Number of patients with the reported comorbidity categories at RA diagnosis and 12 months after diagnosis
| All at RA diagnosis | Seropositive RA at diagnosis | Seronegative RA at diagnosis | All at 12 months* | Seropositive RA at 12 months | Seronegative RA at 12 months | ΔRA diagnosis to 12 months | |
| n=13 505 | n=9255 | n=3866 | n=13 505 | n=9255 | n=3866 | All | |
| Cardiovascular, n (%) | 1195 (8.9) | 740 (8.0) | 422 (10.9) | 1447 (10.7) | 903 (9.8) | 501 (12.0) | 252 (1.9) |
| Non-cardiac vascular, n (%) | 3695 (27.4) | 2336 (25.2) | 1259 (32.6) | 4424 (32.8) | 2833 (30.6) | 1474 (38.1) | 729 (5.4) |
| Malignant, n (%) | 581 (4.3) | 348 (3.8) | 210 (5.4) | 819 (6.1) | 499 (5.4) | 286 (7.4) | 238 (1.8) |
| Endocrine, n (%) | 2623 (19.4) | 1749 (18.9) | 796 (20.6) | 2804 (20.8) | 1877 (20.3) | 843 (21.8) | 181 (1.3) |
| Gastrointestinal, n (%) | 879 (6.5) | 584 (6.3) | 273 (7.1) | 1112 (8.2) | 741 (8.0) | 345 (8.9) | 233 (1.7) |
| Infectious, n (%) | 832 (6.2) | 552 (6.0) | 262 (6.8) | 1168 (8.7) | 788 (8.5) | 351 (9.1) | 336 (2.5) |
| Chronic kidney disease, n (%) | 105 (0.8) | 69 (0.8) | 34 (0.9) | 165 (1.2) | 105 (1.1) | 56 (1.5) | 60 (0.4) |
| Neurological, n (%) | 929 (6.9) | 590 (6.4) | 316 (8.2) | 1145 (8.5) | 725 (7.8) | 390 (10.1) | 216 (1.6) |
| Psychiatric, n (%) | 1963 (14.5) | 1337 (14.5) | 568 (14.7) | 2346 (17.4) | 1593 (17.2) | 681 (17.6) | 383 (2.8) |
| Respiratory, n (%) | 727 (5.4) | 518 (5.6) | 191 (4.9) | 969 (7.2) | 709 (7.7) | 237 (6.1) | 242 (1.8) |
| No comorbidity, n (%) | 6057 (44.9) | 4330 (46.8) | 1559 (40.3) | 5164 (38.2) | 3721 (40.2) | 1303 (33.7) | −893 (−6.6) |
*Twelve months data calculated for all 13 505 patients. One hundred thirty-two patients had died or emigrated at 12 months, but were kept with their baseline comorbidities to be able to compare with the comorbidity situation at RA diagnosis. Missing information on serological status: 384 (2.8%). P values for testing marginal homogeneity were calculated by the McNemar test, <0.0001 for each comorbidity category.
RA, rheumatoid arthritis.