Table 1.
Characteristics of the axSpA patients from the ASAS-PerSpA study analysed in this study, stratified by geographical region
| Characteristics | Total (N = 2579) | Asia (n = 574) | Europe and North America (n = 988) | Latin America (n = 246) | Middle East and North Africa (n = 771) |
|---|---|---|---|---|---|
| Gender, male, % | 69 | 79 | 65 | 70 | 65 |
| Age, years, median (IQR) | 40 (31–51) | 34 (27–45) | 44 (35–53) | 42 (34–53) | 39 (32–49) |
| Symptom duration, years, median (IQR) | 11 (5–19) | 8 (4–15) | 13 (7–24) | 12 (5–20) | 10 (5–16) |
| HLA-B27 positive, % | 79** | 89* | 79** | 81** | 67*** |
| IBP (ASAS definition)a, % | 94 | 91 | 95 | 96 | 95 |
| Positive family history, % | 34 | 30 | 38 | 27 | 36 |
| Peripheral arthritis, % | 44 | 52 | 38 | 72 | 36 |
| Enthesitis, % | 45 | 53 | 37 | 71 | 42 |
| Dactylitis, % | 6 | 7 | 5 | 16 | 3 |
| Psoriasis, % | 8 | 4 | 13 | 4 | 5 |
| IBD, % | 5 | 1 | 7 | 4 | 6 |
| Acute anterior uveitis, % | 22 | 24 | 25 | 31 | 15 |
| Elevated CRP, % | 70 | 74 | 66 | 77 | 70 |
| Sacroiliitis on radiographsb, % | 78 | 85 | 73 | 75* | 79 |
| Sacroiliitis on MRIb, % | 82*** | 78*** | 77*** | 81*** | 93*** |
| SpA featuresc, mean (s.d.) | 4 (2) | 4 (1) | 4 (2) | 4 (2) | 3 (2) |
| Use of bDMARD, % | 33* | 39** | 25 | 58 | 31* |
| Use of NSAID, % | 99* | 99** | 99 | 99 | 98* |
| LOC regarding axSpA, mean (s.d.) | 8 (3) | 7 (3) | 8 (3) | 7 (4) | 9 (2) |
a
Four of five of the following features: onset before the age of 40 years, insidious onset, improvement with exercise, no improvement with rest, pain at night [21]. bBased on reading of local radiologists. cExcluding HLA-B27 status and sacroiliitis on imaging. *5–10% missing values **10–20% missing values ***20–40% missing values. bDMARD: biologic DMARD; LOC: level of confidence regarding the diagnosis.