Influence of prestroke glycemic status on outcomes by age in patients with acute ischemic stroke and diabetes mellitus

This study aimed to explore the association between admission HbA1c and the risk of 1-year vascular outcomes stratified by age group in patients with acute ischemic stroke (AIS) and diabetes mellitus (DM). This study analyzed prospective multicenter data from patients with AIS and DM. Admission HbA1C were categorized as:≤6.0%, 6.1%-7.0%, 7.1%-8.0%, and >8.0%. Age was analyzed in categories:≤55 years, 56-65 years, 66-75 years, 76-85 years, and >85 years. The primary outcome was 1-year composite of stroke, MI, and all-cause mortality. The modifying effect of age on the relationships between HbA1c and 1-year primary outcome was explored by Cox proportional hazards model. A total of 16,077 patients (age 69.0 ± 12.4 years; 59.4% males) were analyzed in this study. Among patients ≤55 years, the hazard ratio (HR) of the 1-year primary outcomes increased with an HbA1C > 8.0% (adjusted HR 1.39[1.13-1.70]). For patients aged 56-65 and 66-75, the highest HRs were observed for an HbA1c of 7.1-8.0% (aHRs; 1.21 [1.01-1.46] and 1.22 [1.05-1.41], respectively). In the 85+ age group, the highest HR occurred for HbA1c ≤ 6.0% (aHR 1.47 [0.98-2.19]). The HbA1c 8.0% showed evident age-dependent heterogeneity in the post hoc HR plots. Our study revealed that in patients with AIS and diabetes under 55, higher admission hbA1c was associated with an increased risk of the 1-year primary outcome, while in patients aged over 85, lower HbA1c value (≤6.0%) may be associated with an increased risk of vascular events. The results of our study suggest the age-stratified, heterogeneous associations between admission HbA1c and 1-year vascular outcomes in patients with AIS and diabetes.