Impact of restrictive prescription plans on heart failure medication use

Background — Prescription plans frequently use restrictive strategies to control drug expenditures. Increased restrictions may reduce access to evidence-based therapy among patients with chronic disease. We sought to evaluate the impact of increased restrictions on medication use among heart failure (HF) patients.

Methods and Results — We conducted a population-based cohort study of administrative data from 3 Canadian provinces. During 1998 to 2001, Quebec (QC) had a minimally restrictive plan, whereas Ontario (ON) and British Columbia (BC) had more restrictive prescription plans. We evaluated drug use at 30 days of discharge stratified by prescription plan. Provincial rates of filled prescriptions for HF drugs in QC, ON, and BC were 62%, 58%, and 47% for angiotensin-converting enzyme inhibitors; 34%, 22%, and 16% for β-blockers; 9%, 5%, and 3% for angiotensin receptor blockers; and 79%, 76%, and 62% for loop diuretics, respectively. In multivariate analyses, patients residing in provinces with restrictive plans were less likely to be prescribed drugs that were restricted, such as β-blockers (odds ratio, 0.53; 95% CI, 0.46 to 0.60; 0.36, 0.29 to 0.44, for ON and BC, respectively) and angiotensin receptor blockers (0.50, 0.45 to 0.56; 0.38, 0.32 to 0.46, for ON and BC, respectively), than drugs with no restrictions, such as loop diuretics (0.81, 0.74 to 0.88; 0.40, 0.36 to 0.45, for ON and BC, respectively) and angiotensin-converting enzyme inhibitors (0.80, 0.75 to 0.86; 0.47, 0.43 to 0.52, for ON and BC, respectively).

Conclusion — Among HF patients, residing in a province with a more restrictive prescription plan may be associated with lower use of restricted HF medications over and above the expected regional differences in HF drug use across provinces.