Development of ankylosing spondylitis in patients with ulcerative colitis: A systematic meta-analysis

Ulcerative colitis (UC) is a manifestation of inflammatory bowel disease (IBD), which can cause inflammation of the intestinal tract. Ankylosing spondylitis (AS) is an inflammatory disease of the sacroiliac joints. Many studies have found that some UC patients progress to AS. In this study, we conducted a literature search and meta-analysis to investigate the prevalence of AS among UC patients during follow-up. The studies related to the AS among patients with UC were obtained from PubMed, Web of Science, Embase, and Cochrane Library databases since its inception-December 2022. The literature was screened strictly according to inclusion and exclusion criteria. Forest plots were used to detect the overall incidence of AS in UC and to compare the risk ratios for the development of AS in the UC. The heterogeneity of studies was assessed using I2 statistical methods. 1) 17 studies with 98704 UC patients were included. 2)700 UC patients developed AS during follow-up (1.66%, 95% CI: 0.89-2.62%). Human leukocyte antigen B27 (HLA-B27) was reported in 3 studies. HLA-B27 positivity was significantly higher than the incidence of HLA-B27 negativity in AS patients (68.29% vs 31.71%, P < 0.0001). There was significantly increased risk of AS development in HLA-B27 positive IBD patients (RR: 22.17, 95% CI: 11.79-41.66, P < 0.0001). 3)The definite follow-up time was reported in 12 studies (range: 0.3-40 years). After follow-up for ≥5 years, the incidence of AS among patients with UC was 1.75% (95% CI: 0.62-3.37%). Meanwhile, after follow-up for