Table 1.
Baseline Characteristics of individuals at cohort entry
| Characteristic | Group | RA | IBD | ||
|---|---|---|---|---|---|
| + NMSC (n=932) | − NMSC (n=5909) | + NMSC (n=381) | − NMSC (n=2407) | ||
| Age | < 50 | <10 | 63 (1.1%) | 12 (3.1%) | 48 (2.0%) |
| 51–60 | 23 (2.5%) | 216 (3.7%) | <10 | 89 (3.7%) | |
| 61–70 | 268 (28.8%) | 1633 (27.6%) | 113 (29.7%) | 674 (28.0%) | |
| 71–80 | 453 (48.6%) | 2635 (44.6%) | 179 (47.0%) | 1035 (43.0%) | |
| 81+ | 183 (19.6%) | 1362 (23.0%) | 73 (19.2%) | 561 (23.3%) | |
| Criteria for initial Medicare eligibility | Old Age and Survivors Insurance | 757 (81.2%) | 4609 (78.0%) | 329 (86.4%) | 2031 (84.4%) |
| Disability and/or ESRD | 175 (18.8%) | 1300 (22.0%) | 52 (13.6%) | 376 (15.6%) | |
| Sex | Female | 582 (62.4%) | 4310 (72.9%) | 200 (52.5%) | 1432 (59.5%) |
| Male | 350 (37.6%) | 1599 (27.1%) | 181 (47.5%) | 975 (40.5%) | |
| Race | White | 925 (99.2%) | 5802 (98.2%) | 376 (98.7%) | 2375 (98.7%) |
| Black | <10 | <10 | <10 | <10 | |
| Other | <10 | 98 (1.7%) | <10 | 27 (1.1%) | |
| Hispanic Ethnicity | <10 | 133 (2.3%) | <10 | 28 (1.2%) | |
| Residence | Rural | 280 (30.0%) | 1861 (31.9%) | 86 (22.6%) | 584 (24.8%) |
| Urban | 652 (70.0%) | 3981 (68.1%) | 294 (77.4%) | 1774 (75.2%) | |
| Latitude (at or above median) | At or above median | 445 (47.7%) | 2948 (49.9%) | 173 (45.5%) | 1196 (49.7%) |
| Below median | 487 (52.3%) | 2961(50.1%) | 208(54.6%) | 1211(50.3%) | |
| Skilled nursing facility | Yes | 43 (4.6%) | 457 (7.7%) | 18 (4.7%) | 196 (8.1%) |
| Charlson co-morbidity score | 0 | 413 (44.3%) | 2527 (42.8%) | 182 (47.8%) | 1092 (45.4%) |
| 1 | 137 (14.7%) | 930 (15.7%) | 54 (14.2%) | 345 (14.3%) | |
| 2+ | 382 (41.0%) | 2452 (41.5%) | 145 (38.1%) | 970 (40.3%) | |
| Prior Anti-TNF | 314 (33.7%) | 2184 (37.0%) | 43 (11.3%) | 264 (11.0%) | |
| Prior Methotrexate | 815 (87.4%) | 5005 (84.7%) | 10 (2.6%) | 96 (4.0%) | |
| Prior Thiopurines | -- | -- | 99 (26.0%) | 529 (22.0%) | |
| Prior Abatacept | 35 (3.8%) | 298 (5.0%) | -- | -- | |
| Prior Rituximab | 17 (1.8%) | 152 (2.6%) | -- | -- | |
| History of Actinic Keratotsis | 615 (66.0%) | 3128 (52.9%) | 249 (65.4%) | 1330 (55.3%) | |
| Dermatology encounters in past year | Mean (SD) | 1.7 (1.7) | 1.4 (1.5) | 1.8 (1.6) | 1.6 (1.8) |