Trends in the incidence and mortality of intracerebral hemorrhage, and the associated risk factors, in Denmark from 2004 to 2017

Background and purpose The distribution of the major modifiable risk factors for intracerebral hemorrhage (ICH) changes rapidly. These changes call for contemporary data from large-scale population-based studies. The aim of the present study was to examine trends in incidence, risk factors, and mortality in ICH patients from 2004 to 2017. Methods In a population-based cohort study, we calculated age- and sex-standardized incidence rates (SIRs), incidence rates (IRs) stratified by age and sex per 100,000 person-years, and trends in risk profiles. We estimated absolute mortality risk, and the Cox proportional hazards regression multivariable-adjusted hazard ratios for 30-day and 1-year mortality. Results We included 16,902 patients (53% men; median age 75 years) from 2004 to 2017. The SIR of ICH decreased from 33 (95% confidence interval [CI] 32-34) in 2004/2005 to 28 (95% CI 27-29) in 2016/2017. Among patients aged >= 70 years, the IR decreased from 137 (95% CI 130-144) in 2004/2005 to 112 (95% CI 106-117) in 2016/2017. The IR in patients aged <70 years was unchanged. From 2004 to 2017, the proportion of patients with hypertension increased from 49% to 66%, the use of oral anticoagulants increased from 7% to 18%, and the use of platelet inhibitors decreased from 40% to 28%. The adjusted hazard ratio for 30-day mortality in 2016/2017 was 0.94 (95% CI 0.89-1.01) and 1-year mortality was 0.98 (95% CI 0.93-1.04) compared with 2004/2005. Conclusion The incidence of spontaneous ICH decreased from 2004 to 2017, with no clear trend in mortality. The risk profile of ICH patients changed substantially, with increasing proportions of hypertension and anticoagulant treatment. Given the high mortality rate of ICH, further advances in prevention and treatment are urgently needed.