Evaluating alternative risk-adjustment strategies for surgery.
BACKGROUND
Comparison of institutional health care outcomes requires risk adjustment. Risk-adjustment methodology may influence the results of such comparisons.


METHODS
We compared 3 risk-adjustment methodologies used to assess the quality of surgical care. Nurse reviewers abstracted data from a continuous sample of 2,167 surgical patients at 3 academic institutions. One risk adjustor was based on medical record data (National Surgical Quality Improvement Program [NSQIP]) whereas the other 2, the DxCG and Charlson Comorbidity Index (CCI), primarily used International Classification of Disease-9 (ICD-9) codes. Risk-assessment scores from the 3 systems were compared with each other and with mortality.


RESULTS
Substantial disagreement was found in the risk assessment calculated by the 3 methodologies. Although there was a weak association between the CCI and DxCG, neither correlated well with the NSQIP. The NSQIP was best able to predict mortality, followed by the DxCG and CCI.


CONCLUSIONS
In surgical patients, different risk-adjustment methodologies afford divergent estimates of mortality risk.
Atherly
Adam
A
Department of Health Policy and Management, Rollins School of Public Health, Emory University, 1518 Clifton Rd. N.E., Atlanta, GA 30322, USA. aather1@sph.emory.edu
Fink
Aaron S
AS
Campbell
Darrell C
DC
Mentzer
Robert M
RM
Henderson
William
W
Khuri
Shukri
S
Culler
Steven D
SD
D019317:Evidence-Based Medicine; D005260:Female; D019538:Health Care Surveys; D006801:Humans; D016015:Logistic Models; D008297:Male; D011785:Quality Assurance, Health Care; D012372:ROC Curve; D020379:Risk Adjustment; D012680:Sensitivity and Specificity; D013503:Surgery Department, Hospital / Q000592:standards*; D013514:Surgical Procedures, Operative / Q000401:mortality* / Q000592:standards*; D016019:Survival Analysis; D017749:Total Quality Management; D014481:United States