Continuation of Statin Treatment and All-Cause Mortality A Population-Based Cohort Study

Background: The beneficial effects of statins on cardiovascular mortality in secondary prevention have been established in several long-term, placebo-controlled trials. However, the value of statin therapy in reduction of overall mortality in patients without coronary heart disease (CHD) is questionable. This study evaluated the effect of statin therapy in subjects with no indication of cardiovascular disease (primary prevention) and patients with known CHD (secondary prevention). Methods: This retrospective cohort study included 229 918 adult enrollees in a health maintenance organization in Israel who initiated statin treatment from 1998 through 2006 (mean age, 57.6 years; 50.8% female). Proportion of days covered (PDC) with statins was measured by the number of dispensed statin prescriptions during the interval between the date of the first statin prescription and the end of follow-up. Results: During a mean of 4.0 and 5.0 years of follow-up, there were 4259 and 8906 deaths among the primary prevention and secondary prevention cohorts, respectively. In both cohorts, continuity of treatment with statins (PDC, > 90%) conferred at least a 45% reduction in risk of death compared with patients with a PDC of less than 10%. A stronger risk reduction was calculated among patients with high baseline low-density lipoprotein cholesterol level and patients initially treated with high-efficacy statins. Conclusions: Better continuity of statin treatment provided an ongoing reduction in mortality among patients with and without a known history of CHD. The observed benefits from statins were greater than expected from randomized clinical trials.