Neurogastroenterol Motil. 2022 Dec 26;e14515. doi: 10.1111/nmo.14515. Online ahead of print.

Christopher Roberts ^1 2, Ahmed Albusoda ¹, Adam D Farmer ^1 3 4 5, Qasim Aziz ¹

Author information

¹Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Wingate Institute of Neurogastroenterology, Barts and the London School of Medicine & Dentistry, Queen Mary University of London, London, UK.

²Department of Paediatric Gastroenterology, University Hospital Southampton, Southampton, UK.

³Mech-Sense, Department of Gastroenterology, Aalborg University Hospital, Aalborg, Denmark.

⁴Institute of Applied Clinical Sciences, University of Keele, Keele, UK.

⁵Department of Gastroenterology, University Hospitals of North Midlands NHS Trust, Stoke on Trent, UK.

Abstract

Background: A frequent, although not universal, feature of irritable bowel syndrome (IBS) is heightened sensitivity to mechanical stimulation of the rectum, termed rectal hypersensitivity (RH). Differences in RH-based on sex, IBS subtype, IBS diagnostic criteria and age of population studied are incompletely understood. We aimed to determine whether IBS population had lower pain thresholds than healthy controls.

Methods: We searched MEDLINE and EMBASE databases (1970-2021). Prospective studies that compared pain/discomfort thresholds to mechanical rectal stimuli in IBS and healthy controls were included. Data were pooled for meta-analyses and effect sizes were calculated with 95% confidence interval (CIs).

Results: Our search strategy identified 809 studies of which 32 studies met the inclusion criteria. Reduced rectal pain thresholds was more common in IBS patients compared to healthy controls with an effect size of 1.00 95% CIs (0.77-1.24) (p < 0.0001) (I² = 78.6%). The pediatric IBS population had lower pain thresholds than adult IBS populations (p = 0.05) but no difference based on IBS diagnostic criteria, subtype or sex.

Conclusion & inferences: The results suggest that reduced rectal pain threshold to experimental stimulation is far more common in IBS patients than healthy controls. Further research is required to understand the pathophysiological and therapeutic implications of rectal sensitivity such as its role in measuring response to treatment and prognosis in IBS.