Systematic reviews provide information not contained in traditional narrative reviewsBMJ 1997; 314 doi: https://doi.org/10.1136/bmj.314.7097.1832 (Published 21 June 1997) Cite this as: BMJ 1997;314:1832
- David Henry, Senior lecturer in clinical pharmacologya
- a Faculty of Medicine and Health Sciences, University of Newcastle, NSW, Australia
Editor—David W Kaufman and Samuel Shapiro make several criticisms of our report on the risks of major gastrointestinal complications during treatment with non-steroidal anti-inflammatory drugs.1 2 Some of these criticisms go to the heart of any attempt to combine data from observational studies.
Kaufman and Shapiro point to the varying quality of the studies included in the meta-analysis and the different definitions of outcome and exposure. No relations were apparent between these factors and the estimates of relative risk reported in …