78. Estimating Goal Weights in Adolescents with Anorexia Nervosa and Atypical Anorexia Nervosa: Comparison of the Median BMI and Historical BMI Percentile

For adolescents with anorexia nervosa (AN), weight restoration is a key goal of treatment. Thus, determining an accurate estimated body (EBW) critical. In the past, researchers have used median BMI (mBMI) to determine patients’ EBW. However, wide range normal growth trajectories means that individual charts should be considered when patients atypical (AAN), using historical records may even more important. The primary objective this study was compare within-person differences between EBWs based on mBMI and historic (hBMI) percentile in AN AAN. secondary whether calculated from either method better predicted improvements two physiologic measures recovery: heart rate (HR) menstrual status. Participants included 209 aged 9-20 years old (M = 15.47, SD 2.21) (N 163, 78%) or AAN 46, 22%) completing treatment partial hospital program (PHP). Data were collected retrospectively at baseline discharge PHP. Paired sample t tests Person’s correlation for analysis. AN, EBW derived hBMI higher 53.60kg, 7.41) than 52.91kg 7.32), p .02. AAN, 58.35kg, 7.89) also 52.81kg, 6.20), <.001. magnitude difference larger (5.54kg) (0.69kg). When looking measures, upon entering PHP, HR correlated %hBMI (r .22) %mBMI .16), meaning increased as %EBW increased. At end remained .17), but not calculation time point. baseline, (both definitions) people who having regular periods (89% hBMI, 91% mBMI) those had amenorrhea (81% 82% mBMI). People %EBWs (95% 104% 97% Patients did meet definition malnutrition (<90% EBW) their (97% EBW), per EBW). Findings suggest percentiles are compared both though indicators by definitions AN. indicator while associated physiological signs. An likely marker recovery one mBMI, particularly