In-hospital mortality for liver resection for metastases: a simple risk score.

BACKGROUND: Surgical management of liver metastases from various primaries is increasingly common. The mortality of such procedures is not well-defined. Accurate predictions for perioperative risk could augment decision-making.
MATERIALS AND METHODS: The Nationwide Inpatient Sample was queried (1998-2005) for patient-discharges for hepatic procedures for metastases. Logistic regression and bootstrap methods were used to create an integer score for estimating the risk of in-hospital mortality using patient demographics, comorbidities, procedure, and hospital type. A randomly selected sample of 80% of the cohort was used to create the risk score, with validation of the score in the remaining 20%.
RESULTS: For the total 50,537 patient-discharges, overall in-hospital mortality was 2.6%. Factors included in the model were age, sex, Charlson comorbidity score, procedure type, and teaching hospital status. Integer values were assigned for calculating an additive score. Four score groups were assembled to stratify risk, with a 15-fold gradient of mortality ranging from 0.9% to 14.7% (P<0.0001). In the derivation and the validation set, the score discriminated well, with a c-statistic of 0.72 and 0.72, respectively.
CONCLUSION: An integer-based risk score can be used to predict in-hospital mortality after hepatic procedure for metastases, and may be useful for preoperative patient counseling.