Most meta-analyses of drug interventions have narrow scopes and many focus on specific agents

To assess the extent to which meta-analysis publications of drugs and biologics focus on specific named agents or even only a single agent, and identify characteristics associated with such focus.

We evaluated 499 articles with meta-analyses published in 2010 and estimated how many did not cover all the available comparisons of tested interventions for a given condition (not all-inclusive); focused on specific named agent(s), or focused strictly on comparisons of only one specific active agent vs. placebo/no treatment or different doses/schedules.

Of 499 eligible articles, 403 (80.8%) were not all-inclusive, 214 (42.9%) covered only specific named agent(s), and 74 (14.8%) examined only comparisons with one active agent vs. placebo/no treatment or different doses/schedules. Only 39 articles (7.8%) covered all possible indications for the examined agent(s). After adjusting for type of treatment/field, focus on specific named agent(s) was associated with publication in journal venues (odds ratio [OR]: 1.95; 95% confidence interval [CI]: 1.17-3.26) vs. Cochrane, industry sponsoring (OR: 3.94; 95% CI: 1.66-10.66), and individual patient data analyses (OR: 6.59; 95% CI: 2.24-19.39). Individual patient data analyses primarily (29/34) focused on specific named agent(s).

The scope of meta-analysis publications frequently is narrow and shaped to serve particular agents.