Initiation and Development of Nurse Practitioner Practice in a Japanese Rehabilitation Hospital: A Mixed-Methods Descriptive Study.

Introduction Nurse practitioners (NPs) in Japan are primarily concentrated in acute care settings, with limited integration into rehabilitation hospitals. As Japan's healthcare system increasingly emphasizes chronic and community-based care, understanding NP roles in post-acute rehabilitation is essential. This study aimed to examine the initiation and development of NP practice in a Japanese rehabilitation hospital, focusing on the scope, processes, and patterns of clinical activities. Methods We conducted a mixed-methods descriptive study at Kanagawa Rehabilitation Hospital over 12 months (April 2023-March 2024). All NP-involved clinical activities were extracted from hospital records, including the date, care setting, department, initiation mode, and free-text intervention descriptions. Quantitative data were analyzed using descriptive statistics, while qualitative content analysis identified thematic domains of NP practice. Results A total of 738 NP activities were recorded, most occurring in adult inpatient wards (n = 623, 84.4%), followed by pediatrics (n = 87, 11.8%) and clerical/administrative contexts (n = 28, 3.8%). Activities were concentrated in internal medicine (30.5%) and orthopedic (29.7%) departments. Over half of all interventions were self-initiated (415, 56.2%), indicating substantial professional autonomy. Qualitative analysis revealed four primary domains: direct clinical management (e.g., medication adjustments, swallowing care), care coordination (e.g., multidisciplinary conferences, interdepartmental referrals), patient and family education (e.g., disease-specific counseling, self-management guidance), and administrative/quality improvement activities (e.g., order entry, safety initiatives). Conclusion This study indicates that NP practice in rehabilitation settings encompasses diverse clinical, coordination, educational, and administrative roles, reflecting a high level of professional autonomy and integration into multidisciplinary care. These results provide insight into the scope and characteristics of NP practice in post-acute rehabilitation settings in Japan. Future studies are needed to evaluate the impact of NP integration on measurable patient and system-level outcomes, including quality, efficiency, and continuity of care.