Staffing level in the discharge planning department and average length of stay in acute care wards: A cross-sectional study using a nationwide hospital- and ward-level data in Japan

Background The transition from hospital to the next care setting is when care fragmentations are likely to occur, making discharge planning essential; however, the relationship between discharge planning and length of stay is unclear. This study aimed to investigate the association between staffing levels, particularly the number of nurses and medical social workers in the discharge planning department, and the average length of stay at the ward level in acute care hospitals in Japan. Methods Applying a cross-sectional approach, we used nationwide administrative hospital- and ward-level data from the fiscal year 2021. A total of 5,580 acute care wards in 1,101 hospitals across 206 secondary medical areas were included. A two-level multilevel regression analysis with random intercept stratified by three types of acute care ward functions was performed by adjusting ward, hospital, and regional characteristics. Results A total of 1,017 wards in 70 designated special function hospitals, 3,828 general acute care wards with a 7:1 patient-to-nurse ratio in 596 hospitals, and 735 general acute care wards with a 10:1 patient-to-nurse ratio in 435 hospitals were included in the final analysis. The average length of stay was 12.5 days, 11.5 days, and 18.0 days, respectively. There was a significant association between the total number of nurses and medical social workers per 100 hospital beds in acute care wards with a 7:1 patient-to-nurse ratio, but not in special function wards or in acute care wards with a 10:1 patient-to-nurse ratio. Sensitivity analysis that separately analysed the number of nurses and medical social workers showed that the number of nurses per 100 hospital beds was associated with the average length of stay in acute care wards with a 7:1 patient-to-nurse ratio. Medical social workers per 100 hospital beds showed no association in any ward model. Conclusions A greater number of nurses and medical social workers per 100 hospital beds in the discharge planning department, especially greater nurse staffing, was associated with short lengths of stay in acute care wards with a 7:1 patient-to-nurse ratio.