PWE-029 Characterisation and Association of Abdominal Pain With Anxiety or Depression in Patients with Irritable Bowel Syndrome with Constipation (IBS-C)

Abstract

Introduction: The Short-form McGill Pain Questionnaire (SF-MPQ-2) was developed to assess and characterize pain and is one of few instruments available for this purpose. The SF-MPQ-2 consists of 22 items (rated on a scale of 0=none to 10=worst possible), divided into 4 subscales: 3 are pain subscales (continuous, intermittent, neuropathic) using sensory descriptors (18 items); a fourth contains affective descriptors (4 items) of the emotional aspects of pain (such as describing pain as cruel or exhausting). The SF-MPQ-2 was validated in a variety of chronic pain syndromes, but not abdominal pain. Its use in functional gastrointestinal disorders, such as irritable bowel syndrome (IBS), is limited. Also, little is known about the qualities of pain in IBS. Aims: To use the SF-MPQ-2 to characterize baseline abdominal pain in IBS-C patients and determine whether the subscales are associated with significant baseline anxiety or depression. Methods: Patients meeting Rome II IBS-C criteria for IBS-C were enrolled in two Phase 3 trials of linaclotide. At baseline, 1523 patients rated their worst abdominal pain over the past 24 hours on a 0-10 point scale (0=none to 10=very severe) and completed the SF-MPQ-2. Summary statistics were calculated for each SF-MPQ-2 item and subscale. Patients were grouped by their highest-scored pain subscale; predominant pain type was defined as the group with the highest percentage of patients. The association of each subscale with baseline abdominal pain score was determined using an analysis of variance (ANOVA) model. The Hospital Anxiety and Depression Scale (HADS) assessed baseline anxiety (HADS-A) and depression (HADS-D) and patients were categorized as normal/borderline (0-10) or abnormal (11-21) for each. Logistic regression was used to determine whether each subscale was associated with abnormal HADS status. Results: The pain subscale type that was predominant was continuous pain (rated highest in 77% of patients) and the SF-MPQ-2 item in this subscale with the highest average score was cramping pain (Figure 1). Baseline abdominal pain score was most significantly associated with continuous pain (p<0.0001), followed by intermittent pain (p=0.004) and affective descriptors (p= 0.012), but was not significantly associated with neuropathic pain (p=0.526). Only the affective descriptors subscale was associated with abnormal HADS (HADS-A: p<0.0001, HADS-D: p<0.001; Table 1). Conclusions: Abdominal pain in IBS-C patients appears to be largely associated with continuous pain, and less so with intermittent and neuropathic pain. Cramping pain was rated as most intense on the McGill Pain Scale. The affective descriptors, but not the pain subscales, were significantly associated with baseline anxiety and depression, indicating that anxiety and depression are related to the emotional response to pain, not the pain itself. (Table presented) .