Resting energy expenditure during spinal cord injury rehabilitation and utility of fat-free mass-based energy prediction equations: a pilot study

Abstract

Study design: Longitudinal observational study. Measurements were undertaken between weeks 4-6 post-spinal cord injury (SCI), repeated at week 8 and every 4 weeks thereafter until week 20 or rehabilitation discharge, whichever occurred first.

Objectives: Observe variation in measured resting energy expenditure (REE) and body composition in males undergoing SCI rehabilitation, compare REE with SCI-specific prediction equations incorporating fat-free mass (FFM), and explore the prevalence of clinical factors that may influence individual REE.

Setting: Spinal Injuries Unit, Brisbane, Queensland, Australia.

Methods: Indirect calorimetry was used to measure REE and bioimpedance spectroscopy to assess body composition. Four SCI-specific FFM-based REE and basal metabolic rate (BMR) prediction equations were compared to measured REE. A clinically significant change in REE was defined as +/- 10% difference from the week 4-6 measurement. Clinical factors that may affect REE variations were collected including infection, pressure injuries, autonomic dysreflexia, spasticity, and medications.

Results: Fifteen people participated (mean age 35 ± 13 years, 67% paraplegic). There was no statistically significant change in mean REE, weight, or body composition, and the Chun and Nightingale BMR prediction equations performed best (r_c > 0.8 at all time points). One-third of participants had >10% change in REE on 11 occasions, with clinical factors not consistently associated with the observed changes.

Conclusion: During SCI rehabilitation, mean REE, weight, and body composition remain unchanged, and FFM-based BMR prediction equations may be an acceptable alternative to indirect calorimetry. Future research designs should avoid single indirect calorimetry measures as snapshot data may not represent typical REE in this population.

Fig. 1. Change in resting energy expenditure (REE) throughout rehabilitation.

A Mean REE at each time point. Error bars represent the standard deviation and grey lines represent the REE of individual participants. B Percentage change in each participant’s REE at each time point compared to the week 4–6 measurement. The dotted grey line represents +/– 10% of the week 4–6 REE measurement, where a change >10% is considered clinically significant.

Fig. 2. Change in body weight and body composition during rehabilitation.

A Body weight, B fat-free mass % and C fat mass %. Error bars represent the standard deviation and grey lines represent the data of individual participants.