Physician follow-up and provider continuity are associated with long-term medication adherence: a study of the dynamics of statin use

Abstract

Background: Many patients who initiate statin (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor) therapy discontinue treatment within 1 year. We sought to estimate the rate at which patients reinitiate treatment after long periods of nonadherence and to determine whether reinitiation of treatment is linked to potentially modifiable factors such as physician visits, cholesterol testing, or other encounters with the health care system.

Methods: We studied new users of statins in British Columbia, Canada, who initiated treatment between January 1, 1997, and June 30, 2004, and who had an extended period of nonadherence, defined as at least 90 days after the completion of 1 prescription in which no refill for any statin medication was obtained. Survival analysis was used to estimate the rate of reinitiation of statin therapy. Case-crossover analysis was used to evaluate the predictors of reinitiation.

Results: We identified 239 911 new users of statins, of whom 129 167 (53.8%) had a period of nonadherence that lasted for at least 90 days. Of these patients, an estimated 48% restarted treatment within 1 year and 60% restarted treatment within 2 years. Case-crossover analysis revealed events that were associated with a return to adherence, including visits with the physician who initiated the statin regimen (odds ratio [OR], 6.1; 95% confidence interval [CI], 5.9-6.3), a visit with another physician (OR, 2.9; 95% CI, 2.8-3.0), and a cholesterol test (OR, 1.5; 95% CI, 1.4-1.5). Incident myocardial infarction (OR, 12.2; 95% CI, 8.9-16.9) and other cardiovascular disease-related hospitalizations (OR, 3.6; 95% CI, 3.1-4.3) were also strong predictors of reinitiation of treatment.

Conclusions: Physicians should be aware that statin use is dynamic and that many patients have long periods of nonadherence. A follow-up visit with the physician who wrote the initial statin prescription and having a cholesterol test predicted reinitiation of statin therapy. Our results suggest that continuity of care combined with increased follow-up and cholesterol testing could promote long-term adherence by shortening or eliminating long gaps in statin use. This hypothesis should be confirmed in a randomized experiment.