Treatment goal weight in adolescents with anorexia nervosa: use of BMI percentiles.

OBJECTIVE

There is a lack of consensus as to how to determine treatment goal weight in the growing adolescent with anorexia nervosa (AN). Resumption of menses (ROM) is an indicator of biological health and weight at ROM can be used as a treatment goal weight. This study determined the BMI percentile for age at which ROM occurs.

METHOD

A secondary analysis of a prospective cohort study examining 56 adolescent females with AN, aged 12-19 years, followed every 3 months until ROM. BMI percentiles for age and gender at ROM were determined using the nutrition module of Epi Info 2002.

RESULTS

At 1-year follow-up, 36 participants (64.3%) resumed menses and 20 (35.7%) remained amenorrheic. Mean BMI percentile at ROM was 27.1 (95% CI = 20.0-34.2). Fifty percent of participants who resumed menses, did so at a BMI percentile between the 14th and 39th percentile.

CONCLUSION

A BMI percentile range of 14th-39th percentile can be used to assign a treatment goal weight, with adjustments for prior weight, stage of pubertal development, and anticipated growth.