Table 1

Characteristics of the study group*

Patients
CharacteristicHLA-B27+ healthy siblings (n=71)All patients (n=188)Patients with AS (n=120)Non-AS patients (n=67)
*AS, ankylosing spondylitis; non-AS, undifferentiated spondyloarthropathy (n=51), psoriatic arthritis (n=12), inflammatory bowel disease associated arthritis (n=4), and Reiter's syndrome (n=1); 95% CI, 95% confidence interval; NA, not applicable.
*Radiographic sacroiliitis of at least bilateral grade II or unilateral grade III. The number of patients evaluated in each group was 69, 187, 120, and 67 respectively; †Percentages are the sum of the percentages for Crohn's disease and ulcerative colitis.
Sex ratio, (male/female)0.651.141.50.4
Age, mean (95% CI)42 (38.3 to 44.9)42 (40.4 to 44.4)44 (41.5 to 46.5)40 (36.1 to 42.9)
Duration of disease, mean (95% CI)NA18 (16.4 to 20)22 (19.6 to 24.2)12 (9.3 to 14.1)
HLA-B27 positivity, No (%)71 (100)185 (98)120 (100)65 (96)
Axial symptoms, No (%)
    All0 (0)180 (96)120 (100)60 (88)
    Back or buttock inflammatory pain0 (0)179 (95)119 (99)60 (88)
    Sacroiliitis (pelvic x ray)*0/69 (0)120/187 (64)120 (100)0 (0)
Peripheral enthesitis, No (%)3 (4)109 (58)61 (51)50 (74)
Peripheral arthritis, No (%)1 (1)90 (48)59 (49)22 (32)
Uveitis, No (%)0 (0)57 (30)51 (42)6 (9)
Psoriasis, No (%)3 (4)35 (19)22 (18)13 (19)
Crohn/ulcerative colitis, No (%)†0/1 (1)3/5 (4)2/3 (4)1/2 (4)