Bulimia Nervosa: Working Toward Better Definitions of Remission and Relapse

Relapse rates in bulimia nervosa (BN) range from 30% to 63%. The definition of remission in BN also is broad, spanning 2 to 8 weeks of abstinence from binge eating and purging. The least-stringent definitions of remission and relapse overlap, with 1 episode per week for 4 weeks qualifying as remission in some studies, but as relapse in others. Establishing a better definition of remission is particularly important because residual symptoms have been associated with an increased risk of relapse.

A study to better define remission and relapse in BN

In an attempt to better define remission and relapse in patients with BN, Marion Olmsted, PhD, Allan S. Kaplan, MD, and Wendi Rockert, MEd designed a study to compare the relapse rates obtained when definitions of remission and relapse were systematically varied (Int J Eat Disord 2005;38:1). In their uncontrolled, naturalistic, prospective follow-up study, 54 women were recruited one month after completing treatment and were asked to attend follow-up interviews every 3 months for up to 19 months. All the women had completed one of the treatment programs at the Toronto General Hospital Eating Disorders program and met Diagnostic and Statistical Manual of Mental Disorders, 3rd revision (DSM-IIIR) criteria for BN. All subjects weighed at least 85% of matched population mean weight.

In the last month of treatment, the women had a maximum of two episodes of binge eating and/or vomiting and one month later they had a maximum of 3 episodes of binge eating and vomiting. Thirty-three of the women had been treated in a day hospital program, 11 had received outpatient psychoeducational group treatment, 9 had undergone individual psychotherapy or pharmacotherapy, and 1 had been treated as an inpatient. Eight refused to attend the first follow-up interview, and the final study group included 46 women (mean duration of BN: 9.4 years).

At each follow-up visit, eating disorders symptoms were assessed and the women completed a calendar for each of the preceding 3 months, indicating significant social or vocational events and/or mood states to help them recall possible bulimic episodes. The researchers used four definitions of remission, 0, 1, 2, or 3 episodes of binge eating or vomiting in the month after the end of treatment.

Relapse rates depended on definitions

The relapse rates varied widely depending on the definitions for remission and relapse. By 19 months of follow-up, the lowest relapse rate, 21%, occurred among patients who were abstinent at baseline, with relapse defined as at least twice-weekly symptoms for 3 months. The highest relapse rate, 55%, occurred among patients who had the most symptoms at baselineup to 3 episodes–and those who had the least strict definition of relapse. At 19 months, relapse rates ranged from a low of 21% to a high of 55%. Adopting consistent definitions is a prerequisite to more informative and useful comparisons across studies, they reported. For example, the authors noted that in two previous retrospective studies they conducted on independent samples of patients, relapse rates were 29% and 31%. The comparable relapse rate is 40% in their current study.

Suggested definitions

The authors recommend that partial remission be defined as low-level symptoms (a maximum of 2 episodes per month) over a 2-month period, and that relapse be defined as meeting the full diagnostic criteria for BN (such as an average of 2 symptom episodes per week for 3 months), as described in the DSM-IV.

Dr. Olmsted and colleagues believe that future research could benefit from shared definitions of relapse and remission. Also, establishing such a reference point related to the primary behavioral criteria for BN might help clarify relapse, including quality of eating, weight-focused self-esteem, social functioning and the incidence of relapse from BN into other eating disorders.