Exaggerated report of benefits in a flawed long term statin treatment study

The BMJ reports on the findings of a study on long term (20 year) treatment with a statin in the WOSCOPS trial by Vallejo-Vaz et al.12 The news article and publication report that, in this primary prevention trial, pravastatin reduced deaths from heart disease by 28% in men with high levels of LDL cholesterol. But 28% is the relative risk reduction; the more clinically relevant measure of drug effectiveness is absolute risk reduction, which was only 2.3% between treated and untreated groups. Both the study and the news story follow a pattern of focusing on the more dramatic, but misleading, relative risk statistic in statin trials.3

To make matters worse, the reported beneficial effects of long term statin use are not only minuscule but also unreliable. After the five year trial finished, the majority of people in the treatment group stopped taking their statin, and one third of the people in the placebo group had started statin treatment. Furthermore, the investigators did not monitor which participants were on a statin over the 15 years of follow-up. The only thing we can be certain of is that the majority of people in both groups were not on a statin in the 15 year follow-up period. We can’t be confident that the purported benefits of long term statin treatment reported by Vallejo-Vaz et al are valid.

Despite the sensational headlines of The BMJ’s news story and the media attention this follow-up study generated, the study was so flawed in its methodology that it provided nothing of value in terms of guidance for clinicians seeking high calibre research on the long term effects of statins on coronary outcomes.