The subjects were women between the ages of 18 and 45 years recruited from two studies: the Fluoxetine for Relapse Prevention in Women With Anorexia Nervosa trial (New York site only, reference 7
) and Energy Homeostasis in Anorexia Nervosa, a longitudinal study involving the examination of changes in body composition (8
). Thirty-two of the 45 relapse-prevention trial participants also participated in the body composition study. Reasons for nonparticipation in the body composition study included being less than 18 years old (N=5), taking psychotropic medications or medications known to affect body composition (N=2), the presence of a comorbid diagnosis of substance abuse (N=2), and the presence of nonremovable metal (N=1). In addition, two women participated in the relapse-prevention study before the initiation of the study of body composition, and one woman declined to participate. The subjects were free from medications for a minimum of 2 weeks (4 weeks for oral contraceptives) before testing.
After complete description of the studies to the subjects, written informed consent was obtained. These studies were approved by the institutional review boards of the New York State Psychiatric Institute, Columbia University, and St. Luke’s–Roosevelt Hospital Center.
The subjects received inpatient treatment sufficient to normalize weight to at least 90% ideal body weight and were studied after maintaining ≥90% ideal body weight for 2–4 weeks (8
) but before random assignment in the relapse-prevention trial. Menstruating subjects were tested during the follicular phase of the cycle.
Testing included fasting, morning blood sampling, and body composition assessment. Anthropometry and dual-energy X-ray absorptiometry for body composition measurement were performed at the Body Composition Unit of the New York Obesity Research Center at St. Luke’s–Roosevelt Hospital Center.
The patients were assessed wearing a hospital gown and underwear. They were informed that measurements were for research purposes only and would not affect their clinical treatment. Height was measured using a wall-mounted stadiometer to the nearest millimeter. Weight was measured to the nearest 0.1 kg with a calibrated physician’s office scale. Using a standard cloth tape measure, waist circumference was measured in millimeters at the level immediately below the lowest ribs, and hip circumference was measured below the iliac crest. Two trained assessors performed all assessments. The intraobserver coefficient of variation was 1.0%. The waist-to-hip ratio was calculated as the quotient of the waist circumference divided by the hip circumference. Total body dual-energy X-ray absorptiometry was performed (DPX-L, GE Lunar, Madison, Wis.) to obtain percent body fat.
Cortisol was measured with solid-phase, chemiluminescent immunoassays (Immulite, Diagnostic Products Company, Los Angeles). Assay sensitivity was 0.2 µg/dl. Intra- and intercoefficients of variation were 7.6% and 10.2%, respectively.
Leptin was measured with a commercial immunoradiometric assay kit (Diagnostic Systems Labs, Inc., Webster, Tex.). Assay tubes were incubated overnight at room temperature. Assay sensitivity was 0.25 ng/ml. Intra- and interassay coefficients of variation were 2.5% and 3.6%, respectively.
Although survival analysis was the primary analysis used in the Walsh et al. (7
) trial, subject outcome at study termination was also classified using the modified Morgan-Russell criteria (full, good, fair, or poor) (9
). The subjects were classified as “other” when they did not meet the time criteria (remaining in the study for at least 8 weeks) for Morgan-Russell determination (7
). Outcome was dichotomized into “treatment success,” defined as a Morgan-Russell categorization of full, good, or fair, and “treatment failure,” defined as a Morgan-Russell categorization of poor. Consistent with the Morgan-Russell classification, we excluded six subjects whose outcome was categorized as “other”; thus, data from 26 subjects were available for analysis. Including subjects with an “other” outcome in the “treatment failure” group did not significantly change the results of the study.
Clinical variables were compared between those in the “treatment success” and “treatment failure” groups by using Student’s t test. Logistic regression models were constructed to evaluate the effects of body mass index, percent body fat, subtype, waist-to-hip ratio, and serum cortisol and serum leptin levels on treatment outcome. Because no significant effect of fluoxetine was found on preventing relapse (7
), medication assignment was not considered as a covariate in these analyses.
Lifetime highest body mass index was obtained by self-report, and percent of lifetime highest body mass index at testing was calculated as (body mass index/lifetime highest body mass index) * 100.
Analyses were performed with SPSS for Windows (version 10.1, SPSS, Chicago). Means and SDs are reported; t tests were two-tailed. Significance level was set at 0.05.