Objective: To assess the correlation between lifelong learning for physical therapists and regional differences in the provision of rehabilitation services. Materials and Methods: We conducted an ecological study using open data from the 2019 National Database of Health Insurance Claims and Specific Health Checkups. We investigated claims for disease-specific rehabilitation. The standardized claims ratio (SCR) for each of the 47 prefectures was calculated to evaluate regional differences. We also examined the number of certified physical therapists (CPTs) and specialist physical therapists (SPTs) in each prefecture certified by the Japan Physical Therapy Association across specialty fields. Population-adjusted therapist density was expressed per 100,000. Prefecture-level correlations between the SCR for each disease-specific rehabilitation program and therapist density were evaluated using Spearman's rank correlation. Multiple tests were performed using Storey's q-value method. Results: The SCRs for disease-specific rehabilitation showed regional variation. The SCR for respiratory rehabilitation had the largest range (32.2-192.5). The population-adjusted numbers of CPTs and SPTs ranged from 3.9-14.7 and 0.4-6.9 per 100,000 population, respectively. The SCR for cardiovascular rehabilitation was positively correlated with the CPT field, "orthopedic disorders" (ρ=0.54, q<0.01) and the SPT field, "orthopedic physical therapy" (ρ=0.45, q<0.05). The cerebrovascular rehabilitation SCR was positively correlated with the CPT field, "prevention for frail elderly" (ρ=0.45, q<0.05). Conclusion: Japanese prefectures with greater densities of CPTs or SPTs delivered higher volumes of rehabilitation services. Our findings suggest that the unequal distribution of postgraduate educational opportunities and certified personnel may contribute to these regional differences. Strengthening access to lifelong learning and specialty certifications in underserved regions may help reduce geographic disparities in rehabilitation services.
