Temporal trends in ischemic and hemorrhagic strokes in Northern Italy: results from the cardiovascular monitoring unit in Northern Italy population-based register, 1998-2004.

ABSTRACT

BACKGROUND: We compared rates and case fatality from a population-based stroke register in Northern Italy between 1998 and 2004 to assess changes over time and to evaluate changes in case diagnosis and management. METHODS: The WHO Multinational Monitoring of Trends and Determinants in Cardiovascular Disease criteria were used to identify suspected fatal or nonfatal events occurring among residents 35-74 years of age. Data on in-hospital treatments, symptoms and diagnostic tools were extracted. Out-of-hospital deaths were also investigated. The annual average relative change (ARC) in death rate, attack rate and case fatality were derived from Poisson models. RESULTS: Death rates due to ischemic stroke (IS) decreased [men ARC -12.7, 95% confidence interval (CI) -21.3 to -3.2; women ARC -14.0, 95% CI -23.3 to -3.5]. These reductions are attributable to decreases in case fatality; attack rates of nonfatal IS increased (men ARC 3.6, 95% CI 0.5-6.7; women ARC 4.1, 95% CI 0.0-8.2). IS patients showed a higher prevalence of dyslipidemia and hypertension and underwent MRI more frequently in 2004. Both findings may explain the increased proportions of less severe cases. Case fatality and attack rates for hemorrhagic strokes (HS) were stable, with an observed increased prevalence of patients under anticoagulant/antiplatelet treatments. CONCLUSIONS: In this low-IS-incidence population, death rates decreased substantially during the investigated period. More accurate diagnostic tools increase the probability of detecting less severe cases. HS remains a frequently fatal disease with a stable incidence.