OBJECTIVES: Evaluation of the prognostic ability of the APACHE-AAA model in an independent group of post-operative (open) Abdominal Aortic Aneurysm (AAA) patients. METHODS: The model was applied to predict in-hospital mortality in 541 patients (325 elective and 216 emergencies; 489 from Oxford; 52 from Lewisham). Multi-level modelling was used to adjust for both the local structure and process of care and patient case-mix. Model performance was assessed using goodness-of-fit and subgroup analyses. RESULTS: The model's predictive ability to discriminate between dead and alive patients was very good (ROC area=0.84). The model achieved a good fit across all strata of risk (Hosmer-Lemeshow C-test (8, N=476)=7.777, p=0.456) and in all subgroups. The model was able to rank the ICUs according to their performance independently of the patient case-mix. CONCLUSION: The APACHE-AAA model accurately predicted in-hospital mortality in a population of patients independent of the one used to develop it, confirming its validity. The multi-level methodology employed has shown that patient outcome is not only a function of the patient case-mix but instead predictive models should also adjust for the individual hospital-related factors (structure and process of care).
Eur J Vasc Endovasc Surg
514 - 521
APACHE, Aged, Aged, 80 and over, Aortic Aneurysm, Abdominal, Discriminant Analysis, England, Female, Hospital Mortality, Humans, Logistic Models, Male, Models, Statistical, Outcome Assessment (Health Care), Prognosis, ROC Curve, Risk Assessment, Severity of Illness Index