Changes and predictive value for treatment outcome of the compulsive exercise test (CET) during a family-based intervention for adolescents eating disorders

Participants

The Eating Disorders Unit (EDU) at The Department of Child and Adolescent Psychiatry of the Uppsala University Hospital is the only specialised ED unit in the county. It provides treatment to all patients with ED and < 18 years of age in the county (population 345,481 of which 70,424 < 18 years on Dec 31 2013) [16]. During the period March 2012 – June 2016 297 new patients were assessed and diagnosed with a restrictive ED. Two hundred and seventy-seven started treatment at the EDU. One year after presentation (12,4 ± 0,8 months, range 10–15) 198 (71%) of these attended a follow-up interview. Complete data including growth charts with premorbid weight, weight at presentation and at follow-up, and all the self-report instruments were available for 170 (61%). This a secondary analysis of the data since the sample partly overlaps with that of a previous analysis of predictors of outcome in our treatment programme [17].

Procedure

Assessment of new patients was performed by a paediatrician with experience of ED. An interview with the adolescent and at least one parent included the history of the ED, and a general medical history to assess somatic and psychiatric comorbidity. Weight and height were measured in underwear only, and a physical examination performed. Blood samples were obtained to exclude hitherto unknown comorbid disease and to evaluate the impact of weight loss on metabolism and nutritional state. Growth charts were procured from the school health services for objective measures of premorbid growth and weight changes. An ED diagnosis was established, and treatment immediately started (see below). A second appointment was scheduled 1 week later. At this meeting assessment was reviewed and instruments administered. Measurements of weight and length were registered at 1 week, 1 month and 3 months after start of treatment. One year after start of treatment a face-to-face follow-up interview was performed, usually by the therapist who had seen the patient/family for the past year. This was to map ED ideation and ED behaviours such as restricting food, vomiting or exercising for weight control and determine whether the adolescents fulfilled criteria for an ED. The follow-up visits included measurement of weight and length and administration of the self-report questionnaires used at presentation. The procedure for assessment, start of treatment and follow-up has been described in detail [17, 18].

The protocol was approved by the Ethics Committee of the Faculty of Medicine of Uppsala University.

Study measures

ED diagnoses were according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth edition (DSM-5). The earliest part of the sample had been diagnosed according to DSM-IV and was retrospectively recoded into DSM-5 criteria. Body mass index (BMI) was calculated as weight/height² (kg/m²) and recalculated into BMI standard deviation scores (BMI SDS), which constitutes a measure of leanness corrected for age and height [19]. BMI SDS below − 2.00 was used as the weight criterion for anorexia nervosa (AN) [16, 20]. At presentation weight loss was calculated as the difference between weight at presentation and the highest recorded premorbid weight. At follow-up weight suppression was calculated as the difference between BMI SDS at follow-up and BMI SDS at the highest premorbid weight.

A recently validated Swedish version [14] of the CET [12] was used. The CET is comprised of five subscales with altogether 24 items which assess cognitive and behavioural aspects of compulsive exercise. Responses are scored from zero to five and averaged for each subscale with high scores representing a high degree of compulsive exercise. The subscale “avoidance and rule-driven behaviour” (e.g., “If I cannot exercise I feel low and depressed”) taps regulation of low mood by exercise. “Weight control exercise” (e.g., “I exercise to burn calories and lose weight”) is related to modification of weight and shape by exercise. “Mood improvement” (e.g., “Exercise improves my mood”) is associated with enhancing good mood. “Lack of exercise enjoyment” (e.g., “I do not enjoy exercising”) and “exercise rigidity” (e.g., “I follow a set routine for my exercise sessions”) is related to obsessional and rigid aspects of exercise. To the CET was added a question on exercise frequency: “How many days per week do you usually exercise?”

The Eating Disorders Examination-Questionnaire youth version (EDE-Q) [21] was used to assess ED ideation. Twenty-three items are subdivided in the four subscales “eating restraint”, “eating concern”, “weight concern” and “shape concern”. Items are scored from zero to six and averaged for each subscale with high scores representing a high degree of ED ideation. A global score is calculated by averaging the subscale scores. The Montgomery-Åsberg Depression Rating Scale-Self report (MADRS-S) [22] was used to assess depressive symptoms. Nine items are scored from zero to six and summed with high scores representing high depressive symptomatology.

Recovery was defined by two separate measures: 1) EDE-Q global score < 2.0. This cut-off corresponds to the mean + 1 SD of the score of adolescent reference samples [21, 23] and to the clinically significant score in a Swedish sample [24]. 2) Not meeting diagnostic criteria for an ED at the interview at the one-year follow-up.

