Temporal Trends in Incidence and Case Fatality of Intracerebral Hemorrhage: The Tromsø Study 1995-2012

Abstract

Background: The aim of this study was to explore temporal trends in incidence and case fatality rates of intracerebral hemorrhage (ICH) over the last two decades in a Norwegian municipality. Methods: Incident cases of primary ICH were registered in the period from 1995 through 2012 in 32,530 participants of the longitudinal population-based Tromsø Study. Poisson regression models were used to obtain incidence rates over time in age- and sex-adjusted and age- and sex-specific models. Case fatality rates were calculated and age- and sex-adjusted trends over time were estimated using logistic regression. Results: A total of 226 ICHs were registered. The age- and sex-adjusted incidence rate [95% confidence interval (CI)] in the overall population was 0.42 (0.37-0.48) per 1,000 person-years. Age-adjusted incidence rates were 0.53 (0.43-0.62) in men and 0.33 (0.26-0.39) in women. In individuals aged <75 years, the age- and sex-adjusted incidence rate was 0.27 (0.22-0.32) and in individuals aged ≥75 years, it was 2.42 (1.95-2.89) per 1,000 person-years. There was no significant change in incidence rates over time. The incidence rate ratio (95% CI) in the overall population was 0.73 (0.47-1.12) in 2012 compared with 1995. The overall 30-day case fatality (95% CI) was 23.9% (18.3-29.5) and did not change substantially over time [odds ratio in 2012 vs. 1995 = 0.83 (95% CI 0.27-2.52)]. Conclusion: No significant changes in incidence and case fatality rates of ICH were observed during the last two decades.