Risk Adjustment for CABG surgery: an administrative approach versus Euroscore

OBJECTIVE. To determine the ability of administrative data in predicting mortality for patients undergoing coronary artery bypass graft surgery (CABG). METHODS.Administrative databases on hospital discharge abstracts (SDO) of the Italian region Emilia Romagna and death registry data for year 2000. We used a multivariate logistic regression analysis to compare an ICD-9-CM risk adjustment approach based on administrative variables (such as age, gender, principal diagnosis, combined operation, previous cardiac surgery, emergency admission and Charlson comorbidity index) with a risk adjustment approach based on the clinical Euroscore to predict in-hospital and 60-day mortality and to assess hospital performance. Results. The risk adjustment approach based on ICD-9-CM data provides good explanatory ability in models assessing outcomes (the c statistics obtained are very close, c= 0.78 for in-hospital mortality in both approaches and c = 0.78 for the administrative model vs. 0.79 for the clinical one, considering 60-day mortality). CONCLUSIONS. With the growing completeness and accuracy of administrative data, this result seems to be of particular importance if we consider the possibility of adapting and applying administrative approaches to illnesses other than cardiovascular diseases, for which several clinical risk indexes - such as Euroscore - have been successfully developed.