Treatment

Treatment is family based and underscores the role of the parents in the care of their child. In Sweden this is supported by the social security system which allows reimbursed parental leave to care for a sick child under the age of 18. Treatment is an outpatient intervention, which can be intensified by adding day treatment [16]. In-patient treatment is not part of the treatment programme and used only in emergency situations [25].

The first step of the treatment programme has an aim of stopping on-going weight loss and bringing meal routines back into order. This is underscored already at presentation [18]. Parents get advice on their role in the re-establishment of their family meal practices. They are advised as to what is a normal-size meal and to implement normal table manners. Routines for avoiding vomiting after meals are suggested. Attending school is advised against as long as meal pattern and normal eating have not been re-established. All forms of exercise are stopped at the start of treatment.

The second step of the programme follows when meal routines have been re-established although support at all meals is necessary. The aim is now to restore weight by 0.5–1 kg/week. A final step starts with a gradual reintroduction into school. This requires that eating has been normalised and that weight deficit has decreased considerably. Vigilance over daily routines can be reduced although meal support may still be needed. Exercise is reintroduced, usually what the adolescent took part in before falling ill, provided that it can be done safely without recurrence of ED cognitions. The possibility of co-morbid psychiatric disease may now be reassessed and treatment of problems outside the core features of the ED introduced. For example, low self-esteem, over-evaluation of weight and shape, perfectionism and/or interpersonal difficulties can be addressed to prevent relapse. The programme does not have a fixed number of sessions, but the steps are goal oriented. Duration of treatment varies with a median of ten sessions (range 4–36) over a median of 9 months (range 3–24). At the one-year follow-up approximately 50% of the patients have finished treatment, 35% are still in treatment at the EDU and 15% have been referred to other psychiatric services or has discontinued treatment against advice. At follow-up patients have, with few exceptions, been reintroduced into exercise. The treatment programme has previously been described in detail [16–18].

The treatment programme is strongly influenced by FBT [26]. It differs in that parents are suggested interventions at the first session rather than empowering them to find their own solutions to re-establish meal routines. It also differs in that cognitive behavioural therapy is used for comorbid disorders and remaining ED-related issues. The important similarity with FBT is the emphasis on that it is the parents who should take a leading role against the ED and re-establish family routines.

Data analysis

Statistical analyses were performed in SPSS 20.0.0. Values are given as means ± SD. Differences in weight and psychometrics measures were compared using Student’s t-test for independent samples for continuous data and Chi-square tests for categorical data. To minimize the risk for mass significance and type 1 error the significance level was set at p < 0.01. To analyse predictors of outcome logistic regression analyses were used. In these analyses either one of the outcome measures “EDE-Q global score <2.0” or “no ED at the follow-up interview” was entered as the dependent variable. In a first set of analyses each of the different CET subscales was entered as an independent variable to determine whether any one was related to outcome prior to correction for the other predictors. In a second set of analyses BMI SDS at presentation, EDE-Q global score at presentation, weight gain at 3 months and weight suppression at follow-up were entered together as independent variables since they have previously been shown to predict outcome [17]. The individual CET subscales were then forced into the models to asses if they independently added to and predicted outcome.

Patient characteristics

Chronic somatic diseases were present in 20 (12%) patients; of these five had type 1 diabetes, five had coeliac disease and two had hypothyreosis. Psychiatric comorbidity, other than depression, and in all but one neuropsychiatric diseases, was present in 12 (7%). None of the comorbid diagnoses was judged to influence the ability to exercise.

Patient characteristics in relation to outcome

At the one-year follow-up recovered patients had greater weight gain, less weight suppression, and a lower prevalence of depression. On the CET they had, in comparison with non-recovered, considerably lower scores on the “avoidance and rule driven behaviour”, “weight control exercise” and “exercise rigidity” subscales while “mood regulation” was only little lower. Patients who were not recovered had CET scores at the level observed at presentation.

Of the patients meeting the EDE-Q criterion for recovery twenty-six (21%) were not considered recovered at the one-year follow-up interview. Ninety-nine (58%) patients did not fulfil diagnostic criteria for an ED at the follow-up (Table 2). At presentation, they did not differ from those not recovered. Weight gain during the first 3 months of treatment was greater for recovered patients. At the follow-up they had greater weight gain and a lower prevalence of depression. On the CET recovered patients, in comparison with non-recovered, had considerably lower scores on the “avoidance and rule driven behaviour” and “weight control exercise” subscales while “exercise rigidity” was only little lower and “mood regulation” and “lack of exercise enjoyment” did not differ. Patients who were not recovered had CET scores at the level observed at presentation.

Predictors of outcome