Table 1.
Patient characteristics of non-biologic disease-modifying anti-rheumatic drug (DMARD) and TNF-α inhibitor groups
| Baseline | Patients remaining in the cohort 6 months post-index | Patients remaining in the cohort 12 months post-index | ||||
|---|---|---|---|---|---|---|
|
| ||||||
| Non-biologic DMARD | TNF-α inhibitor | Non-biologic DMARD | TNF-α inhibitor | Non-biologic DMARD | TNF-α inhibitor | |
| Total n | 2400 | 4822 | 1195 | 3571 | 655 | 2439 |
| Proportion relative to baseline | 100% | 100% | 50% | 74% | 27% | 51% |
| Time-fixed covariates* | ||||||
| Female | 1899 (79) | 3515 (73) | 943 (79) | 2579 (72) | 515 (79) | 1771 (73) |
| Diabetes | 127 (5) | 226 (5) | 58 (5) | 159 (4) | 38 (6) | 103 (4) |
| Hyperlipidemia | 538 (22) | 1096 (23) | 268 (22) | 844 (24) | 153 (23) | 580 (24) |
| Obesity | 114 (5) | 207 (4) | 49 (4) | 153 (4) | 26 (4) | 92 (4) |
| Smoking | 166 (7) | 354 (7) | 77 (6) | 253 (7) | 34 (5) | 157 (6) |
| Combined comorbidity score (mean(SD)) | 0.5 (0.9) | 0.4 (0.8) | 0.5 (0.9) | 0.4 (0.8) | 0.5 (0.9) | 0.4 (0.8) |
| Lipid lowering agents | 162 (7) | 318 (7) | 85 (7) | 247 (7) | 48 (7) | 180 (7) |
| Diabetes medications | 57 (2) | 102 (2) | 28 (2) | 76 (2) | 18 (3) | 46 (2) |
| Time-varying covariates | ||||||
| Age, in years (mean(SD)) | 48 (12) | 46 (11) | 49 (12) | 46 (11) | 50 (11) | 46 (11) |
| Rheumatoid arthritis- related drug usea | ||||||
| NSAIDs | 1163 (48) | 2724 (56) | 538 (45) | 1648 (46) | 294 (45) | 1044 (43) |
| Injectable steroid use | 614 (26) | 1372 (28) | 251 (21) | 870 (24) | 91 (14) | 440 (18) |
| Oral steroid use | 1254 (52) | 2766 (57) | 570 (48) | 1648 (46) | 262 (40) | 825 (34) |
| Cumulative dose of oral steroids among users, in mg prednisone equivalents (mean(SD)) | 861 (1439) | 893 (1206) | 899 (1256) | 699 (725) | 809 (1401) | 653 (662) |
| Leflunomide or cyclosporineb | - | - | 37 (3) | 62 (2) | 33 (5) | 72 (3) |
| Non-TNF biologicsb | - | - | 9 (1) | 64 (2) | 8 (1) | 42 (2) |
| Health care utilization* | ||||||
| Any hospitalization | 115 (5) | 259 (5.4) | 57 (5) | 147 (4) | 46 (7) | 104 (4) |
| Any emergency room visit | 230 (10) | 498 (10) | 107 (9) | 301 (8) | 44 (7) | 194 (8) |
| Number of office visits (mean(SD)) | 5 (3) | 6 (3) | 5 (3) | 5 (3) | 4 (3) | 5 (3) |
| Number of distinct generic prescriptions filled (mean(SD)) | 6 (4) | 7 (4) | 7 (4) | 7 (4) | 7 (4) | 6 (4) |
Abbreviations: DMARDs- disease modifying anti-rheumatic drugs, NSAID- non steroidal anti-inflammatory drug, SD- standard deviation, TNF- tumor necrosis factor.
Numbers in the table are n(%) unless indicated otherwise.
Time fixed-covariates were measured at the index date for everyone. Rheumatoid arthritis related drug use and healthcare utilization variables were reported for 6 months pre-index for Baseline columns, months 1 through 6 post-index for next two columns, and months 7 through 12 post-index for last two columns.
Users of leflunomide or cyclosporine or non-TNF biologics during the pre-index period were not included in the study. Use of these agents was controlled for as time-varying covariates if patients included in our study initiated these agents post-index.