Cerebrovascular risk factors and their time-dependent effects on stroke survival in the EMMA cohort study

ABSTRACT

To investigate the time-dependent effects of traditional risk factors on functional disability in all-cause mortality post-stroke, we evaluated data from a long-term stroke cohort. Baseline cerebrovascular risk factors (CVRF) and functionality at 1 and 6 months were evaluated in survivors from a prospective stroke cohort using the modified Rankin scale (m-RS), which classifies participants as improvement of disability, unchanged disability (at least moderate), and worsening disability. Cox regression models considering baseline risk factors, medication use, and functionality 6 months after stroke were fitted to identify their time-dependent effects up to 12 years of follow-up. Adjusted hazard ratios (HR) with 95% confidence intervals (CI) are presented. Among 632 survivors (median age 68, 54% male, 71% first-ever episode), age and functional disability (unchanged and worsening) 6 months after ischemic stroke had time-dependent effects on all-cause mortality risk up to 12 years of follow-up. The most impacting risk factors were unchanged (at least moderate) (HR, 2.99; 95%CI 1.98-4.52) and worsening disability (HR, 2.85; 95%CI 1.26-6.44), particularly in the first two years after a stroke event (Time 1 ≥6 mo to <2.5 y). Worsening disability also impacted mortality in the period from ≥2.5 to <7.5 years (Time 2) of follow-up (HR, 2.43 (95%CI 1.03-5.73). Other baseline factors had a fixed high-risk effect on mortality during follow-up. Post-stroke and continuous medication use had a fixed protective effect on mortality. Functional disability was the main contributor with differential risks of mortality up to 12 years of follow-up.