Changes in stroke incidence, outcome, and associated factors in Porto between 1998 and 2011

Objective Year 2000 marked a turning point in stroke prevention and treatment in Portugal. In face of high incidence rates stroke awareness campaigns, close surveillance of vascular risk factors and implementation of hospital stroke units were advanced by the National Health Authorities. To understand the effect of such measures, we assessed changes in stroke incidence and short-term outcome using data from two community-based registers undertaken in Porto in 1998-2000 and 2009-2011. Methods We used standard diagnostic criteria and multiple overlapping sources of case-ascertainment for first-ever strokes. Short-term outcome was measured by the modified Rankin Scale; disabling stroke was defined whenever post-stroke mRS score>pre-stroke mRS and >1. Results Globally, 462 and 405 first-ever stroke cases were registered in 1998-2000 and 2009-2011, respectively. Stroke incidence decreased by 23%, from 261 to 203/100,000 after adjustment for the Portuguese population. Significant reduction was found in those aged <75 years (31%) and in women (32%). Incidence of disabling strokes was reduced by 29%. Fatal strokes decreased by 46%, while intracerebral hemorrhage decreased by 51%. Risk of disability from stroke decreased by 11% (RR = 0.89; 95%CI, 0.81-0.98) in 2009-2011, as found after adjusting for patient/stroke characteristics in a Poisson model. Moreover, when patients arrived hospital within 3 h from stroke onset, the risk of disabling stroke was 0.76 (95%CI, 0.67-0.87) in 2009-2011 vs. 1998-2000, compared to 1.03 (95%CI, 0.89-1.12) for late arrival. Conclusion Risk of stroke, mainly of hemorrhagic stroke, was substantially reduced over time. Timely action in acute phase was responsible for the decline in disability across periods.