Clinical and immunogenetic prognostic factors for radiographic severity in ankylosing spondylitis.
OBJECTIVE
To improve prognostic ability in ankylosing spondylitis (AS), we sought to identify demographic, clinical, and immunogenetic characteristics associated with radiographic severity in a large cohort of patients.


METHODS
Patients with AS for > or =20 years were enrolled in a cross-sectional study (n = 398). Pelvic and spinal radiographs were scored using the Bath Ankylosing Spondylitis Radiology Index for the spine (BASRI-s), and radiographic severity was measured as the BASRI-s/duration of AS. Clinical factors and HLA-B, DR, DQ, and DP alleles associated with the highest quartile of the distribution of radiographic severity were identified by first using random forests and then using multivariable logistic regression modeling. Similar procedures were used to identify factors associated with the lowest quartile of radiographic severity.


RESULTS
Radiographic severity (being in the top quartile of BASRI-s/duration of AS) was associated with older age at onset of AS (odds ratio [OR] 1.10 per year), male sex (OR 1.90), current smoker (OR 4.72), and the presence of HLA-B*4100 (OR 11.73), DRB1*0804 (OR 12.32), DQA1*0401 (OR 5.24), DQB1*0603 (OR 3.42), and DPB1*0202 (OR 23.36), whereas the presence of DRB1*0801 was strongly negatively associated (OR 0.03). Being in the lowest quartile of BASRI-s/duration of AS was also less likely among those with an older age at onset of AS (OR 0.94 per year), men (OR 0.28), and current smokers (OR 0.29).


CONCLUSIONS
The accuracy of the prognosis of radiographic severity in AS is improved by knowing the age at disease onset, sex, smoking history, and the presence of HLA-B*4100, DRB1*0804, DQA1*0401, DQB1*0603, DRB1*0801, and DPB1*0202 alleles.
Ward
Michael M
MM
National Institute of Arthritis and Musculoskeletal and Skin Diseases, NIH, Bethesda, MD 20892, USA. wardm1@mail.nih.gov
Hendrey
Matthew R
MR
Malley
James D
JD
Learch
Thomas J
TJ
Davis
John C
JC
Reveille
John D
JD
Weisman
Michael H
MH
D017668:Age of Onset; D000368:Aged; D000483:Alleles; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D006680:HLA Antigens / Q000235:genetics*; D015235:HLA-B Antigens / Q000235:genetics; D006682:HLA-DP Antigens / Q000235:genetics; D059868:HLA-DP beta-Chains; D006683:HLA-DQ Antigens / Q000235:genetics; D059848:HLA-DQ alpha-Chains; D059866:HLA-DQ beta-Chains; D006684:HLA-DR Antigens / Q000235:genetics; D059811:HLA-DRB1 Chains; D006801:Humans; D008297:Male; D008875:Middle Aged; D010384:Pelvic Bones / Q000000981:diagnostic imaging*; D011379:Prognosis; D011446:Prospective Studies; D011859:Radiography; D012720:Severity of Illness Index; D012737:Sex Factors; D012907:Smoking; D013131:Spine / Q000000981:diagnostic imaging*; D013167:Spondylitis, Ankylosing / Q000175:diagnosis / Q000235:genetics* / Q000276:immunology*
D006680:HLA Antigens; D015235:HLA-B Antigens; C543504:HLA-B*41 antigen; D006682:HLA-DP Antigens; D059868:HLA-DP beta-Chains; C512822:HLA-DPB1*02:02 antigen; D006683:HLA-DQ Antigens; D059848:HLA-DQ alpha-Chains; D059866:HLA-DQ beta-Chains; C069050:HLA-DQA1 antigen; C069051:HLA-DQB1 antigen; D006684:HLA-DR Antigens; D059811:HLA-DRB1 Chains; C466440:HLA-DRB1*08:01 antigen