Table 1.
Baseline Demographic and Clinical Characteristics
| Matched Sample | ||||||
|---|---|---|---|---|---|---|
| Prevalent Population | Incident Population | |||||
| Switchers | Continuers | Standardized Difference | Switchers | Continuers | Standardized Difference | |
| N=1109 | N=3327 | N=571 | N=1713 | |||
| Age in years, mean ± SD [median] | 57.3 ± 16.3 [60.0] | 56.9 ± 16.3 [60.0] | 2.1% | 56.5 ± 15.7 [57.0] | 55.9 ± 15.4 [57.0] | 4.2% |
| Female, n (%) | 724 (65.3%) | 2198 (66.1%) | 1.6% | 380 (66.5%) | 1162 (67.8%) | 2.7% |
| Year of index date, n (%) | ||||||
| 2016 | 8 (0.7%) | 24 (0.7%) | 0.0% | 4 (0.7%) | 12 (0.7%) | 0.0% |
| 2017 | 408 (36.8%) | 1249 (37.5%) | 1.6% | 169 (29.6%) | 563 (32.9%) | 7.1% |
| 2018 | 456 (41.1%) | 1410 (42.4%) | 2.6% | 274 (48.0%) | 810 (47.3%) | 1.4% |
| 2019 | 237 (21.4%) | 644 (19.4%) | 5.0% | 124 (21.7%) | 328 (19.1%) | 6.4% |
| US region, n (%) | ||||||
| South | 309 (27.9%) | 979 (29.4%) | 3.5% | 142 (24.9%) | 428 (25.0%) | 0.3% |
| Midwest | 446 (40.2%) | 1269 (38.1%) | 4.3% | 245 (42.9%) | 713 (41.6%) | 2.6% |
| Northeast | 101 (9.1%) | 324 (9.7%) | 2.2% | 51 (8.9%) | 157 (9.2%) | 0.8% |
| West | 244 (22.0%) | 743 (22.3%) | 0.8% | 132 (23.1%) | 414 (24.2%) | 2.5% |
| Unknown | 9 (0.8%) | 12 (0.4%) | 5.9% | 1 (0.2%) | 1 (0.1%) | 3.4% |
| Type of insurance plan, n (%) | ||||||
| Commercial | 474 (42.7%) | 1422 (42.7%) | 0.0% | 246 (43.1%) | 722 (42.1%) | 1.9% |
| Medicare | 453 (40.8%) | 1385 (41.6%) | 1.6% | 220 (38.5%) | 673 (39.3%) | 1.6% |
| Medicaid | 149 (13.4%) | 424 (12.7%) | 2.1% | 92 (16.1%) | 272 (15.9%) | 0.6% |
| Other | 33 (3.0%) | 96 (2.9%) | 0.5% | 13 (2.3%) | 46 (2.7%) | 2.6% |
| Specialty of physician prescribing IFX at index date, n (%) | ||||||
| Rheumatology | 488 (44.0%) | 1494 (44.9%) | 1.8% | 243 (42.6%) | 750 (43.8%) | 2.5% |
| Gastroenterology | 301 (27.1%) | 906 (27.2%) | 0.2% | 158 (27.7%) | 474 (27.7%) | 0.0% |
| Infectious diseases | 12 (1.1%) | 55 (1.7%) | 4.9% | 10 (1.8%) | 38 (2.2%) | 3.3% |
| Hematology/oncology | 55 (5.0%) | 122 (3.7%) | 6.4% | 32 (5.6%) | 67 (3.9%) | 8.0% |
| Oncology medical | 20 (1.8%) | 26 (0.8%) | 9.1% | 10 (1.8%) | 13 (0.8%) | 8.9% |
| Other/unknown | 233 (21.0%) | 724 (21.8%) | 1.8% | 118 (20.7%) | 371 (21.7%) | 2.4% |
| Prior history of CID, n (%) | ||||||
| RA | 464 (41.8%) | 1392 (41.8%) | 0.0% | 220 (38.5%) | 660 (38.5%) | 0.0% |
| PsA | 151 (13.6%) | 446 (13.4%) | 0.6% | 86 (15.1%) | 272 (15.9%) | 2.3% |
