The association between leptin and weight maintenance outcome in anorexia nervosa

Objective: Relapse after weight restoration in anorexia nervosa (AN) is a critical problem. Higher body fat percentage after weight gain has been shown to predict better weight maintenance outcome. Leptin, a fat-derived hormone, has been associated with progress during weight gain, but its association with weight maintenance is unknown. This study aims to determine whether leptin levels after weight restoration in AN are associated with weight maintenance. Method: Participants were 41 women with AN hospitalized for inpatient treatment. Participants were evaluated 2–4 weeks after weight restoration to body mass index (BMI) ≥ 19.5 kg/m² for plasma leptin and body composition. Weight maintenance outcome was defined by whether a participant maintained a BMI of at least 18.5 kg/m² at the end of 1 year following hospital discharge. Results: Twenty (48.8%) out of 41 patients maintained their weight at 1 year. Percent body fat and leptin were significantly higher in the group who maintained weight (body fat, p =.004, Hedges' g = 0.944; log-leptin, p =.010, Hedges' g = 0.821), but there were no differences in predischarge BMI, duration of illness, and duration of amenorrhea. Using regression modeling, only higher log-leptin (p_Wald =.021) and percent body fat (p_Wald =.010), as well as fat-adjusted leptin (p_Wald =.029), independently predicted weight maintenance at 1 year. Discussions: Our findings suggest that for acutely-weight restored women with AN, higher predischarge leptin measurements are associated with better outcome in the year following treatment. Prospective studies examining leptin as well as other parameters of metabolic health could offer insights into biomarkers that may improve clinical outcomes.