Persuading patients with BN to enter treatment trials is much easier than persuading those with AN, according to Halmi. Patients with BN tend to enter trials and stay three or four months.
More than 30 placebo-controlled, randomly assigned drug studies have shown all antidepressants to be effective in reducing binge-eating/purging behavior, Halmi said.
"However, they only produce complete abstinence of binge/purge behavior in 20% to 30% of the bulimic population," she added. (For further discussion of 19 trials of antidepressants versus placebo for individuals with BN, see Bacaltchuk and Hay --Ed.)
More than 20 randomly assigned, controlled studies have shown CBT to be effective in reducing binge/purge behavior in 90% of patients with BN and producing abstinence from such behavior in about 30% to 40%.
Currently, the first line of treatment for BN is CBT, Halmi said, since after 20 weeks of treatment more patients stayed abstinent from their binge/purge behavior with CBT than those who were on medication alone.
More effective therapies need to be developed for AN and BN, Halmi emphasized. One potential new treatment for BN may be topiramate(Drug information on topiramate) (Topamax), she said. Hoopes et al. (2003) conducted a randomized, double-blind, placebo-controlled trial to assess the efficacy and safety of topiramate in BN. The researchers concluded that topiramate was associated with significant improvements in both binge and purge symptoms in the study population.
Looking at relapse issues, Halmi described a treatment study of patients with BN who had received CBT (Halmi et al., 2002). This multisite study examined relapse in 48 patients with BN who had responded to CBT with complete abstinence from binge-eating and purging. Structured interviews and questionnaires were used to assess patients before and after treatment and at four months after treatment. At four months posttreatment, 44% had relapsed. Characteristics of those who relapsed included shorter duration of illness, fewer weeks of abstinence during treatment, a higher rating on severity of eating disorders at the end of treatment, less motivation for change and lower self-esteem.
Economic factors impacting relapse rates, according to Halmi, are the limits imposed by managed care organizations on hospital length-of-stays for patients with eating disorders. Studies from Australia and the University of Iowa analyzing patients' body mass index (BMI) at discharge from inpatient treatment found that patients discharged with a BMI <19 had a significantly greater risk of relapse compared with those who had a BMI ≥19. At the Weill Cornell program, Halmi said, the median discharge BMI from inpatient treatment fell from 19.5 in the 1980s to 17.5 in 1999. Meanwhile, the mean length of stay dropped from an average of 140 days in the early 1980s to 23 days in 1999.