Incidence of cerebral cavernous malformations among adults in Scotland: a prospective, population-based study

BACKGROUND: Information about the incidence of cerebral cavernous malformations (CCM) is sparse and the effect of increasing MRI availability is uncertain. Our objective was to assess the incidence of symptomatic and incidental CCM over time. METHODS: This prospective, population-based study used multiple overlapping sources of case ascertainment to identify all adults aged ≥16 years who were newly diagnosed with CCM using brain MRI or pathology in Scotland between 1 January 1999 and 31 December 2003 or 1 January 2006 and 31 December 2010 inclusive. Crude, age-stratified, sex-stratified and symptomatic versus incidental CCM incidence rates were calculated using Scottish mid-year population estimates. RESULTS: The crude incidence for 300 newly diagnosed CCM cases (median age 44 years, 141 (47%) men) was 0.72 (95% CI 0.64 to 0.80) per 100 000 adults per year, with similar rates for men and women. The incidence of symptomatic CCM was higher than that of incidentally detected CCM (0.40 (0.34 to 0.47) versus 0.31 (0.26 to 0.37), p=0.028). Between 1999-2003 and 2006-2010, there were statistically non-significant increases in symptomatic and incidental incidence of CCM (0.36 (0.28 to 0.45) to 0.44 (0.36 to 0.54), p=0.18; 0.30 (0.23 to 0.38) to 0.33 (0.26 to 0.41), p=0.59). The estimated probability of becoming symptomatic for people with asymptomatic CCM was 0.25% (0.22%-0.29%) per year. Overall incidence increased with age, adjusted for year of diagnosis and sex (adjusted incidence rate ratio 1.09 (1.01 to 1.17) per decade increase, p=0.019). CONCLUSIONS: The incidence of symptomatic CCM exceeded that of incidentally discovered CCM; however, no significant change was observed over time. Approximately 1 in 400 people with asymptomatic CCM become symptomatic annually. These findings can help plan healthcare service delivery and research study recruitment.