Long-Term Post-Stroke Functional Outcomes: A Comparison of Diabetics and Nondiabetics

INTRODUCTION: Diabetes mellitus (DM) is known to influence outcomes in the short term following stroke. However, the impact of DM on long-term functional outcomes after stroke is unclear. We compared functional outcomes periodically over 7 years between diabetic and nondiabetic ischemic stroke patients, and investigated the impact of DM on the long-term trajectory of post-stroke functional outcomes. We also studied the influence of age on the diabetes-functional outcome association. METHODS: This is a longitudinal observational cohort study of 802 acute ischemic stroke patients admitted to the Singapore General Hospital 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 were determined at 6 months and at median follow-up durations of 29 and 86 months. RESULTS: Among the 802 ischemic stroke patients studied (mean age 64 ± 12 years, male 63%), 42% had DM. In regression analyses adjusting for covariates, diabetic patients were more likely to have poor functional outcomes at 6 months (OR = 2.12, 95% CI: 1.23–3.67) and at median follow-up durations of 29 months (OR = 1.96, 95% CI: 1.37–2.81) and 86 months (OR = 2.27, 95% CI: 1.58–3.25). In addition, age modulated the effect of DM, with younger stroke patients (≤65 years) more likely to have long-term poor functional outcome at the 29-month (p = 0.0179) and 86-month (p = 0.0144) time points. CONCLUSIONS: DM was associated with poor functional outcomes following ischemic stroke in the long term, with the effect remaining consistent throughout the 7-year follow-up period. Age modified the effect of DM in the long term, with an observed increase in risk in the ≤65 age-group but not in the >65 age-group.