Table 2.
Baseline characteristics compared according to anxiety symptom categories
| None (n = 278) | Mild (n = 169) | Moderate–severe (n = 295) | P-value | |
|---|---|---|---|---|
| Age, mean (s.d.), years | 47.0 (14.7) | 45.5 (13.9) | 43.8 (13.0) | 0.022 |
| Males, n (%) | 188 (68) | 120 (71) | 188 (64) | 0.27 |
| Meeting modified New York criteria, n (%) | 165 (59) | 106 (63) | 164 (56) | 0.32 |
| Age at symptom onset, mean (s.d.), years | 28.3 (11.6) | 29.3 (11.1) | 28.8 (11.8) | 0.66 |
| Symptom duration, mean (s.d.), years | 18.7 (13.4) | 16.2 (13.1) | 15.0 (12.5) | 0.003 |
| HLA-B27 positive, n (%) | 174 (81) | 83 (70) | 157 (73) | 0.047 |
| BMI, mean (s.d.), kg/m2 | 27.8 (5.5) | 27.8 (5.1) | 28.5 (6.4) | 0.39 |
| Education, n (%) | ||||
| Secondary school | 89 (32) | 60 (36) | 102 (35) | 0.067 |
| Apprenticeship | 29 (10) | 14 (8) | 27 (9) | |
| Further education college | 81 (29) | 42 (25) | 104 (36) | |
| University degree | 62 (22) | 45 (27) | 42 (14) | |
| Further degree | 16 (6) | 8 (5) | 15 (5) | |
| IMD, mean (s.d.) | 2.8 (1.4) | 3.0 (1.3) | 3.2 (1.4) | 0.011 |
| NSAID use in past 6 months, n (%) | 205 (75) | 125 (75) | 208 (72) | 0.56 |
| DMARD use in past 6 months, n (%) | 43 (16) | 18 (11) | 46 (16) | 0.30 |
| ASDAS, mean (s.d.) | 2.6 (0.9) | 2.9 (0.7) | 3.1 (0.8) | <0.001 |
| BASDAI, median (IQR) | 5.9 (4.4, 7.2) | 6.6 (5.5, 7.4) | 7.4 (6.2, 8.5) | <0.001 |
| Spinal pain, median (IQR) | 6.0 (4.0, 8.0) | 7.0 (5.0, 8.0) | 7.0 (6.0, 8.0) | <0.001 |
| BASFI, median (IQR) | 5.6 (3.3, 7.1) | 6.3 (4.6, 8.1) | 7.2 (5.7, 8.6) | <0.001 |
| ASQoL, median (IQR) | 10.0 (6.0, 13.0) | 12.0 (10.0, 15.0) | 15.0 (12.0, 17.0) | <0.001 |
| Fatiguea, median (IQR) | 15.0 (12.0, 19.0) | 17.0 (14.0, 21.0) | 20.0 (17.0, 24.0) | <0.001 |
aThe Chalder Fatigue Scale ranges from 0 (low) to 33 (high). ASDAS: AS disease activity score; ASQoL: AS quality of life questionnaire; BASDAI: Bath AS disease activity index; BASFI: Bath AS functional index; IMD: index of multiple deprivation with 1 (least deprived) to 5 (most); IQR: interquartile range.