The treatment variables that affect long-term recovery
The basic goals of eating disorder treatment are to reduce or eliminate ED symptoms, address co-morbid disorders, and improve quality of life. When researchers study these treatment in clinical trials, they generally focus on the first issue and seek to ask whether this treatment reduces ED symptoms. It’s not a bad goal for an ED treatment, though hardly comprehensive.
Still, the assessment of whether a certain treatment leads to short- or long-term recovery is much thornier. First, there’s the fact that there’s no standard definition of what constitutes recovery (I’ve blogged about this here, here, here, and here). Second, there’s no understanding of what should be targeted during treatment to improve chances of recovery. In other words, what factors predict recovery during ED treatment?
In a new study in the International Journal of Eating Disorders, researchers took on that task (Lock et al, 2013) and used outcome data from a variety of randomized control trials for different EDs to identify some of the factors that emerged as the most important to target during treatment. The researchers also questioned the utility of a common transdiagnostic model for ED recovery.
What the study did
The researchers used a total of 358 females who had received treatment in one of five RCTs for eating disorders: adult AN, BN, and BED, and adolescent AN and BN. The trials all used different treatments, so the goal of the study was not to find treatment-specific outcomes but to identify what any type of treatment should be targeting. Some of the details are below:
The researchers used Anna Bardone-Cone’s defintion of recovery (Bardone-Cone et al., 2010):
These authors operationalized their definition of full recovery as follows: (1) no longer meeting diagnostic criteria for an eating disorder (AN, BN, or EDNOS); (2) no binge eating, purging (e.g., vomiting and laxative use), or fasting in the past 3 months; (3) a body mass index (BMI) of at least 18.5 kg/m2 (a BMI of 18.5–24.9 is considered normal by the World Health Organization); and (4) scores within 1 SD of age-matched community norms on all the subscales of the EDE-Q.
Going along with this, Lock et al. focused on three areas of recovery: behavioral, psychological, and physical. They created a mathematical model to predict which of the outcome measures identified at the end of treatment made someone more likely to meet Bardone-Cone et al‘s definition of recovery at follow-up. Only in adolescents with BN did the researchers identify more than one predictor of recovery. Here’s a list of what they found:
- In adults with AN, so few met any of the recovery criteria that they had to relax these criteria to identify predictors: Ideal Body weight >85.75% at the end of treatment, and EDE scores of weight concern <1.8
- In adolescents with AN, the people most likely to meet recovery criteria at the end of follow-up had an IBW >95.2%
- In adults with BN, reduction of purging and other compensatory behaviors to less than twice per month
- In adolescents with BN, elimination of compensatory behaviors and a reduction of the EDE restraint score by more than 3.4 between start and end of treatment
- In adults with BED, binge eating episodes per se did NOT predict recovery. Instead, a reduction in global EDE scores to less than 1.58 were most predictive of recovery
Given that more than one predictor was present only rarely in these, the authors say that it means a transdiagnostic definition of recovery is probably less useful than those that are more disorder-specific. Which, as much as Bardone-Cone’s model of ED recovery is a good theoretical construct, the variation of symptoms and concerns in the different EDs probably means that it’s less useful on a practical level.
What’s more, the factors that predict ongoing recovery are going to be different for different disorders. Which makes a lot of sense since treatment targets different factors in different disorders. I’ve never been a big fan of the transdiagnostic model for EDs, given that I don’t think body image concerns are inherently central to the disorder, nor does the genetic evidence indicate that this is the case. Certainly there is plenty of overlap between the disorders, and specific diagnoses tend to be more transient than not, but these results further emphasize that each ED has distinct characteristics that must be specifically addressed in treatment.
The study does have significant limitations: for one, the number of people involved is relatively small. For another, there was a huge number of treatment protocols used, which makes it much harder to compare the different groups. As well, these were research trials not treatment received in the community, which could be very different. These conclusions are pretty tentative, but it was a good test of the transdiagnostic model and yet another reason the ED research community needs to develop a more rigorous and useful definition of ED recovery for use in research.
Conclude the authors:
This study highlights some of the challenges inherent in developing and understanding the meaning of recovery for eating disorders. Nonetheless, in our view the importance of making progress in better defining recovery in eating disorders cannot be overstated. As with other disorders and diseases, common benchmarks that inform patients, clinicians, and researchers about progress and outcome are necessary. We need to speak a common language and share common goals to make significant progress in understanding and treating eating disorders. However, current data suggest in the field of eating disorders we still need to consider the stage of illness and specific diagnoses of patients when considering the definition of recovery.
Lock, J., Agras, W. S., Grange, D., Couturier, J., Safer, D., & Bryson, S. W. (2013). Do end of treatment assessments predict outcome at follow‐up in eating disorders?. International Journal of Eating Disorders. DOI: 10.1002/eat.22175
Bardone-Cone, A. M., Harney, M. B., Maldonado, C. R., Lawson, M. A., Robinson, D. P., Smith, R., & Tosh, A. (2010). Defining recovery from an eating disorder: Conceptualization, validation, and examination of psychosocial functioning and psychiatric comorbidity. Behaviour research and therapy, 48(3), 194-202. DOI: 10.1016/j.brat.2009.11.001