Table 1.
Baseline characteristics, total cohort and stratified by baseline physical activity level
| Total cohort | No physical activity | Low physical activity | High physical activity | ||
|---|---|---|---|---|---|
|
|
|||||
| Variable | Median (IQR)/ N (%) [% missing] | Median (IQR)/ N (%) [% missing] | Median (IQR)/ N (%) [% missing] | Median (IQR)/ N (%) [% missing] | P |
| N | 1468 | 408 (27.8) | 518 (35.3) | 542 (36.9) | |
| Age, years | 60 (50, 69) [0] | 59 (50, 68) [0] | 59 (48, 68) [0] | 62 (51, 70) [0] | <0.001a |
| Female, N (%) | 957 (65.2) [0] | 285 (69.9) [0] | 349 (67.4) [0] | 323 (59.6) [0] | <0.001b |
| Symptom duration, months | 6.2 (3.7, 10.7) [0] | 6.1 (3.4, 10.0) [0] | 6.4 (3.8, 11.5) [0] | 6.2 (3.7, 10.2) [0] | 0.114a |
| Ethnicity | |||||
| White | 1380 (94.0) | 373 (91.4) | 486 (93.8) | 521 (96.1) | |
| Non-white | 69 (4.7) | 31 (7.6) | 25 (4.8) | 13 (2.4) | |
| Missing | 19 (1.3) | 4 (1.0) | 7 (1.4) | 8 (1.5) | <0.001b |
| IMD quintile | |||||
| 1 (most deprived) | 141 (9.6) | 53 (13.0) | 45 (8.7) | 43 (7.9) | <0.001b |
| 2 | 252 (17.2) | 90 (22.1) | 70 (13.5) | 92 (17.0) | |
| 3 | 224 (15.3) | 48 (11.8) | 93 (18.0) | 83 (15.3) | |
| 4 | 320 (21.8) | 85 (20.8) | 116 (22.4) | 119 (22.0) | |
| 5 (least deprived) | 289 (19.7) | 68 (16.7) | 106 (20.5) | 115 (21.2) | |
| Missing | 242 (16.5) | 64 (15.7) | 88 (17.0) | 90 (16.6) | |
| Smoking status | |||||
| Never | 572 (39.0) | 147 (36.0) | 213 (41.1) | 212 (39.1) | <0.001b |
| Former | 600 (40.9) | 168 (41.2) | 195 (37.6) | 237 (43.7) | |
| Current | 284 (19.3) | 89 (21.8) | 107 (20.7) | 88 (16.2) | |
| Missing | 12 (0.8) | 4 (1.0) | 3 (0.6) | 5 (0.9) | |
| BMI, continuous | 27.2 (24.1, 31.2) [8.3] | 28.5 (24.8, 32.6) [9.1] | 27.2 (24.3, 31.6) [8.1] | 26.2 (23.5, 30.0) [7.9] | <0.001a |
| BMI categories | |||||
| Underweight | 13 (0.9) | 4 (1.0) | 4 (0.8) | 5 (0.9) | <0.001b |
| Normal | 438 (29.8) | 98 (24.0) | 156 (30.1) | 184 (33.9) | |
| Overweight | 462 (31.5) | 125 (30.6) | 153 (29.5) | 184 (33.9) | |
| Obese | 433 (29.5) | 144 (35.3) | 163 (31.5) | 126 (23.2) | |
| Missing | 122 (8.3) | 37 (9.1) | 42 (8.1) | 43 (7.9) | |
| DAS28 | 4.2 (3.2, 5.2) [5.9] | 4.6 (3.7, 5.6) [5.9] | 4.2 (3.2, 5.1) [6.6] | 3.8 (3.0, 4.7) [5.4] | <0.001a |
| DAS28-2C | 3.3 (2.2, 4.5) [5.1] | 3.6 (2.5, 4.8) [4.7] | 3.3 (2.2, 4.4) [5.6] | 3.1 (2.0, 4.2) [5.0] | <0.001a |
| HAQ | 1.0 (0.4, 1.6) [0.7] | 1.5 (0.9, 2.0) [1.2] | 1.0 (0.4, 1.5) [0.4] | 0.8 (0.3, 1.3) [0.6] | <0.001a |
| Pain VAS (0–100) | 48 (25, 70) [2.2] | 59 (36, 77) [1.5] | 47 (23, 69) [2.1] | 43 (22, 65) [2.8] | <0.001a |
| Fatigue VAS (0–100) | 51 (23, 73) [2.1] | 61 (36, 76) [1.0] | 50 (23, 72) [3.3] | 44 (18, 70) [1.9] | <0.001a |
| HADS Depression | 5 (2, 8) [1.3] | 8 (4, 10) [2.7] | 5 (2, 8) [0.8] | 4 (2, 7) [0.7] | <0.001a |
| HADS Anxiety | 6 (3, 9) [1.5] | 7 (4, 11) [3.2] | 6 (3, 9) [0.8] | 5 (3, 9) [0.9] | <0.001a |
| RF | |||||
| Positive | 744 (50.7) | 219 (53.7) | 253 (48.8) | 272 (50.2) | 0.005b |
| Negative | 392 (26.7) | 94 (23.0) | 143 (27.6) | 155 (28.6) | |
| Missing | 332 (22.6) | 95 (23.3) | 122 (23.6) | 115 (21.2) | |
| Comorbidities | |||||
| None | 579 (39.4) | 153 (37.5) | 200 (38.6) | 226 (41.7) | 0.003b |
| 1 | 477 (32.5) | 126 (30.9) | 170 (32.8) | 181 (33.4) | |
| ≥2 | 411 (28.0) | 129 (31.6) | 147 (28.4) | 135 (24.9) | |
| Missing | 1 (0.1) | 0 (0) | 1 (0.2) | 0 (0) | |
a
Kruskal–Wallis test.
b
Chi2 test.
DAS28-2C: 2-component DAS28; HADS: Hospital Anxiety and Depression Scale; IMD: Index of Multiple Deprivation; IQR: interquartile range; VAS: visual analogue scale.