Impact of Oral Nutritional Supplementation at Hospital Discharge on Healthcare Costs in Older Adults: A Retrospective Analysis of Japanese Claims Data

Aim: Malnutrition is a common and costly challenge among hospitalized patients and those requiring postdischarge care. Oral nutritional supplements (ONSs) are a low-cost intervention for undernourished individuals. This study used the Kokuho Database (KDB) to examine the health economic impact of prescribing ONSs at discharge for hospitalized older adults. Methods: This retrospective study included patients aged 75 years and older who were discharged from hospitals in Saitama Prefecture, as recorded in the KDB, from April 2017 to March 2022. Patients prescribed ONSs at discharge were classified as the ONS-at-discharge (ONSd) group, and those not prescribed were classified as the no-ONS-at-discharge (non-ONSd) group. Healthcare costs over 360 days postdischarge were compared using propensity score matching. Results: A total of 526 605 patients were enrolled: 13 042 in the ONSd group and 513 563 in the non-ONSd group. After matching, 26 084 patients (13 042 per group) were included in the analysis. Over 360 days, healthcare costs were higher in the ONSd group than in the non-ONSd group (935 092 yen vs. 860 588 yen, adjusted p < 0.001). Among patients not prescribed ONS during follow-up, 360-day costs remained higher in the ONSd group (882 465 yen vs. 847 700 yen, adjusted p < 0.001). Conversely, among patients prescribed ONS during follow-up, 360-day costs were lower in the ONSd group (1 040 830 yen vs. 1 185 919 yen, adjusted p < 0.001). Conclusion: Healthcare costs over 360 days were higher in the ONSd group compared with the non-ONSd group. However, among patients who continued ONS use after discharge, costs were lower in the ONSd group.