Discontinuation and restarting in patients on statin treatment: prospective open cohort study using a primary care database

Abstract

Objectives: To estimate rates of discontinuation and restarting of statins, and to identify patient characteristics associated with either discontinuation or restarting.

Design: Prospective open cohort study.

Setting: 664 general practices contributing to the Clinical Practice Research Datalink in the United Kingdom. Data extracted in October 2014.

Participants: Incident statin users aged 25-84 years identified between January 2002 and September 2013. Patients with statin prescriptions divided into two groups: primary prevention and secondary prevention (those already diagnosed with cardiovascular disease). Patients with statin prescriptions in the 12 months before study entry were excluded.

Main outcome measures: Discontinuation of statin treatment (first 90 day gap after the estimated end date of a statin prescription), and restarting statin treatment for those who discontinued (defined as any subsequent prescription between discontinuation and study end).

Results: Of 431 023 patients prescribed statins as primary prevention with a median follow-up time of 137 weeks, 47% (n=204 622) discontinued treatment and 72% (n=147 305) of those who discontinued restarted. Of 139 314 patients prescribed statins as secondary prevention with median follow-up time of 182 weeks, 41% (n=57 791) discontinued treatment and 75% (43 211) of those who discontinued restarted. Younger patients (aged ≤50 years), older patients (≥75 years), women, and patients with chronic liver disease were more likely to discontinue statins and less likely to restart. However, patients in ethnic minority groups, current smokers, and patients with type 1 diabetes were more likely to discontinue treatment but then were more likely to restart, whereas patients with hypertension and type 2 diabetes were less likely to discontinue treatment and more likely to restart if they did discontinue. These results were mainly consistent in the primary prevention and secondary prevention groups.

Conclusions: Although a large proportion of statin users discontinue, many of them restart. For many patient groups previously considered as "stoppers," the problem of statin treatment "stopping" could be part of the wider issue of poor adherence. Identification of patient groups associated with completely stopping or stop-starting behaviour has positive implications for patients and doctors as well as suggesting areas for future research.

Fig 1 Flow chart of study patients discontinuing and restarting statin treatment, based on CPRD data

Fig 2 Patients who discontinued statin treatment, based on CPRD data, October 2014

Fig 3 Patients who restarted statins after discontinuation, based on CPRD data, October 2014

Fig 4 Risk of discontinuation of statin treatment, as shown by fractional polynomials terms. Terms are for age (hazard ratios compared with age 60 years), body mass index (hazard ratios compared with body mass index 25), high density lipoprotein (HDL):total cholesterol ratio (hazard ratios compared with ratio 3.5), and systolic blood pressure (hazard ratios compared with 130 mm Hg)

Fig 5 Risk of restarting statin treatment, as shown by fractional polynomials terms. Terms are for age (hazard ratios compared with age 60 years), body mass index (hazard ratios compared with body mass index 25), high density lipoprotein (HDL):total cholesterol ratio (compared with ratio 3.5), and systolic blood pressure (compared with 130 mm Hg)