Comorbidity of diabetes mellitus and eating disorders: a follow-up study.

Objective: There is increasing evidence that the coexistence of diabetes and eating disorders (ED) leads to poor glycemic control and an increased risk of long-term complications.

Methods: In a questionnaire- and interview-based study, a sample of 36 out of originally 38 (94.7%) diabetic patients with an ED (type-1: n=13, type-2: n=23) was assessed after a period of about 2 years in order to determine the course of EDs, body mass index (BMI), glycemic control, and psychiatric symptomatology.

Results: Five patients (13.9%) of the total sample showed full remission for at least 12 consecutive weeks. Twenty-two patients (61.6%) showed no change in the diagnosis of the ED. Four patients (11.1%) shifted from subclinical to clinical EDs and five patients (13.9%) vice versa. Of the eight patients who went on to psychotherapy, only one patient (12.5%) showed full remission. Emotional distress of type-2 diabetics was considerably higher compared to type-1 diabetics, which was rather low at baseline. Except interpersonal distrust as one ED-related variable, no significant change of any psychological variable could be observed in the type-1 diabetic sample during follow-up. Of the 13 type-1 diabetic patients with an ED, five patients deliberately omitted insulin in order to lose weight. These patients showed a more serious psychopathology with regard to each measured psychological variable, a higher BMI, and worse metabolic control compared to those without insulin omission. Type-2 diabetics showed a significant increase in drive for thinness and body dissatisfaction. No considerable change could be observed with regard to BMI, glycemic control, and depressive and global psychiatric symptomatology in either diabetic subsample during follow-up.

Conclusion: EDs tended to persist over time with a considerable shift within the different types of EDs. Insulin-purging in type-1 diabetics was associated with enhanced psychopathology, higher BMI, and worse metabolic control. Both mean body mass and ED-related symptoms such as "drive for thinness" and "body dissatisfaction" increased in the average obese type-2 diabetic sample, illustrating the vicious circle of low self-esteem, enhanced restraint eating, and binge eating in weight control measures.