Interpretation of trials with drugs and devices; a double standard?

Interpretation of trials with drugs and devices; a double standard? Recently, results have been presented of two major trials which, appropriately, received considerable attention in both the professional and lay press. The West of Scotland Coronary Prevention study (WOSCOP) demonstrated a reduction of coronary events at 5-year follow-up through treatment with a cholesterol lowering drug (pravastatin), and the Bypass surgery Angioplasty Revascularisation Investigation (BARI) reported a similar outcome with coronary angioplasty and bypass surgery after 5 years' 1 ' 21. The interpretation of the results, as presented by the investigators at the 1995 sessions of the American Heart Association, suggests that different standards are applied to studies with drugs and devices. The West of Scotland study randomized 6595 male subjects without previous myocardial infarction and with serum LDL levels between 4-5 and 60 mmol. 1 ~ ' to treatment with pravastatin (40 mg) or placebo' 1 '. After average follow up of 4-9 years, approximately 70% of the participants were using study medication. The primary endpoint of definite non-fatal myocardial infarction or death from coronary heart disease was reduced by pravastatin from 7-9% to 5-5% at 5 years. This 31% relative reduction was statistically significant; 95% confidence interval 17-43%, / > <0-001. Furthermore, reductions were observed in coronary revascularization procedures (2-5% vs 1-7%, / > =0009) and in total mortality at 5 years (4-1% vs 3-2%, P=0051, see Table 1). The findings were consistent among many subgroups. The results of the West of Scotland study are consistent with those of the recently published Scandinavian Simvastatin Survival Study (4S) in 4444 patients with documented coronary artery disease' 31. In 4S, total mortality was reduced after 6 years' treatment with simvastatin from 12-4% to 8-7%. This corresponds to a relative mortality reduction of 30%, a 95% confidence interval of 15-42%, and P=00003. Furthermore, a combined analysis of 14 angiographic studies revealed retardation of progression and in some of the patients regression of coronary lesions, associated with a 22% relative reduction of mortality and reinfarction after 2 to 5 years' 41. A pooled analysis of other smaller studies with pravastatin yielded similar reduction of cardiovascular events' 51. The Bypass surgery Angioplasty Revascularisation Investigation (BARI) enrolled 1829 patients with angina pectoris or documented myocardial ischaemia during exercise and multivessel coronary artery disease. These patients were selected from approximately 12 530 candidates for bypass surgery (CABG) of whom 4530 were eligible for angioplasty (PTCA). Their …