Survival Benefits of Statins for Primary Prevention: A Cohort Study

Abstract

Objectives: Estimate the effect of statin prescription on mortality in the population of England and Wales with no previous history of cardiovascular disease.

Methods: Primary care records from The Health Improvement Network 1987-2011 were used. Four cohorts of participants aged 60, 65, 70, or 75 years at baseline included 118,700, 199,574, 247,149, and 194,085 participants; and 1.4, 1.9, 1.8, and 1.1 million person-years of data, respectively. The exposure was any statin prescription at any time before the participant reached the baseline age (60, 65, 70 or 75) and the outcome was all-cause mortality at any age above the baseline age. The hazard of mortality associated with statin prescription was calculated by Cox's proportional hazard regressions, adjusted for sex, year of birth, socioeconomic status, diabetes, antihypertensive medication, hypercholesterolaemia, body mass index, smoking status, and general practice. Participants were grouped by QRISK2 baseline risk of a first cardiovascular event in the next ten years of <10%, 10-19%, or ≥20%.

Results: There was no reduction in all-cause mortality for statin prescription initiated in participants with a QRISK2 score <10% at any baseline age, or in participants aged 60 at baseline in any risk group. Mortality was lower in participants with a QRISK2 score ≥20% if statin prescription had been initiated by age 65 (adjusted hazard ratio (HR) 0.86 (0.79-0.94)), 70 (HR 0.83 (0.79-0.88)), or 75 (HR 0.82 (0.79-0.86)). Mortality reduction was uncertain with a QRISK2 score of 10-19%: the HR was 1.00 (0.91-1.11) for statin prescription by age 65, 0.89 (0.81-0.99) by age 70, or 0.79 (0.52-1.19) by age 75.

Conclusions: The current internationally recommended thresholds for statin therapy for primary prevention of cardiovascular disease in routine practice may be too low and may lead to overtreatment of younger people and those at low risk.

Fig 1. Selection age cohorts.

Four cohorts born between 1920 and 1940 who reached the age of 60, 65, 70, or 75 years between 1987 and 2011 with no previous history of cardiovascular disease.

Fig 2. Unadjusted and adjusted effects of statin prescription on the hazard of mortality by age and cardiovascular risk group.

^a 10-year risk of a first cardiovascular event. ^b lipid-lowering therapy. ^c adjusted for sex, year of birth, socioeconomic status, diabetes, hypercholesterolaemia, blood pressure regulating drugs, body mass index, smoking status, and general practice.