Nation-wide Japanese FTD consortium FTLD-J: Utility of case review meetings

Objectives: To clarify the characteristics of Japanese patients with frontotemporal dementia (FTD), we have established a nationwide multicenter registry named the Frontiers of Time course and Living specimen registry and Disease-modifying therapy development in Japanese patients with FTLD (FTLD-J). To ensure diagnostic consistency, we implemented case review meetings in the registry and evaluated their utility. Methods: Between February 2016 and August 2024, 269 patients with behavioral variant FTD (bvFTD), semantic dementia (SD), or progressive nonfluent aphasia (PNFA) were registered. Fifteen case review meetings, open to all participating facilities, were held, where the clinical course, neuropsychiatric-neuropsychological evaluations, and neuroimaging analysis of 238 out of 269 cases were presented. Initial diagnoses were approved or revised based on discussions among specialists regarding whether the cases met the diagnostic criteria. We examined the diagnostic stability in participants initially diagnosed with bvFTD, SD, and PNFA. Given the limited number of PNFA cases, we compared the rate of diagnostic changes between bvFTD and SD using the chi-square test. Results: Of the 126 participants enrolled as bvFTD, 75 were confirmed as bvFTD. In the remaining 51 patients, the diagnoses changed during the meeting. Of the 95 participants enrolled as SD, 77 were confirmed as SD, and in 18 cases, the diagnoses changed. Of the 17 participants enrolled as PNFA, 15 were confirmed as PNFA; bvFTD had a predominantly higher rate of diagnostic change than those with SD (p < 0.001). Conclusions: Our results suggested that case review meetings in a multicenter study may improve diagnostic consistency, especially in bvFTD.