Interpreting meta-analysis according to the adequacy of sample size. An example using isoniazid chemoprophylaxis for tuberculosis in purified protein derivative negative HIV-infected individuals

Original Research

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Authors: Kristian Thorlund, Aranka Anema, Edward Mills

Published Date April 2010 Volume 2010:2 Pages 57 - 66

DOI: http://dx.doi.org/10.2147/CLEP.S9242

Kristian Thorlund^1,2, Aranka Anema³, Edward Mills⁴

¹Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada; ²The Copenhagen Trial Unit, Centre for Clinical Intervention Research, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark; ³British Columbia Centre for Excellence in HIV/AIDS, University of British Columbia, Vancouver, British Columbia, Canada; 4Faculty of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada

Objective: To illustrate the utility of statistical monitoring boundaries in meta-analysis, and provide a framework in which meta-analysis can be interpreted according to the adequacy of sample size. To propose a simple method for determining how many patients need to be randomized in a future trial before a meta-analysis can be deemed conclusive.

Study design and setting: Prospective meta-analysis of randomized clinical trials (RCTs) that evaluated the effectiveness of isoniazid chemoprophylaxis versus placebo for preventing the incidence of tuberculosis disease among human immunodeficiency virus (HIV)-positive individuals testing purified protein derivative negative. Assessment of meta-analysis precision using trial sequential analysis (TSA) with LanDeMets monitoring boundaries. Sample size determination for a future trials to make the meta-analysis conclusive according to the thresholds set by the monitoring boundaries.

Results: The meta-analysis included nine trials comprising 2,911 trial participants and yielded a relative risk of 0.74 (95% CI, 0.53–1.04, P = 0.082, I² = 0%). To deem the meta-analysis conclusive according to the thresholds set by the monitoring boundaries, a future RCT would need to randomize 3,800 participants.

Conclusion: Statistical monitoring boundaries provide a framework for interpreting meta-analysis according to the adequacy of sample size and project the required sample size for a future RCT to make a meta-analysis conclusive.

Keywords: meta-analysis, trial sequential analysis (TSA), randomized clinical trials (RCTs), isoniazid chemoprophylaxis, adequacy of sample size, human immunodeficiency virus (HIV), tuberculosis, purified protein derivative negative

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