Baseline demographic characteristics stratified by frailty status
| SERA | UK biobank (RA population only) | |||||||||||
| Total (n=899) | Frailty index | Total (n=3605) | Frailty index* | Frailty phenotype† | ||||||||
| Robust (n=303) | Mild (n=487) | Moderate/severe (n=109) | Robust (n=773) | Mild (n=2001) | Moderate (n=714) | Severe (n=109) | Robust (n=788) | Prefrail (n=1775) | Frail (n=781) | |||
| Mean age | ||||||||||||
| Years (SD) | 58.3 (13.3) | 56.0 (13.6) | 58.5 (13.8) | 63.7 (12.3) | 59.5 (7.1) | 59.2 (7.2) | 59.5 (7.1) | 59.8 (6.9) | 58.2 (5.9%) | 58.8 (7.1) | 59.8 (7.1) | 59.0 (7.0) |
| Sex | ||||||||||||
| Male (%) | 313 (34.8) | 109 (36.0) | 171 (35.1) | 33 (30.3) | 1063 (29.5) | 255 (33.2) | 568 (28.4) | 208 (29.1) | 27 (24.8) | 278 (35.3) | 527 (29.7) | 193 (24.7) |
| Female (%) | 586 (65.2) | 194 (64.0) | 316 (64.9) | 76 (69.7) | 2542 (70.5) | 518 (66.8) | 1433 (71.6) | 506 (70.9) | 82 (75.2) | 510 (64.7) | 1248 (70.3) | 588 (75.3) |
| SES | ||||||||||||
| Quintile 1 (deprived) | 193 (21.6) | 60 (19.8) | 102 (21.1) | 31 (28.4) | 884 (24.5) | 115 (15.0) | 459 (23.0) | 255 (35.7) | 52 (47.7) | 132 (16.8) | 396 (22.3) | 270 (34.6) |
| 2 | 193 (21.6) | 58 (19.1) | 111 (23.0) | 24(22.0) | 790 (21.9) | 169 (21.9) | 449 (22.4) | 148 (20.7) | 22 (20.2) | 173 (22.0) | 385 (21.7) | 181 (23.2) |
| 3 | 174 (19.4) | 62 (20.5) | 90 (18.6) | 22 (20.2) | 698 (19.4) | 161 (20.9) | 391 (19.5) | 129 (18.1) | 15 (13.8) | 167 (21.2) | 336 (18.9) | 142 (18.2) |
| 4 | 191 (21.3) | 69 (22.8) | 108 (22.4) | 14 (12.8) | 593 (16.5) | 162 (20.8) | 328 (16.4) | 91 (12.7) | 12 (11.0) | 145 (18.4) | 314 (17.7) | 98 (12.5) |
| Quintile 5 (affluent) | 144 (16.1) | 54 (17.8) | 72 (14.9) | 18 (16.5) | 639 (17.7) | 166 (21.4) | 373 (18.6) | 91 (12.7) | 8 (7.3) | 171 (21.7) | 343 (19.3) | 90 (11.5) |
| Missing | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 |
| Smoking | ||||||||||||
| Never | 323 (35.9) | 115 (38.0) | 167 (34.3) | 41 (37.6) | 1624 (45.6) | 402 (52.5) | 894 (45.0) | 293 (41.6) | 35 (32.1) | 366 (46.7) | 810 (45.9) | 330 (42.9) |
| Previous | 326 (36.3) | 108 (35.6) | 181 (37.2) | 37 (33.9) | 1512 (42.4) | 295 (38.6) | 866 (43.6) | 303 (43.0) | 48 (44.0) | 346 (44.2) | 748 (42.4) | 317 (41.2) |
| Current | 249 (27.7) | 79 (26.1) | 139 (28.5) | 31 (28.4) | 429 (12.0) | 68 (8.9) | 227 (11.4) | 108 (15.3) | 26 (23.9) | 71 (9.1) | 205 (11.6) | 123 (16.0) |
| Missing | 1 | 1 | 0 | 0 | 40 | 8 | 14 | 10 | 0 | 5 | 12 | 11 |
| RA duration | ||||||||||||
| Median years (IQR) | – | – | – | – | 6.6 (3.0–10.7) | 6.2 (3.0–11.2) | 7.0 (3.2–11.0) | 6.2 (2.7–9.8) | 6.0 (2.8–9.4) | 5.9 (2.7–10.0) | 6.6 (3.0–10.8) | 7.0 (3.6–10.6) |
| Mean DAS-28 | ||||||||||||
| Score (SD) | 4.9 (1.3) | 4.1 (1.2) | 5.2 (1.1) | 6.0 (1.1) | – | – | – | – | – | – | – | – |
| Missing | 65 | 31 | 30 | 4 | ||||||||
| Mean HAQ-DI | ||||||||||||
| Score (SD) | 1.2 (0.8) | 0.5 (0.5) | 1.5 (0.6) | 2.2 (0.6) | ||||||||
| Missing | 2 | 2 | 0 | 0 | ||||||||
| Mean self-rated health | ||||||||||||
| Score (SD) | 55.4 (25.8) | 25.9 (24.0) | 50.0 (23.2) | 39.2 (22.8) | ||||||||
| Missing | 7 | 3 | 3 | 1 | ||||||||
*Eight UK Biobank participants had missing values for the frailty index and are excluded from columns stratified by frailty index.
†A total of 262 UK Biobank participants had missing data for the frailty phenotype and are excluded from columns stratified by frailty phenotype status.
DAS-28, Disease Activity Score in 28 joints; HAQ-DI, Health Assessment Questionnaire – Disability Index; RA, rheumatoid arthritis; SERA, Scottish Early Rheumatoid Arthritis; SES, socioeconomic status.