title: Risk factors of uveitis in ankylosing spondylitis: An observational study.
abstract: BACKGROUND
  Uveitis is the most common extra-articular manifestation in patients with ankylosing spondylitis (AS). The prevalence and characteristics of uveitis in AS have been studied in previous literatures, whereas its associated risk factors have not been clarified. Therefore, this study analyzed the risk factors of uveitis in patients with AS.
  
  
  METHODS
  A total of 390 patients with AS who fulfilled the modified New York criteria were enrolled from January to December in 2015. The history of uveitis was accepted only if diagnosed by ophthalmologists. The medical records of the patients were retrospectively reviewed and associated information was collected, such as disease duration, HLA-B27, and the number of peripheral arthritis. Hip-joint lesion was identified by imaging examination. Meanwhile, biochemical examinations were performed to determine the patient's physical function.
  
  
  RESULTS
  Of 390 patients with AS (80.5% male, mean age 33.3 years), 38 (9.7%) had experienced 1 or more episodes of uveitis. The incidence rate for hip-joint lesion was obviously higher for patients with uveitis than the nonuveitis group (44.7% vs 22.2%; P < 0.01). The number of peripheral arthritis was also larger for the uveitis group than nonuveitis group (2.18 ± 0.23 vs 0.55 ± 0.04; P < 0.001). Meanwhile, patients with uveitis had a significantly higher level of antistreptolysin O (ASO) and circulating immune complex (CIC) than those without (P < 0.05 and P < 0.0001, respectively). However, there were no significant differences in disease duration, HLA-B27, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) between the 2 groups. Binary logistic regression results showed that ASO (OR = 12.2, 95% CI:3.6-41.3, P < 0.01) and the number of peripheral arthritis (OR = 4.1, 95%CI:2.6-6.3, P < 0.01) are significantly associated with uveitis in AS.
  
  
  CONCLUSIONS
  This study provides some evidence that hip-joint lesion, the number of peripheral arthritis, ASO, and CIC may be associated with higher rates of uveitis in AS. The results of this comprehensive analysis suggest that the possible occurrence of uveitis in AS should not be neglected if the patients have those concomitant risk factors.
authors.affiliation: Department of Ophthalmology, the First Affiliated Hospital of Soochow University, Suzhou Department of Ophthalmology, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Jiangsu Province Institute of Traditional Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing Department of Nephrology and Rheumatology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China.
authors.forename: Li
authors.initials: L
authors.lastname: Sun
authors.forename: Rui
authors.initials: R
authors.lastname: Wu
authors.forename: Qin
authors.initials: Q
authors.lastname: Xue
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.forename: Peirong
authors.initials: P
authors.lastname: Lu
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000097:blood; D002648:Child; D002681:China; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D013167:Spondylitis, Ankylosing / Q000150:complications*; D014605:Uveitis / Q000209:etiology*
chemical_list: D015415:Biomarkers