Association of HbA1c and comorbidities on stroke severity: insights from a cross-sectional analysis in a tertiary hospital

Introduction Elevated HbA1c levels, in combination with comorbidities such as diabetes and hypertension, have been linked to increased stroke severity, poorer functional recovery, and higher mortality. However, the predictive value of HbA1c—a marker of long-term glycemic control—for acute stroke severity remains unclear. This study investigated the relationship between admission HbA1c levels and comorbidities on stroke severity in patients presenting to a tertiary care center. Methods We conducted a retrospective cross-sectional study at King Abdulaziz Medical City in Riyadh, Saudi Arabia, including 672 adult patients with acute ischemic stroke between January 2016 and January 2023. Patients were stratified into three groups based on admission HbA1c (≤6.4%, 6.5–7.9%, ≥8%). Stroke severity was assessed using the National Institutes of Health Stroke Scale (NIHSS) at admission and discharge. Results A total of 672 patients were included (mean age 63.7 ± 13.2 years; 68.6% male). At admission, 49.9% had mild, 42.3% moderate, and 7.9% severe strokes, with no significant association between HbA1c and stroke severity ( p = 0.177). Although higher HbA1c levels were associated with vascular comorbidities in bivariate analysis, only LDL (OR = 1.06, 95% CI: 1.00–1.12; p = 0.045) and atrial fibrillation (OR = 0.73, 95% CI: 0.58–0.91; p = 0.005) remained significant after adjustment. Antihypertensive use was independently associated with higher HbA1c (OR = 1.53, 95% CI: 1.30–1.80; p < 0.001), while NOAC use showed an inverse association (OR = 0.74, 95% CI: 0.55–0.99; p = 0.040). In multivariable analysis, atrial fibrillation was the only independent predictor of increased stroke severity, whereas HbA1c and other vascular risk factors were not significant. Stroke severity strongly predicted in-hospital mortality (OR = 1.27, 95% CI: 1.02–1.59; p = 0.032), prolonged hospitalization (OR = 1.31, 95% CI: 1.15–1.49; p < 0.001), and stroke-related death (OR = 2.18, 95% CI: 1.37–3.47; p = 0.002), while HbA1c was not associated with these outcomes. Discussion In conclusion, HbA1c was not associated with acute stroke severity. While it remains a valuable marker of long-term vascular risk, its role in predicting acute neurological injury appears limited. In contrast, established clinical tools—particularly the NIHSS—remain the most reliable instruments for early prognostic evaluation of stroke severity.