Estimating the Basal metabolic rate from fat free mass in individuals with motor complete spinal cord injury

Study design: Cross-sectional study. Objectives: This study aimed to validate the existing basal metabolic rate (BMR) predictive equations that include fat free mass (FFM) as an independent variable and, based on the FFM assessment, to develop a new SCI population-specific equation. Setting: Outpatient clinic in a general hospital. Methods: Our study group was formed of 50 individuals with chronic motor complete SCI: 27 patients with tetraplegia and 23 with paraplegia. Both BMR and FFM values were measured by indirect calorimetry (IC) and the whole-body dual energy X-ray absorptiometry, respectively. The BMR values measured by IC were compared with the values estimated from the Cunningham equation. Multiple linear regression analysis was performed to develop a new FFM-based, BMR predictive equation. Results: The mean value of BMR measured by IC was 1274.8 (s.d. = 235.2) kcal day(-1). The intra-class correlation coefficient (ICC) between values measured by IC and estimated from the Cunningham equation was 0.845 and the limits of agreement ranged from -30.6 to 241.3 kcal. SCI population specific BMR predictive equation was developed; BMR (kcal day(-1))= 24.5x FFM(kg)+244.4. The newly developed equation showed ICC of 0.866 with the limits of agreement from -229.0 to 233.1 kcal day(-1). Conclusions: A considerable bias from the BMR values measured by IC was still observed, which warrants clinical consideration when applying FFM-based BMR prediction equations to individuals with SCI.