Introduction
Patients with irritable bowel syndrome (IBS) frequently report bothersome abdominal bloating and/or distention.
Aims & Methods
We aimed to investigate the association of these symptoms to overall symptom characteristics and gut sensorimotor function.
We included patients with IBS (Rome II-IV criteria) from studies investigating the association between IBS symptoms and pathophysiologic mechanisms. Validated questionnaires were used to evaluate gastrointestinal (GI) (GSRS-IBS and IBS-SSS), extraintestinal (PHQ-12), and psychological symptoms (HAD). Significant symptoms of abdominal bloating and/or distention were defined as a GSRS-IBS score ≥4 (at least moderate) for any of these two symptoms. Abdominal bloating or distention as the most bothersome symptom was defined in those scoring GSRS-IBS questions on bloating or distention higher than all other GI symptoms. Visceral sensory function was measured by a rectal barostat test and oro-anal transit time (OATT) was measured by use of radiopaque markers. Local reference values were used to define visceral hypersensitivity or abnormal OATT.
Results
We included 1100 patients with IBS; median age 35 (IQR 27-47) years and 794 (72%) females. IBS subtype distribution was IBS-C 30%, IBS-D 38%, and IBS-nonCnonD 32%.
Questions on abdominal bloating, abdominal distention, and passing gas had the highest median score, 5 (moderately severe), of all GSRS-IBS items (IQR 4-6 for bloating and passing gas, IQR 3-6 for distention). Significant abdominal bloating and/or distention was reported by 91.6% and 81.2% respectively, with a female predominance (74% and 78% respectively) and were equally distributed across IBS-subtypes (p=0.09). Having significant symptoms of abdominal bloating or distention was associated with more extraintestinal symptoms (PHQ-12) and more severe IBS symptoms (IBS-SSS) (p<0.001 for both). In addition, significant abdominal bloating was also associated with increased psychological symptoms (HAD), while significant distention was not (p<0.05 and p=0,22 respectively). There was no association between having significant abdominal bloating/distention and abnormal OATT or visceral hypersensitivity (Table 1).
Abdominal distention was more common as the most bothersome symptom compared to abdominal bloating (13% vs. 5%), both with a female predominance (76% and 79% respectively). The severity of IBS, extraintestinal, and psychological symptoms were similar in patients with and without abdominal bloating or distention as the most bothersome GI symptom (p=0.09, 0.45, and 0.76 for bloating and p=0.21, 0.13, and 0.69 for distention). However, abdominal bloating as the most bothersome GI symptom was associated with delayed OATT and visceral hypersensitivity. No such difference was noted comparing those with and without abdominal distention as the most bothersome GI symptom. Table 1.
| Significant bloating | Not significant bloating | p-value | Bloating most bothersome symptom | Bloating not most bothersome symptom | p-value | Significant distention | Not significant distention | p-value | Distention most bothersome symptom | Distention not most bothersome symptom | p-value |
Delayed OATT n (%)
| 35 (8) | 3 (4.6) | 0.24 | 5 (25) | 33 (6.8) | 0.01 | 27 (7) | 11 (9.2) | 0.26 | 4 (8) | 34 (7.5) | 0.95 |
| Normal OATT n (%) | 300 (68.5) | 41 (63.1) | 13 (65) | 328 (68) | 267 (69.7) | 74 (61.7) | 34 (68) | 307 (67.8) |
| Accelerated OATT n (%) | 96 (28.6) | 21 (32.3) | 2 (10) | 122 (25.3) | 89 (23.2) | 35 (29.2) | 12 (24) | 112 (24.7) |
| Visceral hypersensitivity n (%) | 96 (28.6) | 4 (13.8) | 0.09 | 88 (25.6) | 88 (25.6) | 0.016 | 70 (25.7) | 29 (31.5) | 0.28 | 11 (29.3) | 88 (27.7) | 0.59 |
Conclusion
The presence of significant bloating or distention in IBS is common and associated to more severe IBS as well as increased symptom burden, regardless of it being the most bothersome symptom or not, while the presence of bothersome abdominal bloating is associated to a deviant gut sensorimotor function. Our results suggest that bloating and distention play an important role in both disease burden and in further understanding pathophysiological mechanisms in IBS.
Disclosure
No conflicts of interest to declare
