J Prev Med Public Health.  2014 Jul;47(4):206-215. 10.3961/jpmph.2014.47.4.206.

Variations in the Hospital Standardized Mortality Ratios in Korea

• Lee EJ
• Hwang SH
• Lee JA
• Kim Y

• KMID: 2381418
• DOI: http://doi.org/10.3961/jpmph.2014.47.4.206

Abstract

OBJECTIVES
The hospital standardized mortality ratio (HSMR) has been widely used because it allows for robust risk adjustment using administrative data and is important for improving the quality of patient care.
METHODS
All inpatients discharged from hospitals with more than 700 beds (66 hospitals) in 2008 were eligible for inclusion. Using the claims data, 29 most responsible diagnosis (MRDx), accounting for 80% of all inpatient deaths among these hospitals, were identified, and inpatients with those MRDx were selected. The final study population included 703 571 inpatients including 27 718 (3.9% of all inpatients) in-hospital deaths. Using logistic regression, risk-adjusted models for predicting in-hospital mortality were created for each MRDx. The HSMR of individual hospitals was calculated for each MRDx using the model coefficients. The models included age, gender, income level, urgency of admission, diagnosis codes, disease-specific risk factors, and comorbidities. The Elixhauser comorbidity index was used to adjust for comorbidities.
RESULTS
For 26 out of 29 MRDx, the c-statistics of these mortality prediction models were higher than 0.8 indicating excellent discriminative power. The HSMR greatly varied across hospitals and disease groups. The academic status of the hospital was the only factor significantly associated with the HSMR.
CONCLUSIONS
We found a large variation in HSMR among hospitals; therefore, efforts to reduce these variations including continuous monitoring and regular disclosure of the HSMR are required.

Keyword

Quality of health care; Outcome assessment; Hospital mortality

MeSH Terms

*Hospital Mortality
Hospitals/*statistics & numerical data
Humans
Logistic Models
Outcome Assessment (Health Care)/standards
Quality of Health Care/standards
Republic of Korea