PERSISTENCE OF USE OF LIPID-LOWERING MEDICATIONS - A CROSS-NATIONAL-STUDY

Context.-Although clinical trials have demonstrated the benefits of li pid-lowering therapy, little is known about how these drugs are prescr ibed or used in the general population. Objective.-To estimate predict ors of persistence with therapy for lipid-lowering drug regimens in ty pical populations of patients in the United States and Canada. Design. -A cohort study defining all prescriptions filled for lipid-lowering d rugs during 1 year, as well as patients' demographic and clinical char acteristics. Setting.-New Jersey's Medicaid and Pharmacy Assistance fo r the Aged and Disabled programs and Quebec's provincial medical care program. Patients.-All continuously enrolled patients older than 65 ye ars who filled 1 or more prescriptions for lipid-lowering drugs (N = 5 611 in the US programs, and N = 1676 drawn from a 10% sample in Quebec ). Main Outcome Measures.-Proportion of days during the study year for which patients had filled prescriptions for lipid-lowering drugs; pre dictors of good vs poor persistence with therapy. Results.-In both pop ulations, patients failed to fill prescriptions for lipid-lowering dru gs for about 40% of the study year. Persistence rates with 3-hydroxy-3 -methylglutaryl coenzyme A reductase inhibitors were significantly hig her than those seen with cholestyramine (64.3% vs 36.6% of days with d rug available, respectively). Patients with hypertension, diabetes, or coronary artery disease had significantly higher rates of persistence with lipid-lowering regimens. In New Jersey, multivariable analysis i ndicated that the poorest patients (those enrolled in Medicaid) had lo wer rates of drug use than less indigent patients (those enrolled in P harmacy Assistance for the Aged and Disabled) after adjusting for poss ible confounders, despite virtually complete drug coverage in both pro grams. When rates of use were measured in the US population for the 5 years following the study year, only 52% of surviving patients who wer e initially prescribed lipid-lowering drugs were still filling prescri ptions for this drug class. Conclusion.-In all populations studied, pa tients who were prescribed lipid-lowering drug regimens remained witho ut filled prescriptions for over a third of the study year on average. Rates of persistence varied substantially with choice of agent prescr ibed, comorbidity, and socioeconomic status, despite universal coverag e of prescription drug costs. After 5 years, about half of the survivi ng original cohort in the United States had stopped using lipid-loweri ng therapy altogether.