Patients with ankylosing spondylitis have high risk of irritable bowel syndrome: a long-term nationwide population-based cohort study

ABSTRACT

Objective

Ankylosing spondylitis (AS) is a chronic inflammatory disease, might carry a high risk of irritable bowel syndrome (IBS) due to abnormal gut microbiota or inflammatory reaction.

Methods

We conducted a 14-year retrospective cohort study based on Taiwan’s National Health Insurance Research Database (NHIRD). A total of 4007 patients with newly diagnosed AS (outpatient visits≧3 times, or hospitalization≧1 time) and 988,084 non-AS comparisons were enrolled during 2000–2012. To ensure baseline comparability, the propensity score was matched by age, gender, comorbidities, and other possible confounders. The outcome was the incidence of IBS, followed up to the end of 2013. Cox proportional hazard model calculated adjusted hazard ratio (aHR) and the cumulative incidence of both groups was analyzed by the Kaplan-Meier method.

Result

After propensity score matching, baseline demographic characteristics were comparable between AS patients and the comparison group. The crude HR for IBS in the AS group was significantly higher 2.41 (95%C.I. = 1.84–3.16) than comparison group. After adjusting for possible confounders, adjusted HR was 2.50 (95%C.I. = 1.91–3.29). The cumulative incidence of IBS in AS was significantly higher than non-AS comparisons during the 14-year follow-up (P < 0.001).

Conclusion

This nationwide population-based cohort study showed that patients with AS have higher risks of IBS than those of the non-AS comparison group.

KEYWORDS:

• Ankylosing spondylitis
• irritable bowel syndrome
• population-based cohort study
• autoimmune disease
• microbiota

Acknowledgments

H.-Y.F. designed the research study, analyzed all data, wrote and revised the manuscript. Y.-C.C. and X.-M.Q. analyzed all data, and wrote the manuscript. C.-H.C.: assisted in study design, writing the manuscript, and supervised all aspects of the research. Y.-H.W.: designed the research study, and acquired and analyzed all data. J.C.-C.W.: designed the research study, and supervised all aspects of the research.

Disclosure of Statement

The authors have no relevant conflicts of interest to disclose.

Ethics approval

Chung Shan Medical University Institutional Review Board number CS13021.

Additional information

Funding

No funding was received for the production of this work.