SUN-650 Body Composition Assessment in Clinical Practice: Use in Rheumatoid Arthritis and Hypogonadism

BACKGROUND: DXA is an accessible, non-invasive method, also used for body composition assessment, standing out for regional composition analysis. In clinical practice, the analysis of body composition is relevant by differentiating lean (fat-free) mass from fat mass. The higher the fat to lean mass ratio, the greater the obesity-related comorbidities. CLINICAL CASE: Case 1: A 22-year-old male, BMI 21kg/m2, with rheumatoid arthritis (RA) and on chronic glucocorticoid (GC) performed a DXA to evaluated body composition. The first analysis, during GC use, showed 26.1% fat (14.6kg) despite the low BMI. The patient, evolved stable from RA, and was able to stay out of GC for 2 years, with no other interventions. A new DXA showed a decrease in fat percentage to 12.6% (6.2kg), a reduction in total body weight (-7kg) and an increase in lean mass (+1.2kg). Within 16 months of GC reintroduction, the fat percentage increased up to 36.8% (23.8kg), the total weight increased by 15.6kg and the lean mass decreased by 2.1kg. Case 2: A 40-year-old male with hypogonadism showed 37% fat (33.8kg) on ​​first DXA evaluation. Testosterone replacement was started, and a new DXA was performed after 10 weeks, and although the total weight increased by 3.1kg, there was a decrease in fat mass to 33.5% (31.6kg) and an increase of 5.3kg in lean mass. After 3 years, there was a reduction to 27.1% of fat (24.5kg) and, after 4 years of therapy initiation, the percentage of fat was 26.9% (24.5kg). There was no change in diet or exercise. CONCLUSION: The exposed cases highlight the importance of body composition assessment in patients with conditions that interferes with energy metabolism. The patient on chronic GC use, after medication withdrawal, presented a significant decrease in fat mass, more pronounced in the android percentage. The reintroduction of the CG showed an increase in fat percentage, with android predominance. The patient with hypogonadism, in the second evaluation performed with only 10 weeks of treatment with testosterone, evolved with a reduction in fat mass associated with an increase in lean mass, besides a reduction in the android percentage. The reported cases illustrate everyday clinical situations in which disease vs. treatment significantly changes body composition. Assessment of body composition is essential in patients exposed to conditions that interfere with energy metabolism since obesity is associated with chronic comorbidities and cardiovascular outcomes.