| PsO | 87 (7.8%) | 262 (7.9%) | 0.1% | 49 (8.6%) | 156 (9.1%) | 1.9% |
| AS | 77 (6.9%) | 226 (6.8%) | 0.6% | 47 (8.2%) | 149 (8.7%) | 1.7% |
| IBD | 523 (47.2%) | 1569 (47.2%) | 0.0% | 271 (47.5%) | 813 (47.5%) | 0.0% |
| CD | 382 (34.4%) | 1141 (34.3%) | 0.3% | 200 (35.0%) | 596 (34.8%) | 0.5% |
| UC | 202 (18.2%) | 587 (17.6%) | 1.5% | 107 (18.7%) | 311 (18.2%) | 1.5% |
| Quan-CCI, mean ± SD [median] | 1.09 ± 1.30 [1.00] | 1.09 ± 1.29 [1.00] | 0.2% | 1.10 ± 1.36 [1.00] | 1.06 ± 1.27 [1.00] | 2.8% |
| Baseline drug use, n (%) | ||||||
| Antidepressants | 429 (38.7%) | 1283 (38.6%) | 0.3% | 242 (42.4%) | 747 (43.6%) | 2.5% |
| NSAIDs | 310 (28.0%) | 947 (28.5%) | 1.1% | 163 (28.5%) | 573 (33.5%) | 10.6% |
| Corticosteroids | 676 (61.0%) | 1998 (60.1%) | 1.8% | 379 (66.4%) | 1108 (64.7%) | 3.6% |
| Biologics | 1109 (100.0%) | 3327 (100.0%) | 0.0% | 571 (100.0%) | 1713 (100.0%) | 0.0% |
| PDE4 inhibitors | 3 (0.3%) | 12 (0.4%) | 1.6% | 2 (0.4%) | 9 (0.5%) | 2.7% |
| Opioids | 573 (51.7%) | 1702 (51.2%) | 1.0% | 311 (54.5%) | 961 (56.1%) | 3.3% |
| Non-narcotic analgesics | 51 (4.6%) | 177 (5.3%) | 3.3% | 28 (4.9%) | 85 (5.0%) | 0.3% |
| DMARDs | 641 (57.8%) | 1962 (59.0%) | 2.4% | 343 (60.1%) | 1082 (63.2%) | 6.4% |
| Duration of treatment with originator IFX prior to index date days mean ± SD [median] | ≥1073 ± 619 [991] | ≥1035 ± 671 [893] | 6.0% | 762 ± 443 [628] | 746 ± 480 [607] | 3.6% |
| Place of service for index claim | ||||||
| Medical | ||||||
| Outpatient | 1006 (90.7%) | 3006 (90.4%) | 1.2% | 516 (90.4%) | 1539 (89.8%) | 1.8% |
| Inpatient | 0 (0.0%) | 0 (0.0%) | - | 0 (0.0%) | 0 (0.0%) | – |
| Emergency room | 2 (0.2%) | 9 (0.3%) | 1.9% | 1 (0.2%) | 4 (0.2%) | 1.3% |
| Other services | 61 (5.5%) | 197 (5.9%) | 1.8% | 37 (6.5%) | 127 (7.4%) | 3.7% |
| Pharmacy | 30 (2.7%) | 84 (2.5%) | 1.1% | 11 (1.9%) | 29 (1.7%) | 1.8% |
| Medical and pharmacy | 10 (0.9%) | 31 (0.9%) | 0.3% | 6 (1.1%) | 14 (0.8%) | 2.4% |
Abbreviations: AS ankylosing spondylitis; CD Crohn’s disease; CID chronic inflammatory disease; DMARD disease modifying anti-rheumatic drug; IBD inflammatory bowel disease; IFX infliximab; NSAID non-steroidal anti-inflammatory drug; PDE4 phosphodiesterase-4; PsA psoriatic arthritis; PsO plaque psoriasis; Quan-CCI Quan-Charlson comorbidity index; RA, rheumatoid arthritis; SD, standard deviation; UC, ulcerative colitis; US, United States.