Predictive value of functional disability scales among stroke survivors: A long-term mortality evaluation in a Brazilian stroke cohort

Objective: To assess the influence of two functional scales- Modified Rankin Scale (m -RS) and Modified Katz Index (m -Katz Index) on long-term mortality in a stroke cohort. Material and methods: Among 760 stroke survivors (median age: 66 (IQR:56-75), 56.4 % women) m -Katz Index and m -RS scales applied at 1 and 6 months after stroke, were investigated in relation to 12 -years of all -cause mortality. Kaplan-Meier survival curves were computed, and time -varying covariate Cox regression models were fitted to calculate hazard ratios (HRs) with 95 % confidence intervals (CIs) in all sample and by sex. The prognostic ability of the fitted models was computed for each model by six different measures. Results: After 12 years of follow-up (median survival time: 7.3 years), 311 participants died. Overall survival curves show lower survival rates among those with the highest levels of disability/dependence (all log -rank pvalues <0.0001). These findings were confirmed in all regression models for both sexes, particularly in men who had higher levels of dependence on Activities of Daily Living (ADLs) by m -Katz Index and severe disability by mRS and presented the highest HR of dying (HR: 3.34 (95 %CI: 2.27-4.92) and HR: 4.94 (95 % CI: 3.15-7.75), respectively). Conclusions: Both the m -Katz Index and the m -RS scale were good predictors of long-term mortality, which is of importance for guiding the functional rehabilitation of stroke patients. Besides, high levels of disability and dependence were implicated with high mortality risks, regardless of sex.