Abstract 3896: A Restrictive Prescription Policy Contributes to Underutilization of Angiotensin-Receptor-Blockers Among Heart Failure Patients Not Receiving ACE-inhibitors
Background: Evaluating the effects of different prescription policies could provide useful information for designing a Medicare drug program. In Canada, during the late 1990s, British Columbia (BC) had a restrictive policy that limited the use of Angiotensin Receptor Blockers (ARBs) for CHF patients whereas Quebec (QC) had no such policy. We sought to determine how this policy affected the use of ARBs among all CHF patients and those not receiving ACE-inhibitors (“ACE non-users”) in QC and BC and whether differences in ARB use were associated with adverse outcomes.
Methods and Results: Using administrative databases, we monitored 32 738 elderly (age ≥ 65) patients discharged after a first admission for CHF between 1998–2001 from Quebec and British Columbia, and studied the discharge prescriptions within 30 days for CHF medications among all CHF patients and ACE non-users (n = 14 260). ACE non-users were defined as patients not receiving ACE-inhibitors within the first 30 days after CHF discharge. Rates of ARB use for QC and BC, among all CHF patients were 11% and 3%; and among ACE non-users, were 24% and 5%, respectively (p<0.05 for all comparisons). Multivariate analysis demonstrated that among all CHF patients ARB use was higher in QC (OR 3.1, 95% CI 2.8–3.4). These effects were magnified (OR 4.5, CI 4.0–5.0) among ACE non-users. Similar trends were seen for other CHF therapies but the largest differences were seen for ARBs. Adjustments for covariates (age, comorbidity, intervention, treating physician) did not significantly alter these findings. ACE non-users had a higher 1 year risk adjusted mortality in BC (HR 1.10, 95% CI 1.02–1.18) where ARB use was limited by policy. ARB use was associated with lower mortality (HR 0.72, CI 0.62–0.84) among ACE non-users.
Conclusions: Among all CHF patients, ARB use was lower among patients with a restrictive provincial prescription policy. Among ACE non-users, who likely have an indication for ARBs, these effects are magnified and are associated with increased mortality. Our results suggest that a restrictive prescription policy contributes to the underutilization of ARBs which is associated with adverse outcomes among CHF patients.