Persistence with lipid-lowering therapy: influence of the type of lipid-lowering agent and drug benefit plan option in elderly patients.

Abstract

OBJECTIVE: To determine the effects of lipid-lowering agent (LLA) class and drug plan design option on persistence with LLAs among elderly patients enrolled in a managed care plan. METHODS: A retrospective cohort study was conducted among 310 older adult members enrolled in a health maintenance organization operating in New England who were dispensed an LLA between July 1, 1994, and June 30, 1996. Survival analysis was used to examine differences in discontinuation of LLAs between different classes of LLAs and drug benefit plans as well as patient sex, age, prior hospitalization for coronary heart disease (CHD), hypertension, diabetes mellitus, and the number of other medications. RESULTS: The overall LLA discontinuation rate increased with time from 18% (95% confidence interval [CI], 13.8%-22.4%) at 6 months to 46% (95% CI, 39.7%- 52.5%) at 12 months and 66% (95% CI, 59.2%-73.0%) at 18 months. The likelihood of discontinuation increased from 54% (95% CI, 44.8%-63.6%) at 12 months to 77% (95% CI, 67.5%-85.5%) at 18 months in nonstatin users and from 39% (95% CI, 30.4%-47.6%) at 12 months to 57 % (95% CI, 47.3%-66.9%) at 18 months in statin users (P = 0.001). Among patients prescribed a statin at initial prescription (n = 182), the 12-month discontinuation rates were 33% (95% CI, 23.0%-43.6%) for those with full drug benefit coverage and 50% (95% CI, 34.8%-65.1%) for those with 1,000 dollars per year maximum coverage, while the 21-month discontinuation rates were 60% (95% CI, 46.3%-72.9%) for those with full coverage and 86% (95% CI, 73.7%-98.7%) for those with 1,000 dollars per year maximum coverage (P = 0.023). Adjusting for plan design and hypertension, statin users were less likely to discontinue compared with users of other LLAs (rate ratio [RR] = 0.58; 95% CI, 0.40-0.82; P = 0.002). Among patients dispensed a statin, full-coverage members were less likely to discontinue compared with members having an annual 1,000 dollars maximum drug coverage, adjusting for diabetes and hypertension (RR = 0.58; 95% CI, 0.34-0.98; P = 0.041). This finding was among a small sample after subanalyses, and further research is warranted. Plan design was not determined to be significantly associated with discontinuation of other LLAs. CONCLUSIONS: Our findings suggest that persistence with LLAs is low among older patients regardless of scope of drug benefit coverage or the drug class. Addressing the challenges of maintaining adherence to prescribed therapeutic regimens in the elderly will require a multifaceted approach; deficiencies will not be eliminated simply through the provision of prescription drug benefit coverage.