Descriptive Study of Body Composition Abnormalities and Health Risks in Patients with Obesity

Background: Body composition abnormalities are independent predictors of health outcomes in a variety of disease states. The simultaneous condition of low muscle mass and high fat mass, termed sarcopenic obesity, is an abnormal body composition phenotype associated with metabolic abnormalities and co-morbidities. Objectives: The purpose of this study was to investigate the overall body composition variability among obese patients, and to compare health characteristics between sarcopenic obese and non-sarcopenic obese patients. Methods: In this retrospective, chart review study, patients ( ≥18 years old) seeking weight loss treatment at a local center in Tallahassee, FL and with available baseline bio-electrical impedance analysis (BIA) data on file were included in this study. The ratio between fat mass index [FMI, defined as fat mass (kg) / height (m2)] and fat free mass index [FFMI, defined as fat free mass (kg)/height (m2)] were used to define sarcopenic obesity. Medical records were further reviewed for information on metabolic profile and health status. Results: Ninety-one obese patients with a mean age of 57 ± 11 years were included in this study. Body mass index (BMI) ranged from 31.6 to 68.7 kg/m2. Eighty-one percent were morbidly obese. The FMI/FFMI ratio was variable ranging from 0.35 to 2.46 kg/m2, independent of body weight. A gender-specific FMI/FFMI ratio above the median was used to depict the sarcopenic obesity phenotype. This corresponded to: FMI/FFMI ≥ 1.05 kg/m2 in women and FMI/FFMI ≥ 0.78 kg/m2 in men. As expected, men presented with higher body weight, height, waist circumference and FFMI, compared to women. On the contrary, women presented with higher percent body fat and FMI/FFMI ratio. No gender differences were observed for body mass index (BMI), fat mass and FMI. Plasma albumin concentration was lower in sarcopenic obese patients compared to non-sarcopenic obese patients (p=0.032). Sarcopenic obese patients reported a higher prevalence of low back pain compared to their counterparts. In fact, sarcopenic obesity was the strongest predictor of low back pain, with an odds ratio of 2.3 (95% CI=1.01-5.41, P=0.048). Similarly, the prevalence of alcoholism and sexual dysfunction were significantly greater among sarcopenic obese patients compared to non-sarcopenic obese patients (P=0.026 and P=0.030, respectively). Conclusion: A wide variability in body composition was observed in this cohort of patients, illustrating how the proportions of fat to fat-free tissues may differ among patients with similar BMI. We suggest the use of the FMI/FFMI ratio as a potential approach for the assessment of sarcopenic obesity in patients with severe obesity. Using this approach, patients with a sarcopenic obesity phenotype presented with higher risk of certain metabolic abnormalities and comorbidities.