Are the general equations to predict BMR applicable to patients with anorexia nervosa?
OBJECTIVE
To determine whether the general equations to predict basal metabolic rate (BMR) can be reliably applied to female anorectics.


METHODS
Two hundred and thirty-seven female patients with anorexia nervosa (AN) were divided into an adolescent group [n=43, 13-17 yrs, 39.3+/-5.0 kg, body mass index (BMI) (weight/height) 15.5+/-1.8 kg/m2] and a young-adult group (n=194, 18-40 yrs, 40.5+/-6.1 kg, BMI 15.6+/-1.9 kg/m2). BMR values determined by indirect calorimetry were compared with those predicted according to either the WHO/FAO/UNU or the Harris-Benedict general equations, or using the Schebendach correction formula (proposed for adjusting the Harris-Benedict estimates in anorectics).


RESULTS
Measured BMR was 3,658+/-665 kJ/day in the adolescent and 3,907+/-760 kJ/day in the young-adult patients. In the adolescent group, the differences between predicted and measured values were (mean+/-SD) 1,466 529 kJ/day (+44+/-21%) for WHO/FAO/UNU, 1,587+/-552 kJ/day (+47+/-23%) for the Harris-Benedict and -20+/-510 kJ/day for the Schebendach (+1+/-13%), while in the young-adult group the corresponding values were 696+/-570 kJ/day (+24+/-24%), 1,252+/-644 kJ/day (+37+/-27%) and -430+/-640 kJ/day (-9+/-16%). The bias was negatively associated with weight and BMI in both groups when using the WHO/FAO/UNU and Harris-Benedict equations, and with age in the young-adult group for the Harris-Benedict and Schebendach equations.


CONCLUSIONS
The WHO/FAO/UNU and Harris-Benedict equations greatly overestimate BMR in AN. Accurate estimation is to some extent dependent on individual characteristics such as age, weight or BMI. The Schebendach correction formula accurately predicts BMR in female adolescents, but not in young adult women with AN.
Marra
M
M
Department of Clinical and Experimental Medicine, National Institute for Food and Nutrition Research, Federico II University, Naples, Italy.
Polito
A
A
De Filippo
E
E
Cuzzolaro
M
M
Ciarapica
D
D
Contaldo
F
F
Scalfi
L
L
D000293:Adolescent; D000328:Adult; D000465:Algorithms; D000704:Analysis of Variance; D000856:Anorexia Nervosa / Q000378:metabolism*; D001481:Basal Metabolism; D002153:Calorimetry, Indirect; D005260:Female; D006801:Humans; D015203:Reproducibility of Results