Trends in the incidence of newly diagnosed cerebral cavernous malformations in Finland: a population-based retrospective cohort study

Background: The few previous studies that have estimated the incidence of cerebral cavernous malformations (cavernomas) have reported incidence rates of 0.2–1.9/100,000 for diagnosed cavernomas. Our aim was to describe incidence trends of cavernomas by clinical presentation. Methods: We conducted a retrospective cohort study of cavernomas diagnosed at two university hospitals in Finland (Kuopio University Hospital, KUH and Tampere University Hospital, TAUH). Cavernoma diagnoses during 2004–2020 were identified from the KUH and TAUH Care registry databases and verified from medical records and diagnostic imaging studies. We calculated the age-standardized incidence rates using the European standard population and analysed incidence trend and changes in trend by sex, age group, and calendar year using Poisson regression. Findings: A total of 669 cavernoma diagnoses were identified during 2004–2020 in the combined KUH and TAUH population. The age-standardized incidence rate was 2.01/100,000 (95% confidence interval (CI) 1.85–2.16) for all cavernoma diagnoses, 1.25/100,000 (1.13–1.37) for asymptomatic, 0.75/100,000 (0.66–0.85) for symptomatic, and 0.46/100,000 (0.39–0.53) for ruptured cavernomas. No significant difference in the incidence of cavernoma diagnoses was seen between the KUH and TAUH populations or between the sexes. Incidence of cavernomas was highest at ages 40–59 years and low in those under 20 or over 80 years of age. Incidence of diagnosed cavernomas, especially asymptomatic, increased during the study period. Interpretation: In our population-based study, incidence of cavernomas was higher than previously reported and increased during the study period. The burden imposed by cavernomas on healthcare system is considerable and increasing. Funding: The Research Council of Finland, Kuopio University Hospital, Tampere University Hospital, and Wellbeing services county of Pirkanmaa.