Despite decades of research, anorexia nervosa remains, in many ways, a mysterious disorder. It is by all accounts an extremely serious illness, associated with a variety of medical complications and amongst the highest mortality rates of all psychiatric disorders. Fortunately, behaviorally-oriented treatments aimed at weight restoration, such as family-based therapy for adolescents or inpatient or residential programs, tend to be effective in renourishing and repairing the body, normalizing eating, and putting patients in the best position possible to work on the psychological elements of the disorder, such as fear of fat or body dissatisfaction.
For over four decades, our Columbia team has provided inpatient treatment to people interested in and eligible for our research studies. And over time, we have become convinced of the importance of understanding this illness in the context of longer-term outcomes and therefore curious about what happens when patients leave our program.
As is our way, we turned our curiosity into a series of scientific questions aimed at learning what predicts long-term outcomes following hospitalization for anorexia nervosa. We think that if we can identify factors associated with improved symptoms or sustained recovery, we might be able to find ways to enhance treatment and reduce the risk of relapse.
Since 2009, our group has conducted a longitudinal study designed to answer these very questions. Longitudinal research is important because it allows us to examine changes over the course of illness, and identify factors associated with this change. When we started this long term follow-up study, we planned to contact patients annually for 10 years. Recently, we’ve extended that to 20 years because the information that we are getting from participants is so very important to the field. In 2020, we were able to answer some initial questions about the first 5 years after hospitalization for anorexia nervosa.
Everyone on our inpatient unit is invited to participate in this long term follow-up study. Those who enroll provide information about weight and clinical symptoms at the end of treatment and annually for 10 years after discharge. At the end of the hospital stay, participants also complete questionnaires measuring eating disorder symptoms, mood and anxiety symptoms, anxious temperament, and general functioning. Each year following discharge, we contact participants to collect the same information, which we use to assess illness severity.
In our first paper from this rich dataset, we examined the first 5 years of follow-up information from 168 patients with anorexia nervosa and aimed to answer two primary questions: 1) what factors are associated with weight and general functioning over time? and 2) what factors are associated with maintaining healthy weight and better mental health?
What factors were associated with weight and general functioning over time?
Higher anxiety symptoms at the end of the hospital stay were associated with lower body mass index (BMI, a measure of weight standardized for height, calculated as weight in kilograms divided by height in meters squared) over time; however, scoring higher on anxious temperament was associated with higher BMI over the 5 years. Longer duration of illness was associated with losing weight more quickly.
In general, functioning improved over time (more specifically, impairment related to the eating disorder declined over time). However, longer duration of illness and more severe eating disorder symptoms at the end of inpatient treatment were associated with lower general functioning over the 5 years.
What factors are associated with maintaining health?
To answer this question, we identified individuals who maintained weight above the suggested minimum threshold for falling within a “healthy” weight range (according to the National Institutes of Health’s guidelines, BMI > 18.5 kg/m2), those who maintained above the recommended minimal cutoff for renourishment (BMI > 19.5 kg/m2), and those who maintained both a BMI > 18.5 kg/m2 and eating disorder symptom severity below the established scores for illness. The data showed that having a higher BMI at the time of admission to the hospital was associated with maintaining above the minimally “healthy” weight range cut-off over 5 years. Importantly, BMI at the time of leaving the hospital was also associated with maintaining health – it was related to maintaining above the 18.5 cutoff for minimally healthy weight and the 19.5 cutoff for renourishment. So, the ability to utilize the hospital treatment for full renourishment made a difference for health over the 5 years.
Individuals who maintained health according to both weight and symptom severity measures over the 5 years tended to have a shorter duration of illness and lower symptom severity scores when leaving the hospital.
So, what does all this tell us? Based on these data, there appear to be two important factors that contribute to better longer-term outcomes: a shorter duration of illness and higher weight. That is, individuals who received treatment earlier in the course of their illness and those who achieved greater weight gain during their inpatient stay reported better long-term outcomes.
These findings highlight the importance of early intervention and weight restoration for recovery from anorexia nervosa. For those who may be struggling with symptoms of an eating disorder, pursuing treatment as soon as possible can be critical for recovery. Regardless of when in the course of the illness an individual pursues treatment, gaining weight throughout treatment can improve chances of recovery in the long-term. Patients who are unable to reach their goal weight by the end of an inpatient stay may benefit from longer stays or structured step-down treatment until achieving weight restoration.
For those interested in learning more, our complete publication can be found here.
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