Abstract
BACKGROUND: Global shortages for 3 angiotensin receptor-II blockers (ARBs)-valsartan, losartan, and irbesartan-occurred in 2018-2019 after recalls due to ingredient impurities. Provider-level responses to the ARB shortages in the United States and spillovers to other antihypertensive classes are unknown.
OBJECTIVE: To estimate changes in provider-level prescribing for ARBs and non-ARB antihypertensives up to 18 months after the 2018-2019 recalls and shortages.
RESEARCH DESIGN: National cohort study of prescribers using all-payer pharmacy claims. Mixed interrupted time series models quantified changes in prescribing postshortages and heterogeneous changes by specialty, region, medical school graduation cohort, sex, and level of prerecall prescribing.
PATIENTS AND METHODS: Active providers exposed to the 2018-2019 valsartan, irbesartan, and losartan shortages (defined as top-25th percentile for these drugs in 2017).
MEASURES: Within-class changes in prescribing for ARBs (recalled and nonrecalled). Between-class substitutions to non-ARB antihypertensives (ACE-Is, alpha- and beta-adrenergic blockers, calcium channel blockers, diuretics, and other agents).
RESULTS: Among 138,032 prescribers who met the inclusion criteria, per-prescriber fills for valsartan decreased by 57%-59% after it was recalled in July 2018. We observed concurrent increases for losartan and irbesartan fills and no change in overall ARB prescribing. There were no significant changes in fills for ACE-Is or for other antihypertensives. Absolute decreases in valsartan fills were greatest among providers with higher levels of prescribing at baseline. However, relative changes did not differ by prescriber characteristics.
CONCLUSIONS: In this prescriber level, national study, substitutions to other ARBs mitigated decreases in valsartan fills after it was recalled. There were no spillovers to non-ARB anti-hypertensives. The availability of close substitutes during drug shortages may mitigate gaps in access for prescribers and their patients.