Similarities in Clinical and Psychosocial Characteristics of Functional Diarrhea and Irritable Bowel Syndrome With Diarrhea

Abstract

There have been few published studies of clinical and psychological characteristics of patients with functional diarrhea (FDr). We studied the clinical and psychological characteristics of patients with FDr presenting to a tertiary care clinic, and compared symptom profiles of FDr with those of IBS-diarrhea (IBS-D). Consecutive patients with a diagnosis of FDr (n= 48) or IBS-D (n= 49), per Rome IV criteria, completed a detailed symptom survey from October 2017 through July 2018. Abdominal pain and diarrhea severity were assessed using patient-reported outcomes measurement information system (PROMIS) questionnaires. Patients with anxiety, depression, or sleep disturbances were identified based on PROMIS T-score of 60 or more. Mean and proportions were compared using the Student t test and chi-square analyses, respectively. A significantly lower proportion of patients with FDr reported abdominal pain (77.1%) than patients with IBS-D (100%, P < .001). The proportion of patients reporting abdominal bloating and level of severity did not differ significantly between groups. Proportions of bowel movements with diarrhea did not differ significantly between groups (P= .54), but the mean diarrhea PROMIS T-score was significantly higher among patients with IBS-D (P= .03). This difference resulted from the significantly higher levels of fecal urgency-related distress reported by patients with IBS-D (P= .007). Proportions of patients with anxiety, depression, or sleep disturbance, and their severities, did not differ significantly between groups. In an analysis of about 100 patients with FDr or IBS-D, we found overlap in gastrointestinal and psychosomatic symptoms. These 2 entities appear to be a continuum.