Borrowing strength from external trials in a meta-analysis

Stat Med. 1996 Dec 30;15(24):2733-49. doi: 10.1002/(SICI)1097-0258(19961230)15:24<2733::AID-SIM562>3.0.CO;2-0.


There exists a variety of situations in which a random effects meta-analysis might be undertaken using a small number of clinical trials. A problem associated with small meta-analyses is estimating the heterogeneity between trials. To overcome this problem, information from other related studies may be incorporated into the meta-analysis. A Bayesian approach to this problem is presented using data from previous meta-analyses in the same therapeutic area to formulate a prior distribution for the heterogeneity. The treatment difference parameters are given non-informative priors. Further, related trials which compare one or other of the treatments of interest with a common third treatment are included in the model to improve inference on both the heterogeneity and the treatment difference. Two approaches to estimating relative efficacy are considered, namely a general parametric approach and a method explicit to binary data. The methodology is illustrated using data from 26 clinical trials which investigate the prevention of cirrhosis using beta-blockers and sclerotherapy. Both sources of external information lead to more precise posterior distributions for all parameters, in particular that representing heterogeneity.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adrenergic beta-Antagonists / therapeutic use
  • Bayes Theorem
  • Data Interpretation, Statistical
  • Gastrointestinal Hemorrhage / prevention & control
  • Humans
  • Likelihood Functions
  • Liver Cirrhosis / complications
  • Meta-Analysis as Topic*
  • Models, Statistical*
  • Multivariate Analysis
  • Odds Ratio
  • Randomized Controlled Trials as Topic / methods*
  • Sclerotherapy


  • Adrenergic beta-Antagonists