Prevalence of adults with brain arteriovenous malformations: a community based study in Scotland using capture-recapture analysis.

OBJECTIVE To conduct a population based study of brain arteriovenous malformation (AVM) prevalence. METHODS Multiple, overlapping sources of case ascertainment were used to establish the point prevalence of brain AVMs in the adult population of the Lothian health board of Scotland. Patients were sought retrospectively from all local general (family) practitioners, neurologists, neurosurgeons, stroke physicians, the specialist AVM clinic at the regional neuroscience centre, and routine coding of hospital discharge data. Case notes, brain imaging, and pathology reports were reviewed to validate each patient's diagnosis and to ensure that each was alive, over the age of 16 years, and resident in the geographical area of the study on the prevalence date of 30 June 1998. RESULTS Of 148 potentially eligible people, 93 adults met the inclusion criteria. There were 40 women and 53 men. Men were significantly younger than women on the prevalence date (median age 39 years v 51 years, p = 0.003). Of those included, 25 (27%) had radiological evidence of prior therapeutic obliteration of their brain AVM and 9 (10%) had coexisting aneurysms. The minimum crude brain AVM prevalence was 15 per 100 000 adults and capture-recapture analysis gave an ascertainment adjusted prevalence of 18 (95% confidence interval 16 to 24) per 100 000 adults. CONCLUSIONS The minimum estimate of brain AVM prevalence helps to assess its burden and comparative epidemiology and stresses the importance of brain AVMs as a cause of long term disability in adults.