Letter by Colquhoun et al Regarding Article “Effect Size Estimates of Lifestyle and Dietary Changes on All-Cause Mortality in Coronary Artery Disease Patients: A Systematic Review”
To the Editor:
The recent paper by Iestra et al in Circulation1 was an excellent review of various lifestyle measures that have been assessed with regard to decreased cardiovascular end points and mortality rates. The review by Iestra et al was based on a PubMed search of relevant research published between 1966 and May 2004. Unfortunately, the only weight loss trial found was one from R.B. Singh published in 1992.2 Additionally, in Table 2, “Studies on Lifestyle and Dietary Factors and All-Causes Mortality in Coronary Artery Disease Patients,” under “Combined Lifestyle Factor Studies,” only 2 Singh trials2,3 are presented of the 4 studies that were analyzed. This is highly problematic as recent material has suggested Singh’s research may be fraudulent, with his work being the subject of critical editorials in The Lancet4,5 and British Medical Journal6 last year. Clearly, lifestyle intervention has enormous potential in preventing vascular disease; however, in this case the clinical trial database is less than optimal. Rigorous, randomized, controlled trials that are monitored according to US Food and Drug Administration standards are needed, as exemplified by the modern era of drug outcome trials, so the wider community can be reassured of the validity of the results and their subsequent utilization in systematic reviews and meta-analyses.
David Colquhoun has received research support from AstraZeneca, Pfizer, Merck Sharpe Dohme, Fornier Pharma, Solvay, Schering-Plough, Bristol-Myers Squibb, Abbott, Sanofi, and Boehringer Ingelheim. He has been on the speakers’ bureau of, received honoraria from, and served as a consultant for AstraZeneca, Pfizer, Merck Sharpe Dohme, Abbott, Servier, and Fornier Pharma. Dr Kostner has received research grants from the University of Queensland and the Princess Alexandra Hospital. He has served on the speakers’ bureau of and received honoraria from AstraZeneca and has received honoraria from Core Research Group. Antonio Ferreira-Jardim has nothing to disclose.
Iestra JA, Kromhout D, van der Schouw YT, Grobbee DE, Boshuizen HC, and van Staveren WA. Effect size estimates of lifestyle and dietary changes on all-cause mortality in coronary artery disease patients: a systematic review. Circulation. 2005; 112: 924–934.
Singh RB, Rastogi SS, Verma R, Laxmi B, Singh R, Ghosh S, Niaz MA. Randomised controlled trial of cardioprotective diet in patients with recent acute myocardial infarction: results of one year follow up. BMJ. 1992; 304: 1015–1019.
Singh RB, Dubnov G, Niaz MA, Ghosh S, Singh R, Rastogi SS, Manor O, Pella D, Berry EM. Effect of an Indo-Mediterranean diet on progression of coronary artery disease in high risk patients (Indo-Mediterranean Diet Heart Study): a randomised single-blind trial. Lancet. 2002; 360: 1455–1461.
White C. Suspected research fraud: difficulties of getting at the truth. BMJ. 2005; 331: 281–288.