Sarcopenia increases risk of long-term mortality in elderly patients undergoing emergency abdominal surgery

BACKGROUND: Frailty is associated with poor surgical outcomes in elderly patients but is difficult to measure in the emergency setting. Sarcopenia, or the loss of lean muscle mass, is a surrogate for frailty and can be measured using cross-sectional imaging. We sought to determine the impact of sarcopenia on 1-year mortality after emergency abdominal surgery in elderly patients. METHODS: Sarcopenia was assessed in patients 70 years or older who underwent emergency abdominal surgery at a single hospital from 2006 to 2011. Average bilateral psoas muscle cross-sectional area at L3, normalized for height (Total Psoas Index TPI), was calculated using computed tomography. Sarcopenia was defined as TPI in the lowest sex-specific quartile. Primary outcome was mortality at 1 year. Secondary outcomes were in-hospital mortality and mortality at 30, 90, and 180 days. The association of sarcopenia with mortality was assessed using Cox proportional hazards regression and model performance judged using Harrell's C-statistic. RESULTS: Two hundred ninety-seven of 390 emergency abdominal surgery patients had preoperative imaging and height. The median age was 79 years, and 1-year mortality was 32%. Sarcopenic and nonsarcopenic patients were comparable in age, sex, race, comorbidities, American Society of Anesthesiologists classification, procedure urgency and type, operative severity, and need for discharge to a nursing facility. Sarcopenic patients had lower body mass index, greater need for intensive care, and longer hospital length of stay (p < 0.05). Sarcopenia was independently associated with increased in-hospital mortality (risk ratio, 2.6; 95% confidence interval CI, 1.6-3.7) and mortality at 30 days (hazard ratio HR, 3.7; 95% CI, 1.9-7.4), 90 days (HR, 3.3; 95% CI, 1.8-6.0), 180 days (HR, 2.5; 95% CI, 1.4-4.4), and 1 year (HR, 2.4; 95% CI, 1.4-3.9). CONCLUSION: Sarcopenia is associated with increased risk of mortality over 1 year in elderly patients undergoing emergency abdominal surgery. Sarcopenia defined by TPI is a simple and objective measure of frailty that identifies vulnerable patients for improved preoperative counseling, setting realistic goals of care, and consideration of less invasive approaches. LEVEL OF EVIDENCE: Prognostic study, level III.