Persistently uneven deep brain stimulation management in Japan: a nationwide claims analysis, 2014-2024

Background: The long-term benefit of deep brain stimulation (DBS) for neurological disorders depends on sustained post-implantation management, yet its geographic distribution remains poorly characterised. We aimed to describe regional variation, persistence, and longitudinal change in DBS management activity across Japan. Methods: We used claims from the National Database of Health Insurance Claims (NDB) Open Data during 2014-2024. Annual billings for DBS management were expressed per million population. Annual between-prefecture unevenness was summarised by the Gini coefficient of the prefecture DBS management billing rate. We evaluated longitudinal trajectories and trends in DBS management billing rates relative to the national rate, and related baseline billing rates to subsequent trends. Findings: From 2014 to 2024, national DBS management billings increased from 18,659 to 27,233, totalling 258,408. Between-prefecture unevenness remained high throughout (Gini coefficient, 0.54 to 0.40), and its narrowing decelerated over the study period. In 2024, the prefecture at the 90th percentile still billed at 9.1 times the rate of the prefecture at the 10th. Of the 23 low-baseline prefectures, nine showed a subsequent decline in relative billing rate; nonetheless, lower baseline DBS management billing rates were associated with a more positive relative rate of change overall. Interpretation: Ongoing post-implantation DBS management activity was markedly uneven and persistent across Japan. The observations suggest that universal health coverage and national-level growth do not by themselves ensure equitable long-term DBS treatment. This nationwide, longitudinal description could inform policies aimed at reducing geographic barriers to long-term specialist care across healthcare systems. Funding: None.