Association of high psychiatrist staffing with prolonged hospitalization, follow-up visits, and readmission in acute psychiatric units: a retrospective cohort study using a nationwide claims database

Abstract

Background

The effects of psychiatrist staffing are unclear. The aim of this study was to assess the association of high psychiatrist staffing with prolonged hospitalization, follow-up visits, and readmission in acute psychiatric units.

Methods

A retrospective cohort study was conducted using the National Database of Health Insurance Claim Information and Specified Medical Checkups. Patients newly admitted to acute psychiatric units between October 2014 and September 2015 were followed up until September 2016. The primary exposure was a patient-to-psychiatrist ratio of 16:1 (high-staffing units) vs 48:1 (low-staffing units). Outcomes were prolonged hospitalization of >90 days, number of follow-up psychiatric visits within 90 days after discharge, and psychiatric readmission within 90 days after discharge. Incidence rate ratios (IRRs) and their 95% confidence intervals (CIs) were estimated by using generalized estimating equations, adjusting for potential covariates.

Results

Among the 24,678 newly admitted patients at 190 hospitals, 13,138 patients (53.2%) were admitted to high-staffing units in 92 hospitals. After adjustment, high-staffing units were associated with a lower risk of prolonged hospitalization (incidence rate, 16.9 vs 21.3%; IRR, 0.79 [95% CI, 0.70, 0.89]), higher number of follow-up visits (incidence rate of ≥7 visits, 16.9 vs 13.4%; IRR, 1.06 [95% CI, 1.01, 1.12]), and lower risk of readmission (incidence rate, 13.0 vs 14.4%; IRR, 0.90 [95% CI, 0.82, 0.99]).

Conclusion

High-staffing units are associated with a reduced risk of prolonged hospitalization and readmission and an increased number of follow-up visits. Further research is needed to improve the generalizability of these findings and establish the optimal level of staffing.

Keywords:

• readmission rate
• length of stay
• quality of care
• physician ratio
• workforce
• psychiatrist staffing

Supplementary material

Table S1 Full estimates from multivariable models for psychiatrist staffing and outcomes

Acknowledgments

We would like to thank Editage for English language editing. This work was funded by a Research on Policy Planning and Evaluation grant from the Ministry of Health, Labour and Welfare of Japan.

Disclosure

During the past 3 years, YO received personal fees from Merck & Co., Inc., Janssen Pharmaceuticals, Inc., Medical Technology Association, Cando Inc., and Japan Medical Data Center. He has also received research grants from the Japan Agency for Medical Research and Development, the Ministry of Health, Labour and Welfare, the Japan Society for the Promotion of Science, the Institute for Health Economics and Policy, and the Mental Health and Morita Therapy. NaS reports grants from the Ministry of Health, Labour and Welfare, personal fees and nonfinancial support from Otsuka Pharmaceutical, Janssen Pharmaceutical KK, Eli Lilly Japan KK, Pfizer Inc., Meiji Seika Pharma Co., Ltd., MSD KK, and Daiichi-Sankyo Company, Ltd., outside the submitted work. NoS reports personal fees from Daiichi Sankyo Co., Ltd, outside the submitted work. The authors report no other conflicts of interest in this work.

Author contributions

YO, NaS, and TN contributed to the conception and design of the study. YO contributed to the acquisition of data, analyzed the data, and wrote the article. All authors contributed toward data analysis, drafting and revising the paper and agree to be accountable for all aspects of the work.