Association of prestroke glycemic status with stroke mortality

OBJECTIVE: The role of diabetes as a predictor of mortality after stroke remains uncertain, and there are very few data for pre-diabetes. This study investigated the association of pre-diabetes and diabetes with 30-day and 1-year mortality after ischemic stroke (IS) and primary intracerebral hemorrhage (ICH). RESEARCH DESIGN AND METHODS: Between 2006 and 2013, 2076 patients with IS and 586 patients with ICH (median age 79) were admitted to hospital within 24 hours after stroke onset and were treated in a stroke unit, where they underwent measurement of glycated hemoglobin (HbA1c). Diabetes was retrospectively defined based on medical history, diagnosis during hospital stay or HbA1c ≥6.5% (48 mmol/mol). Pre-diabetes was defined as HbA1c of 5.7%–6.4% (39–47 mmol/mol). Stroke severity was measured using the National Institutes of Health Stroke Scale (NIHSS). HRs were used to test the association of pre-diabetes and diabetes with 30-day and 1-year mortality after stroke onset. RESULTS: Among patients with IS, 830 had pre-diabetes and 632 had diabetes; 280 died within 30 days and the other 77 within 1 year. Among patients with ICH, 106 had pre-diabetes and 56 had diabetes; 150 died within 30 days and the other 92 within 1 year. In both stroke subtypes, pre-diabetes and diabetes were associated with higher 30-day mortality. In IS, however, the association was limited to patients with prestroke disability and very severe stroke. At NIHSS 25, HR was 1.58 (95% CI 1.07 to 2.35) for pre-diabetes and 1.67 (95% CI 1.14 to 2.46) for diabetes compared with normoglycemia. In ICH, the association was limited to women for pre-diabetes (HR 1.93, 95% CI 1.15 to 3.24) and to men for diabetes (HR 1.78, 95% CI 1.02 to 3.12). Prestroke glycemic status was unrelated to 1-year mortality. CONCLUSIONS: Both pre-diabetes and diabetes predict short-term mortality after acute stroke, but the association varies depending on both prestroke and stroke-related characteristics. These findings may explain the heterogeneous results obtained by previous studies.