Patient Dissatisfaction with Medical Therapy for Chronic Constipation or Irritable Bowel Syndrome with Constipation: Analysis of N-of-1 Prospective Trials in 81 Patients

Background: Patients with chronic constipation (CC) or with irritable bowel syndrome with constipation are often dissatisfied about their medical therapy, but their condition remains poorly defined.

Aim: To evaluate the patients' satisfaction rates and which factors predict favourable outcomes through the aggregate analysis of N-of-1 trials.

Methods: Eighty-one outpatients with CC or with irritable bowel syndrome with constipation underwent N-of-1 trials with at least a one-month cycle of effective treatment. Three primary endpoints (satisfaction with therapy, improvement after treatment and an extended satisfaction criterion including both endpoints) were adopted to define satisfaction with therapy. Dyssynergia, resting anal pressure, colonic transit time and somatisation were assessed. The Patient Assessment of Constipation-Symptoms (PAC-SYM) questionnaire and its Modified version (M-PAC-SYM) measured constipation severity. Straining at defecation, stool frequency and form were daily recorded. K statistics for agreement and logistic regression were used at statistical analysis.

Results: Satisfaction with therapy was not achieved by 43% of patients, who had a significantly lower Body Mass Index (BMI) and more severe constipation at baseline. Only the change in constipation severity according to M-PAC-SYM remained significantly associated with satisfaction with therapy (OR = 4.3; P < 0.001) at multivariate analysis.

Conclusions: Satisfaction with therapy is often an unmet need for patients with CC or with irritable bowel syndrome with constipation. Lower BMI and more severe constipation are associated with worse outcome. Changes in M-PAC-SYM reflect satisfaction with therapy. ClinicalTrials.gov no. NCT02813616.