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Abstract

Introduction: Age is an independent risk factor for mortality in critically ill patients. It is unclear if advances in critical care have favorably impacted mortality in older patients. Hypothesis: The purpose of this study was to determine the reliability of APACHE II in predicting mortality in critically ill surgical patients? 65 years of age. Methods: Retrospective analysis of outcomes of consecutive admissions to the SICU at an 800 bed Level 1, tertiary referral hospital from January thru December 2011 was performed. Data collected from the Surgical Critical Care database using ICUTracker™ included age, gender, ICU/hospital length of stay (LOS), mortality and severity of illness indicators (APACHE II score). Subgroup comparisons of mortality and severity of illness for each of the three surgical ICUs (neuroscience, cardiothoracic surgery and general surgery) was also performed. Age was dichotomized at 65 years (older? 65 years, younger < 65 years). Results: During the study period, 3077 patients were admitted to the SICU; of these 1892 had complete records available for review and were discharged prior to the end of the study period. Mean age of older patients (n=1153) was 76 ± 8 years and 50 ± 12 years for younger patients (n=737). Overall mortality was significantly higher for older patients (13% vs. 9%, P=0.01) as were APACHE II scores (20 ± 7 vs. 18 ± 8, older vs. younger, P<0.001). Sub-group comparisons for each ICU showed similar differences for APACHE II but higher mortality only in the neuroscience ICU (17% vs. 12%, older vs. younger, P=0.04). Interestingly, observed mortality was significantly (P<0.0001) lower than predicted mortality for older and younger age groups across each APACHE II breakpoint for mortality (95% CI). In fact, for the sickest patients (APACHE II > 34), the observed mortality of 55% was significantly (CI 35-74, P<0.0001) lower than the 85% mortality predicted by APACHE II. Conclusions: Survival outcomes for critically ill surgical patients consistently outperformed benchmark predictions by APACHE II independent of age. Resource utilization for intensive care for elderly patients is justified based on survival to discharge outcomes at a level 1, tertiary referral center.