Impact of teaching intensity and academic status on medical resource utilization by teaching hospitals in Japan

Teaching hospitals require excess medical resources to maintain high-quality care and medical education. To evaluate the appropriateness of such surplus costs, we examined the impact of teaching intensity defined as activities for postgraduate training, and academic status as functions of medical research and undergraduate teaching on medical resource utilization. Administrative data for 47,397 discharges from 40 academic and 12 non-academic teaching hospitals in Japan were collected. Hospitals were classified into three groups according to intern/resident-to-bed (IRB) ratio. Resource utilization of medical services was estimated using fee-for-service charge schedules and normalized with case mix grouping. 15-24% more resource utilization for laboratory examinations, radiological imaging, and medications were observed in hospitals with higher IRB ratios. With multivariate adjustment for case mix and academic status, higher IRB ratios were associated with 10-15% more use of radiological imaging, injections, and medications; up to 5% shorter hospital stays; and not with total resource utilization. Conversely, academic status was associated with 21-33% more laboratory examinations, radiological imaging, and medications; 13% longer hospital stays; and 10% more total resource utilization. While differences in medical resource utilization by teaching intensity may not be associated with indirect educational costs, those by academic status may be. Therefore, academic hospitals may need efficiency improvement and financial compensation.