Table 1.
Baseline characteristics compared according to depression symptom categories
| ‘None’ (n = 374) | Mild (n = 192) | Moderate–severe (n = 176) | P-value | |
|---|---|---|---|---|
| Age, mean (s.d.), years | 45.3 (14.6) | 45.5 (13.6) | 45.5 (12.8) | 0.97 |
| Males, n (%) | 248 (66) | 133 (69) | 115 (65) | 0.69 |
| Meeting modified New York criteria, n (%) | 221 (59) | 118 (61) | 96 (55) | 0.40 |
| Age at symptom onset, mean (s.d.), years | 28.0 (10.7) | 29.5 (12.2) | 29.4 (12.3) | 0.21 |
| Symptom duration, mean (s.d.), years | 17.3 (13.4) | 16.0 (12.5) | 16.1 (13.1) | 0.43 |
| HLA-B27 positive, n (%) | 218 (78) | 106 (75) | 90 (70) | 0.23 |
| BMI, mean (s.d.), kg/m2 | 27.2 (5.2) | 29.0 (6.1) | 28.8 (6.5) | 0.002 |
| Education, n (%) | ||||
| Secondary school | 107 (29) | 71 (37) | 22 (50) | 0.006 |
| Apprenticeship | 36 (10) | 16 (8) | 4 (9) | |
| Further education college | 110 (29) | 62 (33) | 15 (34) | |
| University degree | 93 (25) | 34 (18) | 2 (5) | |
| Further degree | 28 (7) | 7 (4) | 1 (2) | |
| IMD, mean (s.d.) | 2.9 (1.4) | 3.1 (1.4) | 3.3 (1.4) | 0.004 |
| NSAID use in past 6 months, n (%) | 277 (75) | 138 (74) | 123 (71) | 0.62 |
| DMARD use in past 6 months, n (%) | 44 (12) | 25 (14) | 38 (22) | 0.009 |
| ASDAS, mean (s.d.) | 2.6 (0.8) | 3.1 (0.7) | 3.3 (0.7) | <0.001 |
| BASDAI, median (IQR) | 6.0 (4.5, 7.2) | 7.0 (6.0, 7.8) | 7.7 (6.9, 8.9) | <0.001 |
| Spinal pain, median (IQR) | 6.0 (4.0, 7.0) | 7.0 (6.0, 8.0) | 8.0 (6.0, 9.0) | <0.001 |
| BASFI, median (IQR) | 5.4 (3.3, 7.0) | 6.9 (5.4, 8.3) | 8.1 (6.8, 9.1) | <0.001 |
| ASQoL, median (IQR) | 10.0 (7.0, 13.0) | 14.0 (12.0, 16.0) | 16.0 (14.0, 17.0) | <0.001 |
| Fatiguea, median (IQR) | 15.0 (12.0, 19.0) | 18.0 (16.0, 22.0) | 22.0 (18.0, 26.5) | <0.001 |
| History of physician diagnosed depression, n (%) | 31 (8) | 31 (16) | 51 (29) | <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.