Diabetes duration, glycemic control, and risk of stroke and stroke subtypes: a nationwide prospective cohort study

To evaluate the relationship of diabetes duration and glycemic control with risk of stroke and its major subtypes using data from the UK Biobank, a large population-based cohort of UK adults. We included 23,401 UK adult residents with diabetes who had no known stroke at baseline (2006-2010). Diabetes duration was self-reported and glycemic control was assessed by glycated hemoglobin (HbA1c) levels. Their associations with incident stroke were assessed using multivariate Cox models. During a median follow-up of 11.6 years, 982 incident cases of stroke were identified. A longer diabetes duration was associated with higher risk of total stroke, ischemic stroke (IS), and hemorrhagic stroke (HS) (≥ 15 vs. <5 years: HRs [95% CI] were 1.81 [1.50, 2.19], 1.80 [1.47, 2.20], and 2.17 [1.46, 3.23], respectively), while higher levels of HbA1c were associated with higher risk of total stroke and IS but not HS (≥ 8.0% vs. <7.0%: HRs [95% CI] were 1.78 [1.52, 2.09], 1.93 [1.63, 2.28], and 0.97 [0.67, 1.41], respectively). Diabetes duration interacted with glycemic status on total stroke and IS (both P-for-interaction values < 0.01). Individuals who had the longest diabetes duration (≥ 15 years) and poorer glycemic control (≥ 8.0%) had particularly higher risk of total stroke (HR = 3.21; 95% CI: 2.55, 4.04) and IS (HR = 3.47; 95% CI: 2.73, 4.40) as compared with those who had a duration of < 5 years with HbA1c < 8%. A longer diabetes duration and poorer glycemic control were both associated with higher risk of total stroke and IS, and the risk may be further exacerbated with the coexistence of both risk factors.