Basal metabolic rate in morbidly obese patients with non-alcoholic fatty liver disease.

BACKGROUND Non-Alcoholic Fatty Liver Disease occurs mainly in severly obese patients and its relationship to Metabolic Syndrome is increasingly recognized. The aim of this study was to determine energy production-utilization by measuring the Basal Metabolic Rate in severely obese patients, characterized by NAFLD, with or without Metabolic Syndrome. Then, the role of systemic inflammation was assessed. PATIENTS AND METHODS Twenty severly obese men with Metabolic Syndrome were compared with a well-matched cohort of patients without Metabolic Syndrome. All showed hepatic steatosis at UltraSonography. Basal Metabolic Rate was measured by indirect calorimetry using a canopy system and single-frequency bio-impedance analysis. Serum Interleukin-6 and fibrinogen levels were measured as markers of inflammation RESULTS Basal Metabolic Rate was higher in severely obese patients with Metabolic Syndrome than in those without it: 2,496+/-358 kcal/d vs 2,126+/-253 kcal/d, P = 0 .001. Laboratory findings of concurrent chronic inflammation were also higher in these patients, i.e., Il6 4.35+/-1.34 pg/ml vs 6.23+/-2.1 pg/ml, P = 0.034; fibrinogenemia 285+/-40 mg/dL vs 376+/-91 mg/dL, P = 0.020; these of of cytonecrosis, i.e., AlaninaminoTransferase, equally behaved 32.3+/-7.9 UI vs 65.7+/-28.2 UI, P < 0.001. Visceral adiposity and arterial hypertension were more frequently detected in patients with Metabolic Syndrome. CONCLUSION Increased energy expenditure, observed in morbidly obese patients as a consequence of a systemic, low-grade, inflammatory process, may explain progression from obesity to Metabolic Syndrome, independent of the presence of NAFLD. In this context, increased Basal Metabolic Rate may be a clue of Metabolic Syndrome.