Research on the Current Status of Pharmacists’ Professional Functions in Hospitals and Factors Influencing Their Improvement and Expansion

Background The healthcare system of Japan faces mounting challenges, including population aging, medical complexity, and workforce shortages. Hospital pharmacists are expected to ensure the safe and effective use of medicines and contribute to multidisciplinary care; however, their availability and functions remain uneven. The “Ward Pharmaceutical Care Fee I” (WardPharm-1) serves as an indicator of the implementation of advanced ward-based pharmaceutical care. This study investigated the national trends and determinants of WardPharm-1 filing, focusing on pharmacist-to-bed ratios and hospital characteristics, to identify factors enabling high-quality pharmacist services. Methods We examined national open datasets from the Ministry of Health, Labor, and Welfare for fiscal years 2021–2023, linking the “List of Registered Medical Care Providers (Medical)” and the “Hospital Bed Function Report.” Hospitals eligible for WardPharm-1 filing were identified, excluding psychiatric facilities and those not fulfilling minimum staffing standards. Per-100-bed staffing for eight healthcare professions and hospital bed counts were determined. Logistic regression and receiver operating characteristic (ROC) curve analyses determine the association between pharmacist staffing (Ph/100 beds) and WardPharm-1 filing, stratified by hospital type, Diagnosis Procedure Combination (DPC) group, and regional population density. Results Among ~5800 eligible hospitals annually, 31%–34% filed WardPharm-1. Pharmacist staffing per 100 beds demonstrated the strongest association with filing (odds ratio ≈1.2 annually), exceeding that in all other professions. Median Ph/100 beds were ~5.2 in filing hospitals and 2.6 in non-filers, with cutoff values of 3.7–4.0 pharmacists/100 beds (area under the ROC curve 0.83–0.84). WardPharm-1 filing was most frequent in general hospitals (≈50%) and DPC university or specified-function hospitals (≈90%) and least frequent in long-term care hospitals (≈3%) and depopulated regions (<25%). Sustained filers maintained Ph/100 beds around 5.2, whereas withdrawal correlated with declines to 3.4–4.3. Filing hospitals generally had twice the bed counts of non-filers. Conclusions WardPharm-1 filing strongly depends on the pharmacist-to-bed ratio. Higher-function hospitals require higher staffing density, whereas smaller or rural hospitals exhibit lower filing rates, suggesting workforce maldistribution. Strengthening ward-based pharmacist services will necessitate addressing staffing imbalances and advancing digital transformation, task shifting, and interprofessional collaboration to ensure administration of safe, efficient pharmacotherapy across Japan.