RESUMEN
OBJECTIVES: Anorexia nervosa (AN) is a complex disease that involves malnutrition and a profound depletion in muscle mass. The thickness of the adductor pollicis muscle (APM) has been proposed as a new anthropometric technique to estimate muscle mass, check early changes, and assess its evaluation. This study aimed to evaluate the accuracy and validity of the APM thickness in a cohort of malnourished patients with AN when checking local mass gain. The Doppler ultrasound maybe an affordable and useful method to discriminate all tissues around the APM area. METHODS: A prospective cohort study was conducted of 31 malnourished patients with AN who were admitted to the Regional Eating Disorders Unit for treatment, including re-alimentation. Anthropometric measurements were taken, including arm circumference, triceps skinfold thickness, arm muscle circumference, body mass index, and APM thickness of both hands. Simultaneously, a Doppler ultrasound was performed in the same area, measuring and discriminating fat, skin, and muscle tissues around the APM. RESULTS: Nutritional improvement is accompanied by fat, but not muscle gain in the hand in the adductor pollicis area of patients with AN. A Doppler ultrasound can accurately discriminate between tissues around the APM. CONCLUSIONS: APM thickness reflects the addition of two different muscles plus fat and skin; therefore, this tool is not reliable to assess APM mass.