TY - JOUR
T1 - Systematic reviewers neglect bias that results from trials stopped early for benefit
AU - Bassler, Dirk
AU - Ferreira-Gonzalez, Ignacio
AU - Briel, Matthias
AU - Cook, Deborah J.
AU - Devereaux, P. J.
AU - Heels-Ansdell, Diane
AU - Kirpalani, Haresh
AU - Meade, Maureen O.
AU - Montori, Victor M.
AU - Rozenberg, Anna
AU - Schünemann, Holger J.
AU - Guyatt, Gordon H.
N1 - Funding Information:
Dr. Ferreira is supported by Carlos III Spanish Institute of Health Research Fellowship Award (FIS). Dr. Briel is supported by the Swiss National Science Foundation. Dr. Montori is a Mayo Foundation Scholar. Dr. P.J. Devereaux is supported by a Canadian Institutes of Health Research, New Investigator Award. Dr. Cook is a Research Chair of the Canadian Institutes for Health Research.
PY - 2007/9
Y1 - 2007/9
N2 - Objective: To examine how authors of systematic reviews that include randomized clinical trials (RCTs) that are stopped early for benefit (truncated RCTs-tRCTs) address the potential for overestimation of treatment effects and to determine the weight of the tRCTs on pooled results. Study Design and Setting: We searched the Cochrane Library and MEDLINE and evaluated systematic reviews that include at least one tRCT. We documented approaches that authors used to address potential overestimates of treatment effect introduced by including tRCTs. We assessed the impact of tRCTs in meta-analyses on the outcomes that led to their early termination. Results: Of 96 systematic reviews that included at least one tRCT, 44 (46%) included >1 tRCT, 68 (71%) did not mention truncation at all, and 2 (2%) documented early stopping for benefit as a criterion for methodological quality. Of 47 meta-analyses in which authors reported, or we could calculate the contribution of the tRCTs to the pooled result, the tRCTs contributed more than 40% of the weight in 16/47 (34%). Conclusion: Most systematic reviews and meta-analyses including tRCTs fail to consider the possible overestimates of effect that may result from early stopping for benefit. We recommend safeguards that address this possibility.
AB - Objective: To examine how authors of systematic reviews that include randomized clinical trials (RCTs) that are stopped early for benefit (truncated RCTs-tRCTs) address the potential for overestimation of treatment effects and to determine the weight of the tRCTs on pooled results. Study Design and Setting: We searched the Cochrane Library and MEDLINE and evaluated systematic reviews that include at least one tRCT. We documented approaches that authors used to address potential overestimates of treatment effect introduced by including tRCTs. We assessed the impact of tRCTs in meta-analyses on the outcomes that led to their early termination. Results: Of 96 systematic reviews that included at least one tRCT, 44 (46%) included >1 tRCT, 68 (71%) did not mention truncation at all, and 2 (2%) documented early stopping for benefit as a criterion for methodological quality. Of 47 meta-analyses in which authors reported, or we could calculate the contribution of the tRCTs to the pooled result, the tRCTs contributed more than 40% of the weight in 16/47 (34%). Conclusion: Most systematic reviews and meta-analyses including tRCTs fail to consider the possible overestimates of effect that may result from early stopping for benefit. We recommend safeguards that address this possibility.
KW - Bias
KW - Clinical trial methodology
KW - Heterogeneity in meta-analysis
KW - Stopping rules
KW - Systematic reviews and meta-analysis
KW - Truncation of studies
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U2 - 10.1016/j.jclinepi.2006.12.006
DO - 10.1016/j.jclinepi.2006.12.006
M3 - Review article
C2 - 17689802
AN - SCOPUS:34547584099
SN - 0895-4356
VL - 60
SP - 869
EP - 873
JO - Journal of Clinical Epidemiology
JF - Journal of Clinical Epidemiology
IS - 9
ER -