Format

Send to

Choose Destination
J Clin Epidemiol. 2013 Oct;66(10):1082-92. doi: 10.1016/j.jclinepi.2013.05.002. Epub 2013 Jul 10.

A case study of pooled-studies publications indicated potential for both valuable information and bias.

Author information

1
Department for Evidence-based Medicine and Clinical Epidemiology, Danube University Krems, 3500 Krems, Austria. kylie.thaler@donau-uni.ac.at

Abstract

OBJECTIVES:

Pooled-studies publications (PSPs) present statistical analyses of multiple randomized controlled trials without a systematic literature search or critical appraisal. We explored the characteristics of PSPs and their potential impact on a systematic review (SR).

STUDY DESIGN AND SETTING:

We systematically evaluated PSPs excluded from an SR of second-generation antidepressants. We analyzed their basic characteristics, risk of bias, and the effect of new data on review conclusions.

RESULTS:

We identified 57 PSPs containing a median of five trials (range, 2-11) and 1,233 patients (range, 117-2,919). Ninety-six percent of PSPs were industry funded, and 49% of PSPs contained unpublished data. The median number of citations for PSPs was 29 (range, 0-549). Only 7% planned pooling a priori, and 19% combined trials with identical protocols. Fifty-nine percent of PSPs eligible for general efficacy provided no new data. For some subgroups and accompanying symptoms (e.g., anxiety, insomnia, melancholia, fatigue, sex, and race), more than 30% of PSPs presented entirely new data or data that could alter the strength of the evidence available in the SR.

CONCLUSION:

In this case study, PSPs provided new information on subgroups and secondary outcomes; however, guidance for reviewers and development of a system to assess their susceptibility to bias are required.

KEYWORDS:

Antidepressants; Bias; Depression; Pooling; Subgroups; Systematic review

PMID:
23850407
DOI:
10.1016/j.jclinepi.2013.05.002
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center