Table 3.
Comparison of demographic and clinical characteristics between the cases and controls*
| Total sample (n = 632) | Cases (n = 158) | Controls (n = 474) | P† | |
|---|---|---|---|---|
| Age, mean ± SD years | 46.7 ± 13.0 | 46.9 ± 13.2 | 46.6 ± 13.0 | 0.80 |
| Sex | 0.81 | |||
| Male | 255 (40.3) | 65 (41.1) | 190 (40.1) | |
| Female | 377 (59.7) | 93 (58.9) | 284 (59.9) | |
| Race | 0.96 | |||
| White | 487 (77.1) | 122 (77.2) | 365 (77.0) | |
| Other | 145 (22.9) | 36 (22.8) | 109 (23.0) | |
| Education | 0.13 | |||
| Some college | 386 (62.9) | 106 (68.0) | 280 (61.1) | |
| High school or less | 228 (37.1) | 50 (32.0) | 178 (38.9) | |
| Region | 0.034 | |||
| Northeast | 69 (10.9) | 19 (12.0) | 50 (10.6) | |
| Midwest | 143 (22.6) | 29 (18.4) | 119 (24.0) | |
| South | 326 (51.6) | 76 (48.1) | 250 (52.7) | |
| West | 94 (14.9) | 34 (21.5) | 60 (12.7) | |
| Diagnosis‡ | – | |||
| Psoriasis | 183 (27.6) | 51 (27.1) | 132 (19.9) | |
| Rheumatoid arthritis | 319 (48.0) | 92 (48.9) | 227 (47.7) | |
| Inflammatory bowel disease | 105 (15.8) | 29 (15.4) | 76 (16.0) | |
| Ankylosing spondylitis | 57 (8.6) | 16 (8.5) | 41 (8.6) | |
| TNF inhibitor prescribed | 0.84 | |||
| Adalimumab | 231 (36.5) | 60 (38.0) | 171 (36.1) | |
| Etanercept | 262 (41.5) | 61 (38.6) | 201 (42.4) | |
| Infliximab | 135 (21.4) | 36 (22.8) | 99 (20.9) | |
| Certolizumab | 4 (0.6) | 1 (0.6) | 3 (0.6) | |
| Diabetes mellitus | 0.058 | |||
| Yes | 91 (14.4) | 30 (19.0) | 61 (12.9) | |
| No | 541 (85.6) | 128 (81.0) | 413 (87.1) | |
| Prescribed trimethoprim/sulfamethoxazole | 0.077 | |||
| Yes | 51 (8.1) | 18 (11.4) | 33 (7.0) | |
| No | 281 (91.9) | 140 (88.6) | 441 (93.0) | |
| Prescribed prednisone | <0.001 | |||
| Yes | 264 (41.8) | 87 (55.1) | 177 (37.3) | |
| No | 368 (58.2) | 71 (44.9) | 297 (62.7) | |
| Prescribed medication conferring high risk of infection | 0.17 | |||
| Yes | 318 (50.3) | 87 (55.1) | 231 (48.7) | |
| No | 314 (49.7) | 71 (44.9) | 243 (51.3) | |
| Pre-drug screening test | 0.33 | |||
| Yes | 311 (49.2) | 83 (52.5) | 228 (48.1) | |
| No | 321 (50.8) | 75 (47.5) | 246 (51.9) | |
| Followup, mean ± SD days | 618.2 ± 235.4 | 621.8 ± 239.3 | 617.0 ± 234.3 | 0.83 |
*
Except where indicated otherwise, values are the number (%) of subjects. TNF = tumor necrosis factor.
†
By 2-sample t-test, chi-square test of association, or Fisher’s exact test.
‡
P values are not reported because patients may have had >1 diagnosis, and therefore, the groups are not mutually exclusive.