Background: Weight variability (WV), or daily-to-weekly fluctuations in weight, associates with increased eating pathology in adults with bulimia nervosa and greater weight gain across the developmental span in healthy controls, but few studies have explored these relations in adolescents with anorexia nervosa (AN). Given the importance of early weight gain during treatment for AN prognosis, WV could impact outcomes via effects on weight trends and related psychopathology. The current study examined whether WV and the slope of weight change predict eating disorder symptoms at the end of treatment (EOT) among adolescents with AN.
Method: Adolescents with AN (N = 284) receiving residential treatment completed the Eating Disorder Examination Questionnaire (EDE-Q) at admission and EOT. WV was calculated using the root-mean-squared-error of daily weights over the first 14 days of treatment. Linear regressions examined the effect of WV, slope of weight change over 14 days, and their interaction on percent expected body weight (%EBW) and EDE-Q scores at EOT.
Results: WV positively predicted EDE-Q Global Score (p = 0.033, sr2 = 0.01), Shape Concern (p = 0.026, sr2 = 0.01), and Weight Concern (p = 0.008, sr2 = 0.02) at EOT. Neither WV nor the slope of weight change predicted %EBW at EOT (ps > 0.05). The slope of weight change did not predict EDE-Q, nor did it moderate the relation between WV and any outcomes (ps > 0.05).
Conclusions: Patients who experience greater weight fluctuations early in treatment may be more susceptible to elevated psychopathology at discharge. In light of few significant effects and small effect sizes, more research is needed to determine the putative role of early weight trends in adolescent AN outcomes.
Keywords: adolescence; anorexia nervosa; higher level of care; weight change; weight variability.
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