J Prev Med Public Health.  2013 Mar;46(2):74-81.

Improving the Performance of Risk-adjusted Mortality Modeling for Colorectal Cancer Surgery by Combining Claims Data and Clinical Data

• Jang WM
• Park JH
• Park JH
• Oh JH
• Kim Y

Abstract

OBJECTIVES
The objective of this study was to evaluate the performance of risk-adjusted mortality models for colorectal cancer surgery.
METHODS
We investigated patients (n=652) who had undergone colorectal cancer surgery (colectomy, colectomy of the rectum and sigmoid colon, total colectomy, total proctectomy) at five teaching hospitals during 2008. Mortality was defined as 30-day or in-hospital surgical mortality. Risk-adjusted mortality models were constructed using claims data (basic model) with the addition of TNM staging (TNM model), physiological data (physiological model), surgical data (surgical model), or all clinical data (composite model). Multiple logistic regression analysis was performed to develop the risk-adjustment models. To compare the performance of the models, both c-statistics using Hanley-McNeil pair-wise testing and the ratio of the observed to the expected mortality within quartiles of mortality risk were evaluated to assess the abilities of discrimination and calibration.
RESULTS
The physiological model (c=0.92), surgical model (c=0.92), and composite model (c=0.93) displayed a similar improvement in discrimination, whereas the TNM model (c=0.87) displayed little improvement over the basic model (c=0.86). The discriminatory power of the models did not differ by the Hanley-McNeil test (p>0.05). Within each quartile of mortality, the composite and surgical models displayed an expected mortality ratio close to 1.
CONCLUSIONS
The addition of clinical data to claims data efficiently enhances the performance of the risk-adjusted postoperative mortality models in colorectal cancer surgery. We recommended that the performance of models should be evaluated through both discrimination and calibration.

Keyword

Quality of health care; Colorectal neoplasms; Colorectal surgery

MeSH Terms

Adult
Aged
Colorectal Neoplasms/*mortality/surgery
Databases, Factual
Female
Hospital Mortality
Hospitals, Teaching
Humans
Logistic Models
Male
Middle Aged
Models, Psychological
*Models, Theoretical
Neoplasm Staging
Odds Ratio
Quality of Health Care
Risk Adjustment