Lack of association between the Dudley Inflammatory Bowel Symptom Questionnaire and fecal calprotectin in axial spondyloarthritis: a cross-sectional study.

To investigate the relationship between gastrointestinal symptom burden assessed by the Dudley Inflammatory Bowel Symptom Questionnaire (DISQ), fecal calprotectin (FC), a non-invasive biomarker suggestive of intestinal inflammation, disease activity, and clinical characteristics in patients with axial spondyloarthritis (axSpA). In this cross-sectional study, 174 patients with axSpA were enrolled. Gastrointestinal symptom burden was assessed using the DISQ, disease activity using the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), functional status using the Bath Ankylosing Spondylitis Functional Index (BASFI), and health-related quality of life using the Short Form-36 (SF-36). FC levels were measured by enzyme-linked immunosorbent assay. Correlation analyses, receiver operating characteristic (ROC) analyses, and multivariable logistic regression models were performed. FC levels were normal (< 50 μg/g) in 52.9%, mildly elevated (50-200 μg/g) in 38.5%, and markedly elevated (> 200 μg/g) in 8.6%. DISQ scores demonstrated a moderate positive correlation with BASDAI (rs = 0.432, p < 0.001) and a weak positive correlation with BASFI (rs = 0.248, p < 0.001), while showing moderate inverse correlations with all SF-36 domains (rs = - 0.310 to -0.470, all p < 0.001). In contrast, DISQ scores were not associated with FC levels (rs = 0.066, p = 0.386), ESR (rs = 0.013, p = 0.868), or CRP (rs = 0.029, p = 0.706). ROC analyses demonstrated poor discriminatory performance between DISQ and FC (AUC 0.529 and 0.475, respectively). In multivariable analyses, BASDAI independently predicted clinically significant gastrointestinal symptoms (OR 1.635, 95% CI 1.285-2.081) and elevated FC levels (OR 1.254, 95% CI 1.004-1.567), whereas neither DISQ nor FC independently predicted the other. Gastrointestinal symptom burden assessed by the DISQ was associated with disease activity, functional impairment, and reduced quality of life, but not with FC levels in axSpA.