Lowering patients' cholesterolBMJ 1995; 311 doi: https://doi.org/10.1136/bmj.311.7006.690a (Published 09 September 1995) Cite this as: BMJ 1995;311:690
Excluding patients from trials increases uncertainty
- Roger H Jay
- Consultant physician Department of Geriatrics, South Tyneside District Hospital, South Shields, Tyne and Wear NE34 0PL
EDITOR,—In their editorial Michael Oliver and colleagues rightly emphasise the important results of the Scandinavian simvastatin survival study,1 which shows that overall mortality can be reduced by simvastatin in patients with existing coronary artery disease.2 They do not, however, mention the problem of patients with heart failure, who were specifically excluded from the study, presumably on the premise that the mortality in such patients was likely to be determined more by their ventricular function than their serum lipid profile.
Coronary artery bypass grafting produces a similar relative reduction in mortality in patients with normal and abnormal ventricular function.3 Since mortality is higher in those with impaired left ventricular function, the absolute benefit of revascularisation is higher in this group. By analogy, lipid lowering treatment may also confer greater absolute benefit on those with heart failure, making the exclusion of this group from the Scandinavian simvastatin survival study particularly unfortunate.
Thus, according to the principles of evidence based medicine, treatment to reduce mortality after myocardial infarction should be selected according to left ventricular function. If the ventricle is normal we should treat raised cholesterol concentrations with simvastatin. If it is impaired we should use an angiotensin converting enzyme inhibitor, but should we apply the study strictly and ignore the lipids?