Abstract 168: Assessing The Utility Of The Modified Rankin Scale (mRS) At Discharge To Predict Day 90 Outcomes In Acute Stroke Registries

Objective: The modified Rankin Scale (mRS) is a commonly used measure of functional stroke recovery, which is typically measured at 30 or 90 days post event. Given the difficulty of follow-up, most hospital-based stroke registries are usually limited to assessments at discharge. Studies have shown that mRS assessed 30 days post-stroke is a sufficient proxy for 90 day mRS, but little research has explored the utility of mRS assessment at discharge. The objective of this study was to assess the utility of mRS at discharge in predicting 90 day stroke outcomes. Methods: Data were obtained from a follow-up study of 373 acute stroke discharges from a statewide hospital-based acute stroke registry. Discharge mRS was obtained by chart review and 90 day outcomes data measured by the Barthel Index (BI) were obtained by phone. BI data were converted to 3 mRS levels: 0-2 (low to no), 3 (moderate), and 4-5 (severe) using validated methods. Weighted kappa was used to assess agreement between discharge and 90 day mRS. Logistic regression was used to assess the independent association between discharge mRS and disability at 90 days (defined as mRS 3-5 vs. 0-2). Results: Average age of the patients was 65 years, 56% were female, 28% were non-white, 74% had ischemic stroke, 14% had TIA, and 12% had hemorrhagic stroke. Distribution of mRS scores for 261 patients who completed the 90 day follow up is shown in Figure 1. The weighted kappa between discharge and 90 day mRS was 0.28 (95% CI 0.18, 0.38), indicating only fair agreement. After adjustment, those with moderate (3) or severe disability (4-5) at discharge were 2.49 (1.13, 5.54) and 2.55 (1.17-5.79) times more likely to have moderate to severe disability (3-5) at 90 days. (Table 1) Conclusion: Although discharge mRS was a strong independent predictor of disability at 90 days, the modest agreement between discharge and 90 day mRS indicate that it is not a sufficient proxy for 90 day outcomes. Further research is needed to identify predictors of stroke recovery based on assessments at hospital discharge.