Abstract
BACKGROUND: Resting heart rate is a potent predictor of various renal outcomes. However, the decline rate of renal function in ischemic stroke patients is not well defined. We tested the association of heart rate with estimated eGFR decline and the composite renal outcomes in patients with recent ischemic stroke. METHODS: The data of 9366 patients with ischemic stroke with an eGFR of ≥30 mL/min/1.73 m(2) were retrieved from the Chang Gung Research Database. Mean initial in-hospital heart rates were averaged and categorized into 10-beats-per-minute (bpm) increments. The outcomes were the annualized change in eGFR across the heart rate subgroups and composite renal outcomes, namely a ≥40% sustained decline in eGFR, end-stage renal disease, or renal death. Generalized estimating equation models were used to determine the annualized change in eGFR and Cox proportional hazards regression models were used to estimate the relative hazard of composite renal outcomes by referencing the subgroup with a heart rate of <60 bpm. RESULTS: The annual eGFR decline in the patients with a mean heart rate of <60, 60-69, 70-79, 80-89, and ≥90 bpm was 2.12, 2.49, 2.83, 3.35, and 3.90 mL/min/1.73 m(2), respectively. Compared with the reference group, the adjusted hazard ratios for composite renal outcomes were 1.17 [95% confidence interval (CI), 0.89-1.53), 1.54 (95% CI, 1.19-2.00), 1.72 (95% CI, 1.30-2.28), and 1.84 (95% CI, 1.29-2.54] for the patients with a heart rate of 60-69, 70-79, 80-89, and ≥90 bpm, respectively. In the subgroup analysis, the associations between higher heart rate and both eGFR decline and composite renal outcomes were more evident and statistically significant in patients without atrial fibrillation. CONCLUSIONS: A higher heart rate is associated with a faster rate of eGFR decline and an increased risk of composite renal outcomes after ischemic stroke, particularly in patients without atrial fibrillation. These results underscore the importance of heart rate monitoring and management in ischemic stroke patients in sinus rhythm to potentially mitigate renal function decline. Further studies are needed to explore this relationship in patients with atrial fibrillation and across different ethnic groups.