Objective To evaluate targeting of statin prescribing for primary prevention to those with high cardiovascular disease (CVD) risk.

Design Two cohort studies including the general population and initiators of statins aged 35–74 years.

Setting UK primary care records in the Clinical Practice Research Datalink.

Patients 3.8 million general population patients and 300 914 statin users.

Intervention Statin prescribing.

Main outcome measures Statin prescribing by CVD risk; observed 5-year CVD risks; variability between practices.

Results Statin prescribing increased substantially over time to patients with high 10-year CVD risk (≥20%): 7.0% of these received a statin prior to 2007, and 30.4% in 2007 onwards. Prescribing to patients with low risk (<15%) also increased (from 1.9% to 5.0%). Only about half the patients initiating statin treatment were high risk according to CVD risk score. The 5-year CVD risks, as observed during statin treatment, reduced over calendar time (from 17.0% to 7.1%). There was a large variation between general practices in the percentage of high-risk patients prescribed a statin in 2007 onwards, ranging from 8.2% to 61.5%. For low-risk patients, these varied from 2.1% to 29.1%.

Conclusions There appeared to be substantive overuse in low CVD risk and underuse in high CVD risk (600 000 and 850 000 patients, respectively, in the UK since 2007). There is wide variation between practices in statin prescribing to patients at high CVD risk. There is a clear need for randomised trials for the best strategy to target statin treatment and manage CVD risk for primary prevention.