Nationwide survey on cerebral amyloid angiopathy in Japan.

Background and purpose A nationwide survey was conducted to understand the epidemiology of cerebral amyloid angiopathy-related intracerebral hemorrhage (CAA-related ICH) and cerebral amyloid angiopathy-related inflammation/vasculitis (CAA-ri) in Japan. Methods To estimate the total number and clinical features of patients with CAA-related ICH and CAA-ri between January 2012 and December 2014 and to analyze their clinical features, questionnaires were sent to randomly selected hospitals in Japan. Results In the first survey, 2348 of 4657 departments responded to the questionnaire (response rate 50.4%). The total numbers of reported patients with CAA-related ICH and CAA-ri were 1338 and 61, respectively, and their total numbers in Japan were estimated to be 5900 [95% confidence interval (CI) 4800-7100] and 170 (95% CI 110-220), respectively. The crude prevalence rates were 4.64 and 0.13 per 100 000 population, respectively. The clinical information of 474 patients with CAA-related ICH obtained in the second survey was as follows: (i) the average age of onset was 78.4 years; (ii) the prevalence increased with age; (iii) the disease was common in women; and (iv) hematoma most frequently occurred in the frontal lobe. Sixteen patients with CAA-ri for whom data were collected in the second survey had the following characteristics: (i) median age of onset was 75 years; (ii) cognitive impairment and headache were the most frequent initial manifestations; and (iii) focal neurological signs, such as motor paresis and visual disturbance, were frequently observed during the clinical course. Conclusions The numbers of patients with CAA-related ICH and CAA-ri in Japan were estimated.