Effect of obesity and decompressive laparotomy on mortality in acute pancreatitis requiring intensive care unit admission

Background: Controversy still exists on the effect that obesity has on the morbidity and mortality in severe acute pancreatitis (SAP). The primary purpose of this study was to compare the mortality rate of obese versus nonobese patients admitted to the ICU for SAP. Secondary goals were to assess the potential risk factors for abdominal compartment syndrome (ACS) and to investigate the performance of validated scoring systems to predict ACS and in-hospital mortality. Methods: A retrospective cohort of adults admitted to the ICU for SAP was stratified by their body mass index (BMI) as obese and nonobese. The rates of morbidity, mortality, and ACS were compared by univariate and multivariate regression analyses. Areas under the curve (AUC) were used to evaluate the discriminating performance of severity scores and other selected variables to predict mortality and the risk of ACS. Result: Forty-five patients satisfied the inclusion criteria and 24 (53 %) were obese with similar characteristics to nonobese patients. Among all the subjects, 11 (24 %) died and 16 (35 %) developed ACS. In-hospital mortality was significantly lower for obese patients (12.5 vs. 38 %; P = 0.046) even though they seemed to develop ACS more frequently (41 vs. 28 %; P = 0.533). At multivariable analysis, age was the most significant factor associated with in-hospital mortality (odds ratio (OR) = 1.273; 95 % confidence interval (CI) 1.052-1.541; P = 0.013) and APACHE II and Glasgow-Imrie for the development of ACS (OR = 1.143; 95 % CI 1.012-1.292; P = 0.032 and OR = 1.221; 95 % CI 1.000-1.493; P = 0.05) respectively. Good discrimination for in-hospital mortality was observed for patients' age (AUC = 0.846) and number of comorbidities (AUC = 0.801). ACS was not adequately predicted by any of the clinical severity scores (AUC = 0.548-0.661). Conclusions: Patients' age was the most significant factor associated with mortality in patients affected by SAP. Higher APACHE II and Glasgow-Imrie scores were associated with the development of ACS, but their discrimination performance was unsatisfactory.