Analysing the analysis CMAJ 1997;156:765 In response to: P. Biron Re: "Management of intermittent claudication with pentoxifylline: meta-analysis of randomized controlled trials," CMAJ 1996;155:1053-9 [abstract / résumé] Biron raises 2 important points concerning the lack of descriptive data reported in 1 of the clinical trials included in our meta-analysis and the less-than-optimal quality of reporting of clinical trials in general. As we indicated in the Discussion of our meta-analysis, "although we attempted to minimize bias, one limitation that persisted was the extraction of data from published trials. There seemed to be little consistency in the type of data reported." In the case of the trial by Porter and associates, we corresponded with the principal author, who provided us with the appropriate data to allow us to make the necessary calculations. Had Biron been systematic in his review of all of the trials we included in the meta-analysis, he would have observed, as we pointed out, that "in more than 25% of the eligible trials standard descriptive statistics were not presented and insufficient data were provided to calculate them." The quality of reporting of randomized controlled trials (RCTs) has been a concern for some time. Several guidelines that describe what needs to be included when reporting a trial have been published.[1,2] In addition, some journals[3] have published checklists of items for assessing RCTs, to be used by authors, reviewers and readers. Other journals[4] have published their policy on the statistical assessment of trials. In general, these efforts have not had their intended effect of improving the quality of reporting of clinical research. Perhaps one of the reasons for this disappointment is that these efforts were not evidence-based. More recent evidence-based approaches appear to be having a positive effect. CMAJ,[5] along with approximately 30 other journals, have either adopted or are seriously considering adopting the consolidated standards of reporting trials -- the CONSORT statement[6] -- which includes a checklist and flow diagram. The checklist consists of 21 items that pertain mainly to the methods, results and discussion of an RCT report and identify key pieces of information necessary to evaluate its internal and external validity. The long-term effects of CONSORT still require evaluation. David Moher, MSc Clinical Epidemiology Unit Ottawa Civic Hospital Loeb Research Institute Ottawa, Ont. References Grant A. Reporting controlled trials. Br J Obstet Gynaecol 1989;96:397-400. Mosteller F, Gilbert JP, McPeek B. Reporting standards and research strategies for controlled trials. Controlled Clin Trials 1980;1:37-58. Gardner MJ, Machin D, Campbell MJ. Use of checklists in assessing the statistical content of medical studies. BMJ 1986;292:810-12. Gore SM, Jones G, Thompson SG. The Lancet's statistical review process: areas for improvement by authors. Lancet 1993;340:100-2. Huston P, Hoey J. CMAJ endorses the CONSORT statement. CMAJ 199;155:1277-9. Begg C, Cho M, Eastwood S, Horton R, Moher D, Olkin I, et al. Improving the quality of reporting of randomized controlled trials: the CONSORT statement. JAMA 1996;276;637-9. Send a letter to the editor responding to this letter Envoyez une lettre à la rédaction au sujet de cette lettre | CMAJ March 15, 1997 (vol 156, no 6) / JAMC le 15 mars 1997 (vol 156, no 6) |