Background: Stroke and diabetes are important causes of disability. The impact of diabetes on long-term functional outcomes after stroke is unclear. Our primary aim was to compare functional outcomes periodically over 7 years between diabetic and non-diabetic ischemic stroke patients. We also investigated the impact of diabetes on the long-term trajectory of functional outcomes, and the influence of age on the diabetes-functional outcome association.
Methods: This is a longitudinal observational cohort study of 802 acute ischemic stroke patients recruited from a tertiary hospital in Singapore from 2005 to 2007. Functional outcomes were assessed using the modified Rankin Scale (mRS) with poor functional outcome defined as mRS ≥ 3. Follow-up data was determined at 6 months, a median of 29 months and 86 months.
Results: Among the 802 ischemic stroke patients studied, 45% were > 65 years old and 42% had diabetes. Diabetic patients were more likely to have poor functional outcomes at 6 months (OR = 2.122, 95% CI: 1.226-3.673), and at median follow-up durations of 29 months (OR = 1.957, 95% CI: 1.366-2.814) and 86 months (OR = 2.269, 95% CI: 1.583-3.253), after adjustment of covariates. Diabetes was not an interaction factor for both mRS distribution and poor functional outcome when comparing between the various follow-up time-points. There was a significant interaction between age and diabetic status in terms of poor functional outcome in the long-term.
Conclusion: Diabetes is a prognostic factor for poor functional outcomes after ischemic stroke; its impact remained consistent throughout the 7-year follow-up period and was influenced by age in the long-term.