Scientific paper Evaluating alternative risk-adjustment strategies for surgery Adam Atherly, Ph.D. a, *, Aaron S. Fink, M.D. b,c , Darrell C. Campbell, M.D. d , Robert M. Mentzer, Jr., M.D. e , William Henderson, Ph.D. f , Shukri Khuri, M.D. g,h , Steven D. Culler, Ph.D. a a Department of Health Policy and Management, Rollins School of Public Health, Emory University, 1518 Clifton Rd. N.E., Atlanta, GA 30322, USA b Department of Surgery, Emory University School of Medicine, Atlanta, GA, USA c Surgical Service, Atlanta VA Medical Center, Atlanta, GA, USA d Department of Surgery and Office of Clinical Affairs, University of Michigan Medical Center, Ann Arbor, MI, USA e Department of Surgery, University of Kentucky, Lexington, KY, USA f Colorado Health Outcomes Program, University of Colorado, Denver, CO, USA g Department of Surgery, West Roxbury VAMC, West Roxbury, MA, USA h Harvard Medical School, Boston, MA, USA Manuscript received June 10, 2004; revised manuscript July 3, 2004 Presented at the 28th Annual Symposium of the Association of VA Surgeons, Richmond, Virginia, April 25–27, 2004 Abstract 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. Conclusion: In surgical patients, different risk-adjustment methodologies afford divergent estimates of mortality risk. © 2004 Excerpta Medica Inc. All rights reserved. Keywords: Mortality; National Surgical Quality Improvement Program; Risk adjustment; Surgical outcomes Evidence-based medicine and medical error reduction have become new buzz words in today’s health care arena. Policy makers, financiers, and purchasers of health care now de- mand increased evidence of value for their health care dollars. This demand has lead to new efforts to evaluate the quality of care provided by health care purchasers, organi- zations, and providers. Yet although there is tremendous interest in comparing outcomes across organizations and providers, the movement has been stymied by the method- ologic obstacles in such comparisons. In response to this problem, considerable effort has been devoted to the development of risk-adjustment techniques. These tools aim to control for differences in patient char- acteristics and clinical factors associated with the outcome of interest, but these differences are out of the organiza- tion’s control. For example, a diabetic patient is more likely to experience postoperative complications than a nondia- betic patient, all other factors held equal. The purpose of this study was to examine the compara- bility of several risk-adjustment methodologies: the Na- tional Surgical Quality Improvement Program (NSQIP), * Corresponding author. Tel.: +1-404-727-1175; fax: +1-404-727- 9198. E-mail address: aatherl@sph.emory.edu The American Journal of Surgery 188 (2004) 566 –570 0002-9610/04/$ – see front matter © 2004 Excerpta Medica Inc. All rights reserved. doi:10.1016/j.amjsurg.2004.07.032