The AFC score: Validation of a 4-item predicting score of postoperative mortality after colorectal resection for cancer or diverticulitis - Results of a prospective multicenter study in 1049 patients

Objective: The aim of the present prospective study was to validate externally a 4-item predictive score of mortality after colorectal surgery (the AFC score) by testing its generalizability on a new population. Summary Background Data: We have recently reported, in a French prospective multicenter study, that age older than 70 years, neurologic comorbidity, underweight (body weight loss > 10% in < 6 months), and emergency surgery significantly increased postoperative mortality after resection for cancer or diverticulitis. Patients and Methods: From June to September 2004, 1049 consecutive patients (548 men and 499 women) with a mean age of 67 +/- 14 years, undergoing open or laparoscopic colorectal resection, were prospectively included. The AFC score was validated in this population. We assessed also the predictive value of other scores, such as the "Glasgow" score and the ASA score. To express and compare the predictive value of the different scores, a receiver operating characteristic curve was calculated. Results: Postoperative mortality rate was 4.6%. Variables already identified as predictors of mortality and used in the AFC score were also found to be associated with a high odds ratio in this study: emergency surgery, body weight loss > 10%, neurologic comorbidity, and age older than 70 years in a multivariate logistic model. The validity of the AFC score in this population was found very high based both on the Hosmer-Lemeshow goodness of fit test (P = 0.37) and on the area under the ROC curve (0.89). We also found that discriminatory capacity was higher than other currently used risk scoring systems such as the Glasgow or ASA score. Conclusion: The present prospective study validated the AFC score as a pertinent predictive score of postoperative mortality after colorectal surgery. Because it is based on only 4 risk factors, the AFC score can be used in daily practice.