Characteristics of, and natural history among, individuals with Rome IV functional bowel disorders

The Disease Spectrum and Natural History of Patients With Abdominal Bloating or Distension: A Longitudinal Study

Background/Aims

Abdominal bloating or distension (AB/D) is a common complaint in the outpatient of gastroenterology department. Since the potential contributors are numerous and complex, a longitudinal study on the disease spectrum and natural history of patients was performed to better understand the key factors of AB/D.

Methods

Consecutive patients with the chief complaint of AB/D referred to the outpatient clinic were screened. Functional gastrointestinal disorders (FGIDs) were diagnosed according to Rome IV criteria. A 3-year follow-up was performed to seek for the changes in symptoms as well as disease spectrum.

Results

A total of 261 participants were enrolled and 139 completed the follow-up. Most patients suffered from moderate to severe symptoms more than 1 day per week. Common causes of AB/D were FGIDs (51.7%) and organic diseases (17.2%). The latter group was older with lower body mass index (BMI). Functional dyspepsia was the most common type of FGIDs in AB/D. The symptoms of 18.0% of participants failed to improve at the end of the 3-year follow-up, and those diagnosed with FGIDs were most likely to continue to suffer. Abdominal pain was a positive predictive factor for good prognosis in the FGIDs group. Besides, only 22.7% of participants had a consistent diagnosis of FGIDs during follow-up.

Conclusions

FGIDs are the most common diagnosis in patients with AB/D. Symptoms were especially hard to be improved. Classification diagnoses of FGIDs in AB/D patients fluctuated significantly over time.

What Is Unspecified Functional Bowel Disorder? A Commonly Seen, Rarely Recognized, and Poorly Understood Diagnosis

INTRODUCTION

Unspecified functional bowel disorder (FBD-U) is a Rome IV diagnosis of exclusion and occurs when patients report bowel symptoms but do not meet the criteria for other functional bowel disorders (FBD; irritable bowel syndrome [IBS], functional constipation [FC], functional diarrhea [FDr], or functional bloating). Previous research suggests that FBD-U is as/more common than IBS.

METHODS

One thousand five hundred one patients at a single-center tertiary care center completed an electronic survey. Study questionnaires included Rome IV Diagnostic Questionnaires, anxiety, depression, sleep, health care utilization, and bowel symptom severity measures.

RESULTS

Eight hundred thirteen patients met Rome IV criteria for a FBD and 194 patients (13.1%) met criteria for FBD-U, representing the second most common FBD after IBS. Severity of abdominal pain, constipation, and diarrhea were lower in FBD-U compared with other FBD, whereas health care utilization was similar among the groups. Scores on measures of anxiety, depression, and sleep disturbances were similar in FBD-U compared with FC and FDr but were less severe than IBS. Between 25% and 50% of patients with FBD-U did not meet Rome IV criteria for other FBD due to timing of onset of the target symptom (e.g., constipation for FC, diarrhea for FDr, and abdominal pain for IBS).

DISCUSSION

FBD-U, by Rome IV criteria, is highly prevalent in clinical settings. These patients are not represented in mechanistic studies or clinical trials for not having met Rome IV criteria for other FBD. Making future Rome criteria less stringent would minimize the number fulfilling criteria for FBD-U and maximize the true representation of FBD in clinical trials.