Effect of statins on a wide range of health outcomes: a cohort study validated by comparison with randomized trials

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT • The effect of statins on cardiovascular outcomes is well established. • Effects on numerous other health outcomes have been claimed, but results have been inconsistent. • Previous observational studies may have been affected by selection bias and confounding. WHAT THIS STUDY ADDS • This study was larger and more statistically powerful than the combined total of data from all randomized trials of statins undertaken to date. • The validity of the study is supported by findings for vascular outcomes being comparable to those observed in large randomized controlled trials. • There was little evidence to support effects of statins beyond their established effects on cardiovascular disease. AIMS To assess the effect of statins on a range of health outcomes. METHODS We undertook a population‐based cohort study to assess the effect of statins on a range of health outcomes using a propensity score‐based method to control for differences between people prescribed and not prescribed statins. We validated our design by comparing our results for vascular outcomes with the effects established in large randomized trials. The study was based on the United Kingdom Health Improvement Network database that includes the computerized medical records of over four and a half million patients. RESULTS People who initiated treatment with a statin ( n = 129 288) were compared with a matched sample of 600 241 people who did not initiate treatment, with a median follow‐up period of 4.4 years. Statin use was not associated with an effect on a wide range of outcomes, including infections, fractures, venous thromboembolism, gastrointestinal haemorrhage, or on specific eye, neurological or autoimmune diseases. A protective effect against dementia was observed (hazard ratio 0.80, 99% confidence interval 0.68, 0.95). There was no effect on the risk of cancer even after ≥8 years of follow‐up. The effect sizes for statins on vascular end‐points and mortality were comparable to those observed in large randomized trials, suggesting bias and confounding had been well controlled for. CONCLUSIONS We found little evidence to support wide‐ranging effects of statins on health outcomes beyond their established beneficial effect on vascular disease.