Differential Effects of Admission Hemoglobin A1c by Estimated Glomerular Filtration Rate Stages on Mortality in Acute Ischemic Stroke and Diabetes

Abstract

Background: The relationship between admission hemoglobin A(1c) (HbA(1c)) levels, estimated glomerular filtration rate (eGFR) stages, and early outcomes may provide key insights into the need for individualized glycemic control based on kidney function in patients with ischemic stroke and diabetes. Methods: We analyzed data from a multicenter, nationwide, prospective stroke registry in South Korea, including patients with ischemic stroke within 7 days of onset and diabetes. Admission HbA(1c) levels (prestroke glycemic status) were categorized as <6.0%, 6.0% to 7.0%, 7.0% to 8.0%, and >= 8.0%. eGFR stages were classified from stage 1 to stage 5 based on the Kidney Disease: Improving Global Outcomes 2021 guidelines. The primary outcome was 3-month all-cause mortality. Cox proportional hazards models were performed and an interaction term between eGFR stages and HbA(1c) groups was included to evaluate potential effect modification. Results: A total of 27 496 patients (age, 69.6 +/- 11.4 years; men, 60.3%) were included. The 3-month cumulative all-cause mortality rates differed significantly by admission HbA(1c) levels: 8.9% in HbA(1c) <6.0% versus 5.3% in HbA(1c) >= 8.0%. In adjusted analyses, while no association between HbA(1c) <6.0% and mortality was observed among eGFR stages, higher HbA(1c) levels (7.0%-8.0% in eGFR stages 1, 3, and 5, and >= 8.0% in stages 2 and 5) were significantly associated with increased mortality risk. Notably, in stage 4, there was no significant association between HbA(1c) and mortality (P=0.027 for interaction). Conclusions: The association between admission HbA(1c) and 3-month mortality varied among eGFR stages. These findings suggest that eGFR stage may need to be considered when tailoring glycemic control strategies in patients with ischemic stroke and diabetes.