Table 2.
Covariate distribution among patients included in each comparison after propensity score weighting, Medicaid data 2000-10 and Optum Clinformatics data 2004-15. Values are numbers (percentages) unless stated otherwise
| Covariates | Patients with autoimmune inflammatory conditions* | Patients with autoimmune inflammatory conditions* other than SLE | Patients with autoimmune inflammatory conditions* other than SLE | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Non-biologics (n=1578) | Steroids (n=2527) | Standardized difference† | TNF inhibitors (n=759) | Steroids (n=1647) | Standardized difference† | TNF inhibitors (n=752) | Non-biologics (n=804) | Standardized difference† | |||
| Demographics | |||||||||||
| Mean (SD) age (years) | 29 (6.1) | 29 (6.1) | −2.4 | 30 (5.4) | 31 (5.6) | −3.3 | 30 (5.5) | 30 (5.5) | 1.7 | ||
| Region: | |||||||||||
| Midwest | 424 (26.9) | 683 (27) | −0.4 | 225 (29.6) | 493 (29.9) | −0.6 | 229 (30.5) | 262 (32.6) | −4.6 | ||
| North east | 273 (17.3) | 434 (17.2) | 0.4 | 102 (13.4) | 220 (13.4) | 0.2 | 102 (13.6) | 91 (11.3) | 6.8 | ||
| South | 578 (36.6) | 912 (36.1) | 1.1 | 278 (36.6) | 590 (35.8) | 1.7 | 267 (35.5) | 269 (33.5) | 4.2 | ||
| West | 303 (19.2) | 498 (19.7) | −1.3 | 154 (20.3) | 344 (20.9) | −1.4 | 154 (20.5) | 181 (22.6) | −5.1 | ||
| Insurance type: | |||||||||||
| Medicaid | 743 (47.1) | 1202 (47.6) | −1 | 194 (25.6) | 420 (25.5) | 0.1 | 193 (25.7) | 196 (24.4) | 3 | ||
| Optum Clinformatics | 835 (52.9) | 1325 (52.4) | 1 | 565 (74.4) | 1227 (74.5) | −0.1 | 559 (74.3) | 608 (75.6) | −3 | ||
| Autoimmune inflammatory condition diagnoses | |||||||||||
| Ankylosing spondilitis | 44 (2.8) | 73 (2.9) | −0.5 | 58 (7.6) | 131 (7.9) | −1.1 | 57 (7.6) | 67 (8.3) | −2.6 | ||
| Psoriatic arthritis | 17 (1.1) | 29 (1.2) | −0.7 | 77 (10.1) | 161 (9.8) | 1.2 | 58 (7.7) | 52 (6.5) | 4.9 | ||
| Rheumatoid arthritis | 495 (31.4) | 829 (32.8) | −3 | 365 (48.1) | 851 (51.7) | −7.2 | 363 (48.3) | 438 (54.5) | −12.5 | ||
| SLE | 925 (58.6) | 1471 (58.2) | 0.8 | 12 (1.6) | 32 (1.9) | −2.7 | 13 (1.7) | 18 (2.2) | −3.3 | ||
| Irritable bowel disease | 295 (18.7) | 480 (19) | −0.8 | 322 (42.4) | 675 (41) | 2.9 | 333 (44.3) | 331 (41.1) | 6.4 | ||
| Other medical conditions and medication use at baseline | |||||||||||
| Anemia | 136 (8.6) | 232 (9.2) | −2 | 45 (5.9) | 80 (4.9) | 4.7 | 45 (6) | 39 (4.8) | 5.2 | ||
| Chronic respiratory conditions | 23 (1.5) | 37 (1.5) | 0 | <11‡ | 24 (1.5) | −5.1 | <11‡ | <11‡ | 1.3 | ||
| Pre-existing diabetes mellitus | 29 (1.8) | 52 (2) | −1.5 | <11‡ | 22 (1.3) | 0.1 | <11‡ | <11‡ | 2.9 | ||
| Drug misuse or dependence | 43 (2.7) | 64 (2.5) | 1.3 | 11 (1.4) | 22 (1.3) | 0.9 | 11 (1.5) | <11‡ | 2.4 | ||
| Renal disease | 77 (4.9) | 147 (5.8) | −4.1 | <11‡ | <11‡ | 2.8 | <11‡ | <11‡ | 2.1 | ||
| Previous infections | 17 (1.1) | 33 (1.3) | −2.1 | <11‡ | <11‡ | −1.4 | <11‡ | <11‡ | −0.8 | ||
| Insulin | 18 (1.1) | 25 (1) | 1.4 | <11‡ | 20 (1.2) | −2.6 | <11‡ | <11‡ | 1.5 | ||
| Oral hypoglycemic drugs | 27 (1.7) | 53 (2.1) | −3 | <11‡ | 17 (1) | 1.3 | <11‡ | 13 (1.6) | −3.3 | ||
| Opioids | 421 (26.7) | 651 (25.8) | 2.1 | 192 (25.3) | 434 (26.4) | −2.4 | 186 (24.7) | 212 (26.4) | −3.8 | ||
| Benzodiazepines | 109 (6.9) | 181 (7.2) | −1 | 67 (8.8) | 153 (9.3) | −1.5 | 63 (8.4) | 70 (8.7) | −1.2 | ||
| Antidepressants | 282 (17.9) | 448 (17.7) | 0.4 | 127 (16.7) | 269 (16.3) | 1.1 | 128 (17) | 153 (19.1) | −5.3 | ||
| Antihypertensive drugs | 183 (11.6) | 293 (11.6) | 0 | 33 (4.3) | 65 (3.9) | 2 | 33 (4.4) | 34 (4.2) | 1.1 | ||
| Healthcare use characteristics | |||||||||||
| Mean (SD) No of distinct prescription drugs | 3 (2.9) | 3 (2.7) | 1.4 | 3 (2.8) | 3 (2.8) | −5.3 | 2 (2.8) | 3 (2.8) | −8.8 | ||
| Mean (SD) No of hospital admission | 0 (0.3) | 0 (0.3) | −0.8 | 0 (0.2) | 0 (0.2) | 1.9 | 0 (0.2) | 0 (0.2) | 3.9 | ||
| Mean (SD) No of outpatient visits | 6 (6.1) | 6 (6.2) | −1.8 | 6 (5.5) | 6 (5.9) | −0.7 | 6 (5.5) | 6 (5.5) | −5.4 | ||
TNF=tumor necrosis factor α; SLE=systemic lupus erythematosus.
Conditions included ankylosing spondylitis, inflammatory bowel disease, psoriatic arthritis, rheumatoid arthritis, and SLE. TNF inhibitors are not indicated for the treatment of SLE and therefore patients with only SLE were excluded from comparisons concerning TNF inhibitors.
Standardized differences ≥10 indicate substantial imbalance in a particular covariate between the two treatment groups. Variables with standardized differences >10 after propensity score weighting were also added to the Cox proportional hazards regression model for risk adjustment.
Actual numbers are suppressed for counts <11 as required by data use agreement with the Centers for Medicare and Medicaid Services.