Severity-Adjusted Mortality Rates of Coronary Artery Bypass Graft Surgery Using MedisGroups

Kwon, Young-Dae

Journal of Korean Society Quality Assurance Health Care 2000;7(2): 218.
Published online December 30, 2000.

MedisGroups를 이용한 관상동맥우회술의 중증도 보정사망률에 관한 연구

권영대

경희대학교 의료경영학과

Severity-Adjusted Mortality Rates of Coronary Artery Bypass Graft Surgery Using MedisGroups

Young-Dae Kwon

Department of Health Services Management, Kyunghee University

Abstract

Background
Among 'structure', 'process' and 'outcome' approaches, outcome evaluation is considered as the most direct and best approach to assess the quality of health care providers. Risk-adjustment is an essential method to compare outcome across providers. This study has aims to judge performance of hospitals by severity adjusted mortality rates of coronary artery bypass graft (CABG) surgery.
Methods
Medical records of 584 patients who got the CABG surgery in 6 general hospitals during 1996 and 1997 were reviewed by trained nurses. The MedisGroups was used to quantify severity of patients. The predictive probability of death was calculated for each patient in the sample from a multivariate logistic regression model including the severity score, age and sex. For evaluation of hospital performance, we calculated ratio of observed number to expected number of deaths and z score [(observed number of deaths - expected number of deaths)/square root of the variance in the number of deaths], and compared observed mortality rate with confidence interval of adjusted mortality rate for each hospital.
Results
The overall in-hospital mortality was 7.0%, ranged from 2.7% to 15.7% by hospital. After severity adjustment the mortality by hospital was from 2.7% to 10.7%. One hospital with poor performance was distinctly divided from others with good performance.
Conclusion
In conclusion, severity-adjusted mortality rate of CABG surgery might be applied as an indicator for hospital performance evaluation in Korea. But more pilot studies and improvement of methodologies has to be done to use it as quality indicator.

Key words Severity adjustment;Mortality rate;Coronary artery bypass graft surgery;MedisGroups;Hospital performance;