は「いつサブグループ解析を信頼するか」で、サブグループ解析の結果が妥当なものかを判断するための7つの基準がよく知られています。
GRADEシステムにおいては、body of evidenceの非一貫性がある場合に、サブグループ別にエビデンスを提示する必要があり得ます。
上記の従来の7基準に、新たに4項目が加えられた基準(以下の蛍光部分)が発表されています。
Is a subgroup effect believable? Updating criteria to evaluate the credibility of subgroup analyses
BMJ 2010;340:c117
Criteria to assess the credibility of subgroup analyses
Design
- Is the subgroup variable a characteristic measured at baseline or after randomisation?*
- 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 hypothesised 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 hypothesised interaction (biological rationale)?
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*New criteria