Defecatory disorders in anorexia nervosa: a clinical study

Background

Defecatory disorders in patients with eating disorders have been overlooked. We evaluated the prevalence and type of defecatory disorders in patients with anorexia nervosa.

Methods

The aim of our questionnaire-based study was to determine the prevalence of constipation and faecal incontinence (FI) in patients with anorexia nervosa attending our dedicated eating disorders outpatient clinics and whether length of illness and low body mass index (BMI) exacerbate both constipation and FI. The Wexner constipation score (WCS), Altomare’s obstructed defecation score (OD score) and the faecal incontinence severity index (FISI) were used to evaluate constipation and incontinence. A WCS ≥5, OD score ≥10 and a FISI ≥10 were considered clinically relevant.

Results

Eighty-five patients (83 females; mean age 28 years ± 13) with anorexia nervosa (study group) and mean BMI of 16 ± 2 kg/m² (range 14–19 kg/m²) were studied. This group was compared to 57 healthy volunteers (control group) with mean BMI of 22 ± 3 kg/m² (range 20–27 kg/m²). In the study group, 79/85 (93 %) patients suffered from defecatory disorders defined as at least one abnormal score, either WCS, OD score or FISI, compared to 7/57 (12 %) controls (p < 0.001). Constipation (defined as WCS ≥5) was present in 70/85 (83 %) patients with anorexia and in 7/57 (12 %) controls (p = 0.001), while obstructed defecation syndrome (defined as OD score ≥10) was present in 71/85 (84 %) patients with anorexia and 7/57 (12 %) controls (p < 0.001). In patients with anorexia, the mean WCS score was 10 ± 5 standard deviation (SD) (3 ± 2 SD in controls; p < 0.001), and the mean OD score was 12 ± 4 SD (3 ± 4 SD in controls; p < 0.001). Overall, 62/85 (73 %) patients with anorexia had FI defined as FISI score ≥10, and the mean FISI score in anorexia patients was 12 ± 9 SD. A combination of constipation and FI (either both WCS and FISI abnormal or both OD score and FISI abnormal) was present in 55/85 (64 %) and 8/85 (9 %) presented with FI alone. Moreover, all results are influenced by the severity of the disease measured by BMI and duration. The percentage of defecatory disorders rises from 75 to 100 % when BMI is <18 kg/m² and from 60 to 75 % when the duration of illness is ≥5 years (p < 0.001 and p = 0.021, respectively).

Conclusions

Defecatory disorders are associated with anorexia nervosa and increased with the duration and severity of the illness.