Insulin Resistance and Prognosis of Nondiabetic Patients With Ischemic Stroke: The ACROSS-China Study (Abnormal Glucose Regulation in Patients With Acute Stroke Across China).

BACKGROUND AND PURPOSE Insulin resistance was common in patients with stroke. This study investigated the association between insulin resistance and outcomes in nondiabetic patients with first-ever acute ischemic stroke. METHODS Patients with ischemic stroke without history of diabetes mellitus in the ACROSS-China registry (Abnormal Glucose Regulation in Patients With Acute Stroke Across China) were included. Insulin resistance was defined as a homeostatis model assessment-insulin resistance (HOMA-IR) index in the top quartile (Q4). HOMA-IR was calculated as fasting insulin (μU/mL)×fasting glucose (mmol/L)/22.5. Multivariable logistic regression or Cox regression was performed to estimate the association between HOMA-IR and 1-year prognosis (mortality, stroke recurrence, poor functional outcome [modified Rankin scale score 3-6], and dependence [modified Rankin scale score 3-5]). RESULTS Among the 1245 patients with acute ischemic stroke enrolled in this study, the median HOMA-IR was 1.9 (interquartile range, 1.1-3.1). Patients with insulin resistance were associated with a higher mortality risk than those without (adjusted hazard ratio, 1.68; 95% confidence interval, 1.12-2.53; P=0.01), stroke recurrence (adjusted hazard ratio, 1.57, 95% confidence interval, 1.12-2.19; P=0.008), and poor outcome (adjusted odds ratio, 1.42; 95% confidence interval, 1.03-1.95; P=0.03) but not dependence after adjustment for potential confounders. Higher HOMA-IR quartile categories were associated with a higher risk of 1-year death, stroke recurrence, and poor outcome (P for trend =0.005, 0.005, and 0.001, respectively). CONCLUSIONS Insulin resistance was associated with an increased risk of death, stroke recurrence, and poor outcome but not dependence in nondiabetic patients with acute ischemic stroke.