Comparative performance of three comorbidity scores in predicting survival after the elective repair of abdominal aortic aneurysms.

Abstract

We aimed to study the discriminative power of 3 comorbidity scores for predicting 5-year survival after the elective repair of aorto-iliac aneurysms (AAA). 444 patients with AAA undergoing elective repair (33% open and 67% endovascular) between 2000 and 2020 were reviewed. The Charlson Comorbidity Index (CCI) and subsequent adjustments by Schneeweiss, Quan and Armitage, the Modified Frailty Index (MFI) and the American Society of Anesthesiologists Score (ASA) were calculated from preoperative data. Their association with 5-year survival was analyzed using Cox regression models and their discriminative power and its changes with C statistics and Net Reclassification Index (NRI). All comorbidity scores were associated with survival after adjusting by age, sex and type of surgical repair: original CCI HR=1.24, P<0.001; Schneeweiss CCI HR=1.23, P<0.001; Quan CCI HR=1.27, P<0.001, Armitage CCI HR=1.46, P<0.001, MFI HR=1.39, P<0.001 and ASA HR=1.68 (P=0.04) and 2.86 (P=0.01) for classes III and IV, respectively. Associated C statistics were of 0.64, 0.65, 0.65, 0.64, 0.61 and 0.59, respectively. Compared with the original CCI, models based on Schneeweiss CCI and Armitage CCI provided minor improvements in NRI (0.32 and 0.23), and the model based on ASA showed lower C statistics (P=0.014) and NRI (-0.30). Established comorbidity scores, such as CCI, MFI or ASA, are all associated with 5-year survival after the elective repair of AAAs, being ASA the worst of them. However, their predictive power is in no case sufficient to identify, by themselves, those patients who may not be eligible for intervention on the basis of life expectancy.