Objective: Undernutrition is frequently encountered in children with juvenile rheumatoid arthritis (JRA). We assessed resting energy expenditure (REE) in relation to nutritional status and body composition in patients with JRA.
Methods: We selected 33 children (age 6 to 18 yrs) with JRA (13 oligoarticular, 10 polyarticular, 10 systemic JRA) and 17 controls matched for age and sex. Nutritional status was assessed for height, weight, and fat-free mass (FFM), and REE was measured with indirect calorimetry.
Results: Nutritional status in the patients with systemic JRA was diminished compared to the controls for height (140 vs. 159 cm; p<0.01) and FFM (28 vs. 38 kg; p = 0.03). Oligo and polyarticular patients with JRA had normal height and FFM. No significant differences existed in crude REE among the groups. However, after correcting REE for body weight and FFM, the patients with systemic JRA, compared to controls, had 18% higher REE per kg body weight (159 vs. 134 kJ/kg/day; p<0.01) and 21% higher REE per kg FFM (196 vs. 162 kJ/kg/day; p<0.01). Oligo and polyarticular JRA patients had 8% increased values for REE per kg body weight or FFM, but these differences were not statistically significant.
Conclusion: Patients with systemic JRA show stunting, low FFM, and a significantly increased REE when nutritional status is taken into account. These data suggest that assessment of individual energy requirements should include correction for fat-free mass in the treatment of malnutrition in patients with systemic JRA.