title: Radiographic hip involvement in ankylosing spondylitis: factors associated with severe hip diseases.
abstract: OBJECTIVE
  To determine the factors associated with severe radiographic hip involvement in patients with ankylosing spondylitis (AS).
  
  
  METHODS
  A cross-sectional retrospective study was performed. The patients were classified into 3 groups based on the Bath Ankylosing Spondylitis Radiology Hip Index (BASRI-hip): minimal hip disease, moderate hip disease, and severe hip disease. Demographic, clinical, radiographic, and laboratory data were collected and analyzed. To identify factors associated with severe hip disease, ordinal regression analyses were performed.
  
  
  RESULTS
  A total of 256 patients were involved in the study. There were differences in the age at onset, delay in diagnosis, bilateral hip involvement, sacroiliitis, Schober's index, and occiput-to-wall distance among the 3 groups (p < 0.05). The patients with severe hip disease had lower C-reactive protein and erythrocyte sedimentation rate levels than did the minimal group (p < 0.05). The functional status based on the Bath Ankylosing Spondylitis Functional Index and the Harris Hip Score showed significant differences (p < 0.05). The results of the ordinal regression analyses showed that bilateral hip involvement, sacroiliitis, delay in diagnosis, age at onset, and spinal involvement were associated with a higher BASRI-hip (p < 0.05).
  
  
  CONCLUSIONS
  Bilateral hip involvement, severe sacroiliitis, longer delay in diagnosis, early disease onset, and spinal involvement are associated with severe hip disease in patients with AS. The severity of hip involvement is associated with the functional status in AS.
authors.affiliation: From the Department of Orthopedics, Changhai Hospital, Second Military Medical University, Shanghai; Department of Orthopedics, No. 401 Hospital, Jinan Military Region of PLA, Qingdao City, Shandong Province; Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin, China.J. Zhao, MD, Department of Orthopedics, No. 401 Hospital; W. Zheng, MD; J. Li, MD; D. Liu, MD; W. Xu, MD, Department of Orthopedics, Changhai Hospital, Second Military Medical University; C. Zhang, MD, Department of Orthopedics, Tianjin Medical University General Hospital.
authors.forename: Jinzhu
authors.initials: J
authors.lastname: Zhao
authors.affiliation: From the Department of Orthopedics, Changhai Hospital, Second Military Medical University, Shanghai; Department of Orthopedics, No. 401 Hospital, Jinan Military Region of PLA, Qingdao City, Shandong Province; Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin, China.J. Zhao, MD, Department of Orthopedics, No. 401 Hospital; W. Zheng, MD; J. Li, MD; D. Liu, MD; W. Xu, MD, Department of Orthopedics, Changhai Hospital, Second Military Medical University; C. Zhang, MD, Department of Orthopedics, Tianjin Medical University General Hospital.
authors.forename: Wei
authors.initials: W
authors.lastname: Zheng
authors.affiliation: From the Department of Orthopedics, Changhai Hospital, Second Military Medical University, Shanghai; Department of Orthopedics, No. 401 Hospital, Jinan Military Region of PLA, Qingdao City, Shandong Province; Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin, China.J. Zhao, MD, Department of Orthopedics, No. 401 Hospital; W. Zheng, MD; J. Li, MD; D. Liu, MD; W. Xu, MD, Department of Orthopedics, Changhai Hospital, Second Military Medical University; C. Zhang, MD, Department of Orthopedics, Tianjin Medical University General Hospital.
authors.forename: Chao
authors.initials: C
authors.lastname: Zhang
authors.affiliation: From the Department of Orthopedics, Changhai Hospital, Second Military Medical University, Shanghai; Department of Orthopedics, No. 401 Hospital, Jinan Military Region of PLA, Qingdao City, Shandong Province; Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin, China.J. Zhao, MD, Department of Orthopedics, No. 401 Hospital; W. Zheng, MD; J. Li, MD; D. Liu, MD; W. Xu, MD, Department of Orthopedics, Changhai Hospital, Second Military Medical University; C. Zhang, MD, Department of Orthopedics, Tianjin Medical University General Hospital.
authors.forename: Jia
authors.initials: J
authors.lastname: Li
authors.affiliation: From the Department of Orthopedics, Changhai Hospital, Second Military Medical University, Shanghai; Department of Orthopedics, No. 401 Hospital, Jinan Military Region of PLA, Qingdao City, Shandong Province; Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin, China.J. Zhao, MD, Department of Orthopedics, No. 401 Hospital; W. Zheng, MD; J. Li, MD; D. Liu, MD; W. Xu, MD, Department of Orthopedics, Changhai Hospital, Second Military Medical University; C. Zhang, MD, Department of Orthopedics, Tianjin Medical University General Hospital.
authors.forename: Denghui
authors.initials: D
authors.lastname: Liu
authors.affiliation: From the Department of Orthopedics, Changhai Hospital, Second Military Medical University, Shanghai; Department of Orthopedics, No. 401 Hospital, Jinan Military Region of PLA, Qingdao City, Shandong Province; Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin, China.J. Zhao, MD, Department of Orthopedics, No. 401 Hospital; W. Zheng, MD; J. Li, MD; D. Liu, MD; W. Xu, MD, Department of Orthopedics, Changhai Hospital, Second Military Medical University; C. Zhang, MD, Department of Orthopedics, Tianjin Medical University General Hospital. proxuwd@hotmail.com.
authors.forename: Weidong
authors.initials: W
authors.lastname: Xu
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D003430:Cross-Sectional Studies; D057210:Delayed Diagnosis; D004185:Disability Evaluation; D005260:Female; D006621:Hip Joint / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012189:Retrospective Studies; D058566:Sacroiliitis / Q000000981:diagnostic imaging*; D012720:Severity of Illness Index; D013167:Spondylitis, Ankylosing / Q000000981:diagnostic imaging*; D055815:Young Adult
keywords: ANKYLOSING SPONDYLITIS; HIP INVOLVEMENT; RADIOGRAPHIC