LAUSR

OBJECTIVES To determine the frequency of symptoms meeting Rome IV functional bowel disorder (FBD) in patients with ankylosing spondylitis (AS), investigate factors associated with FBD symptoms, and assess whether having FBD symptoms might influence AS disease activity. METHODS In this cross-sectional study, we enrolled 153 AS patients without known colonic ulcer and 56 sex- and age-matched controls to evaluate FBD (or its subtypes) symptoms. Disease characteristics were also evaluated in AS group. RESULTS Sixty (39.2%) of 153 AS patients had FBD symptoms, which was more prevalent than controls (23.2%). Besides, symptoms compatible with irritable bowel syndrome (IBS) and chronic diarrhea were detected in 18 and 43 AS patients respectively. For AS group, multivariable logistic regression analyses showed that symptoms of FBD, IBS, and chronic diarrhea were negatively associated with using non-steroidal anti-inflammatory drug (NSAID), and positively associated with comorbid fibromyalgia, respectively. In exploration about effects of FBD (or its subtypes) symptoms on AS disease activity by multivariable linear regression analyses, FBD symptoms and chronic diarrhea had universal positive associations with assessments of AS disease characteristics respectively. CONCLUSION Patients with AS had frequent symptoms compatible with FBD, IBS, and chronic diarrhea, proportions of which were lower in those with NSAID-use. The improvement of FBD symptoms and chronic diarrhea might be conducive to disease status of AS patients.