A leptin serum concentration less than 10 ng/ml is a predictive marker of outcome in patients with moderate to severe secondary peritonitis

Introduction: Leptin is involved in the sepsis syndrome. A possible relationship exists between low leptin levels and peritonitis severity and a poorer prognosis. Objectives: We aimed to corroborate the relationship between low leptin serum levels and death in patients with peritonitis and to explore the associations between leptin and interleukin-6 (IL-6), interleukin-10 (IL-10), interleukin-13 (IL-13), tumor necrosis factor-alpha (TNF-alpha) and C-reactive protein (CRP). Methods: In 230 adult patients with surgically confirmed secondary peritonitis, the Mannheim Peritonitis Index and the serum concentrations of leptin, IL-6, IL-10, IL-13, TNF-alpha and CRP were determined. Two cohorts were established (leptin <= 10 ng/ml and > 10 ng/ml). Death or survival was followed through 30 days. The relationship between leptin (<= 10 ng/ml) and death was evaluated using the accumulated incidence ratio (AIR). The association of leptin (dependent variable) with IL-6, IL-10, IL-13, TNF-alpha and CRP (independent variables) was studied by regression analysis. Results: The general mortality rate was 7.8% and the death AIR was 3.15 (p nonsignificant). A subsample of patients with a Mannheim Peritonitis Index >= 21 was studied, showing a significant AIR of 4.26 (p = 0.017). Regression analysis determined an association only between leptin and IL-6 (p < 0.001), IL-10 (p < 0.047) and CRP (p < 0.001). Discussion: A serum leptin below the threshold of 10 ng/ml is an adverse prognostic marker in patients with moderate to severe secondary peritonitis. The results of the regression analysis suggest that the mechanisms involved are opposing, in that leptin associated with IL-6 has a proinflammatory effect and, through IL-10 and CRP production, restrains the inflammatory response. Copyright (C) 2008 S. Karger AG, Basel.