Risk of mortality and recurrence after first-time stroke among patients with type 2 diabetes: A Danish nationwide cohort study.

Introduction: The prognosis for stroke patients with type 2 diabetes mellitus (T2DM) remains poorly understood. We examined the risk of mortality and stroke recurrence in stroke patients with T2DM and stroke patients without diabetes.

Patients and methods: We conducted a population-based cohort study including all patients diagnosed with a first-time ischemic stroke (n = 131,594) or intracerebral hemorrhage (ICH, n = 15,492) in Denmark, 2005-2021. Patients with T2DM were identified using hospital diagnosis codes and glucose-lowering drug prescriptions. We calculated risks, risk differences, and risk ratios, standardized by age, sex, and calendar year of stroke admission.

Results: Following ischemic stroke, the 5-year standardized mortality was 46.1% for patients with T2DM and 35.4% for patients without diabetes (standardized risk difference: 10.7% [95% CI 9.9-11.6]; risk ratio: 1.3 [95% CI 1.3-1.3]). The 5-year risk of recurrence following ischemic stroke was 12.7% for patients with T2DM and 11.3% for those without diabetes (risk difference: 1.4% [95% CI 0.9-2.0]; risk ratio: 1.1 [95% CI 1.1-1.2]). Following ICH, the 5-year mortality was 62.8% for patients with T2DM and 53.0% for patients without diabetes (risk difference: 9.8% [95% CI 7.2-12.4)]; risk ratio: 1.2 [95% CI 1.1-1.2]). The 5-year risk of recurrence after ICH was 9.1% for patients with T2DM and 9.7% for patients without diabetes.

Discussion and conclusion: Stroke patients with T2DM were at increased risk of mortality. The risk of stroke recurrence was slightly higher for ischemic stroke patients with T2DM than patients without diabetes, while no difference was observed among ICH patients.