BACKGROUND: A recent study suggested that results of single-center trials are frequently contradicted when similar trials are performed in multicenter settings. PURPOSE: To perform a meta-epidemiologic study to evaluate whether estimates of treatment effect differ between single-center and multicenter randomized, controlled trials (RCTs). DATA SOURCES: MEDLINE was searched via PubMed for meta-analyses of RCTs with binary outcomes that were published between August 2008 and January 2009 and in the first 6 months of 2010 in the 10 leading journals of each medical specialty. One issue of the Cochrane Database of Systematic Reviews was also searched. STUDY SELECTION: All individual RCTs included in the meta-analyses were selected. DATA EXTRACTION: Data were extracted and their quality was assessed by use of the risk of bias tool of the Cochrane Collaboration. DATA SYNTHESIS: The primary outcome was the ratio of odds ratios (ROR), used to quantify the difference in estimated intervention effect between single-center and multicenter RCTs. An ROR less than 1 would indicate larger estimates of the intervention effect in single-center trials. Sensitivity analyses were performed with adjustment for sample size, risk of bias within RCTs, and variance of the log odds ratio to take publication bias into account. Forty-eight meta-analyses were selected, including 421 RCTs (223 were single-center and 198 were multicenter). Single-center RCTs showed a larger intervention effect than did multicenter RCTs (combined ROR, 0.73 [95% CI, 0.64 to 0.83]), with low heterogeneity across individual meta-analyses (I(2) = 12.0%; P = 0.24). Adjustment for sample size yielded consistent results (ROR, 0.85 [CI, 0.74 to 0.97]), as did adjustment for risk of bias within RCTs, such as allocation concealment (ROR, 0.76 [CI, 0.67 to 0.86]), and variance of log odds ratio (ROR, 0.83 [CI, 0.72 to 0.96]). LIMITATION: Despite sensitivity analyses, meta-confounding cannot be fully excluded. CONCLUSION: Single-center RCTs showed larger treatment effects than did multicenter RCTs, a finding that was consistent in all sensitivity analyses. These results suggest that this item should be considered when the results of RCTs and meta-analyses are interpreted. PRIMARY FUNDING SOURCE: Academic grant Recherche sur la Recherche from the Délégation Interrégionale à la Recherche Clinique (DIRC), Ile de France, Assistance Publique-Hôpitaux de Paris (APHP).
BACKGROUND: A recent study suggested that results of single-center trials are frequently contradicted when similar trials are performed in multicenter settings. PURPOSE: To perform a meta-epidemiologic study to evaluate whether estimates of treatment effect differ between single-center and multicenter randomized, controlled trials (RCTs). DATA SOURCES: MEDLINE was searched via PubMed for meta-analyses of RCTs with binary outcomes that were published between August 2008 and January 2009 and in the first 6 months of 2010 in the 10 leading journals of each medical specialty. One issue of the Cochrane Database of Systematic Reviews was also searched. STUDY SELECTION: All individual RCTs included in the meta-analyses were selected. DATA EXTRACTION: Data were extracted and their quality was assessed by use of the risk of bias tool of the Cochrane Collaboration. DATA SYNTHESIS: The primary outcome was the ratio of odds ratios (ROR), used to quantify the difference in estimated intervention effect between single-center and multicenter RCTs. An ROR less than 1 would indicate larger estimates of the intervention effect in single-center trials. Sensitivity analyses were performed with adjustment for sample size, risk of bias within RCTs, and variance of the log odds ratio to take publication bias into account. Forty-eight meta-analyses were selected, including 421 RCTs (223 were single-center and 198 were multicenter). Single-center RCTs showed a larger intervention effect than did multicenter RCTs (combined ROR, 0.73 [95% CI, 0.64 to 0.83]), with low heterogeneity across individual meta-analyses (I(2) = 12.0%; P = 0.24). Adjustment for sample size yielded consistent results (ROR, 0.85 [CI, 0.74 to 0.97]), as did adjustment for risk of bias within RCTs, such as allocation concealment (ROR, 0.76 [CI, 0.67 to 0.86]), and variance of log odds ratio (ROR, 0.83 [CI, 0.72 to 0.96]). LIMITATION: Despite sensitivity analyses, meta-confounding cannot be fully excluded. CONCLUSION: Single-center RCTs showed larger treatment effects than did multicenter RCTs, a finding that was consistent in all sensitivity analyses. These results suggest that this item should be considered when the results of RCTs and meta-analyses are interpreted. PRIMARY FUNDING SOURCE: Academic grant Recherche sur la Recherche from the Délégation Interrégionale à la Recherche Clinique (DIRC), Ile de France, Assistance Publique-Hôpitaux de Paris (APHP).
Authors: Elizabeth K Stevenson; Amanda R Rubenstein; Gregory T Radin; Renda Soylemez Wiener; Allan J Walkey Journal: Crit Care Med Date: 2014-03 Impact factor: 7.598
Authors: James D Lewis; Lindsey Albenberg; Dale Lee; Mario Kratz; Klaus Gottlieb; Walter Reinisch Journal: Inflamm Bowel Dis Date: 2017-02 Impact factor: 5.325