Comparison of body composition, basal metabolic rate and metabolic outcomes of adults with Prader Willi syndrome or lesional hypothalamic disease, with primary obesity.

CONTEXT: The care of patients with hypothalamic obesity is challenging.
OBJECTIVE: To compare body composition, basal metabolic rate (BMR) and metabolic outcomes of adults, with lesional or genetic hypothalamic obesity, with obese patients suffering from primary obesity, once matched for body mass index (BMI). DESIGN AND PATIENTS: Adults with hypothalamic obesity of genetic origin (Prader Willi syndrome (PWS)) or acquired hypothalamic damage (HD), such as craniopharygioma, were compared with obese control candidates awaiting bariatric surgery (C), with a BMI between 35 and 65 kg m(-)(2), and aged between 18 and 50 years. MAIN OUTCOME MEASURES: Body composition measured by whole-body dual-energy X-ray absorptiometry scanning, BMR using indirect calorimetry, hormonal and metabolic assessments.
RESULTS: A total of 27 adults with a genetic diagnosis of PWS, 15 obese subjects with HD and 206 obese controls with similar BMI were studied. Compared with the control group, PWS patients had an increased percentage of fat mass (FM), and a decreased percentage of android FM. The BMR of PWS patients was significantly lower than controls and highly correlated with lean body mass in PWS and C patients. Body composition of HD was similar with those of obese patients. A trend toward an increased prevalence of diabetes in HD patients and of cytolysis in PWS was observed in comparison with primary obese patients.
CONCLUSION: Genetic and lesional hypothalamic obesities have different consequences for phenotypic features such as body composition or BMR compared with primary obese patients. The mechanisms of adipose tissue development and metabolic complications may be different between genetic and lesional obesities.