Temporal trends in incidence and case fatality of intracerebral hemorrhage: The Tromsø Study 1995-2012

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.