Use of Angiotensin‐Converting Enzyme Inhibitors and Angiotensin Receptor Blockers for Geriatric Ischemic Stroke Patients: Are the Rates Right?

BACKGROUND: Our objective is to estimate the effects associated with higher rates of renin‐angiotensin system antagonists, angiotensin‐converting enzyme inhibitors and angiotensin receptor blockers (ACEI/ARBs), in secondary prevention for geriatric (aged >65 years) patients with new ischemic strokes by chronic kidney disease (CKD) status. METHODS AND RESULTS: The effects of ACEI/ARBs on survival and renal risk were estimated by CKD status using an instrumental variable (IV) estimator. Instruments were based on local area variation in ACEI/ARB use. Data abstracted from charts were used to assess the assumptions underlying the instrumental estimator. ACEI/ARBs were used after stroke by 45.9% and 45.2% of CKD and non‐CKD patients, respectively. ACEI/ARB rate differences across local areas grouped by practice styles were nearly identical for CKD and non‐CKD patients. Higher ACEI/ARB use rates for non‐CKD patients were associated with higher 2‐year survival rates, whereas higher ACEI/ARB use rates for patients with CKD were associated with lower 2‐year survival rates. While the negative survival estimates for patients with CKD were not statistically different from zero, they were statistically lower than the estimates for non‐CKD patients. Confounders abstracted from charts were not associated with the instrumental variable used. CONCLUSIONS: Higher ACEI/ARB use rates had different survival implications for older ischemic stroke patients with and without CKD. ACEI/ARBs appear underused in ischemic stroke patients without CKD as higher use rates were associated with higher 2‐year survival rates. This conclusion is not generalizable to the ischemic stroke patients with CKD, as higher ACEI/ARBS use rates were associated with lower 2‐year survival rates that were statistically lower than the estimates for non‐CKD patients.