Table 1 Baseline characteristics of the three cohorts
All | Early untreated RA | Prevalent RA, naïve to biologic DMARDs | Prevalent RA, exposed to biologic DMARDs | |
|---|---|---|---|---|
Total number | 195,433 (100) | 78,667 (100) | 93,534 (100) | 23,232 (100) |
Insurance type | ||||
Commercial (United) | 82,402 (42.2) | 26,810 (34.1) | 40,023 (42.8) | 15,569 (67.0) |
Public (Medicaid) | 113,031 (57.8) | 51,857 (65.9) | 53,511 (57.2) | 7663 (33.0) |
Age | 49 (±12.1) | 49 (±12.2) | 50 (±12.1) | 49 (±11.9) |
Gender (female) | 153,933 (78.8) | 60,487 (76.9) | 75,456 (80.7) | 17,990 (77.4) |
Comorbid conditions | ||||
Hyperlipidemia | 76,793 (39.3) | 36,538 (46.4) | 33,005 (35.3) | 7250 (31.2) |
Heart diseasea | 34,869 (17.8) | 17,501 (22.2) | 14,896 (15.9) | 2472 (10.6) |
Hypertension | 92,080 (47.1) | 41,338 (52.5) | 42,244 (45.2) | 8498 (36.6) |
Cerebrovascular accident | 10,118 (5.2) | 5432 (6.9) | 4175 (4.5) | 511 (2.2) |
Diabetes | 41,704 (21.3) | 20,195 (25.7) | 18,143 (19.4) | 3366 (14.5) |
Obesity | 22,828 (11.7) | 12,317 (15.7) | 8829 (9.4) | 1682 (7.2) |
Inflammatory bowel disease | 4037 (2.1) | 1475 (1.9) | 1661 (1.8) | 901 (3.9) |
History of hospitalization with severe infectionsb | 8876 (4.6) | 4539 (5.8) | 3689 (3.9) | 648 (2.8) |
COPD | 62,388 (31.9) | 30,789 (39.1) | 26,974 (28.8) | 4625 (19.9) |
Liver disease | 13,030 (6.7) | 7035 (8.9) | 5057 (5.4) | 938 (4.0) |
Metastatic cancer | 1849 (1.0) | 1028 (1.3) | 719 (0.8) | 102 (0.4) |
Any tumor | 12,976 (6.6) | 6301 (8.0) | 5683 (6.1) | 992 (4.3) |
Alcohol abuse | 8699 (4.5) | 5385 (6.8) | 2928 (3.1) | 386 (1.7) |
Tobacco use | 35,992 (18.4) | 18,567 (23.6) | 14,562 (15.6) | 2863 (12.3) |
Combined comorbidity score | 1 (±2.0) | 2 (±2.0) | 1 (±1.9) | 1 (±1.5) |
History of medication use | ||||
ACE inhibitors | 35,742 (18.3) | 15,088 (19.2) | 17,107 (18.3) | 3547 (15.3) |
ARBs | 16,311 (8.4) | 7159 (9.1) | 7310 (7.8) | 1842 (7.9) |
Beta blockers | 30,934 (15.8) | 12,955 (16.5) | 14,679 (15.7) | 3300 (14.2) |
Calcium channel blockers | 28,302 (14.5) | 11,936 (15.2) | 13,820 (14.8) | 2546 (11.0) |
Diuretics | 52,688 (27.0) | 22,093 (28.1) | 25,279 (27.0) | 5316 (22.9) |
Insulin | 8851 (4.5) | 4100 (5.2) | 3920 (4.2) | 831 (3.6) |
Oral hypoglycemic | 21,004 (10.8) | 95,28 (12.1) | 9620 (10.3) | 1856 (8.0) |
Statins | 38,246 (19.6) | 173,91 (22.1) | 17,079 (18.3) | 3776 (16.3) |
Non-statin lipid-lowering drugs | 11,324 (5.8) | 5213 (6.6) | 4845 (5.2) | 1266 (5.4) |
Aspirins | 10,876 (5.6) | 58,42 (7.4) | 4517 (4.8) | 517 (2.2) |
COX-2 inhibitors | 44,555 (22.8) | 150,28 (19.1) | 24,130 (25.8) | 5397 (23.2) |
Non-selective NSAIDs | 108,196 (55.4) | 468,58 (59.6) | 51,080 (54.6) | 10,258 (44.2) |
Opioids | 118,542 (60.7) | 485,45 (61.7) | 56,545 (60.5) | 13,452 (57.9) |
Steroids | 106,676 (54.6) | 33,474 (42.6) | 57,604 (61.6) | 15,598 (67.1) |
Cumulative steroid dose (mg/day in prior year) | 3 (±32.8) | 2 (±3.2) | 4 (±43.3) | 4 (±20.3) |
Average daily steroid dose | ||||
None | 109, 365 (56.0) | 53,489 (68.0) | 45,373 (48.5) | 10,503 (45.2) |
Low (<5 mg/day) | 66,779 (34.2) | 22,933 (29.2) | 35,157 (37.6) | 8689 (37.4) |
Medium (5–10 mg/day) | 12,610 (6.5) | 1473 (1.9) | 8408 (9.0) | 2729 (11.7) |
High (≥10 mg/day) | 6679 (3.4) | 772 (1.0) | 4596 (4.9) | 1311 (5.6) |
Non-biologic drugs | − | − | 66,961 (71.6) | 16,550 (71.2) |
Number of non-biologic drugs | − | |||
None | − | − | 26,573 (28.4) | 6682 (28.8) |
One | − | − | 48,124 (51.5) | 11,822 (50.9) |
More than one | − | − | 18,837 (20.1) | 4728 (20.4) |
Prior MTX | − | − | 38,172 (40.8) | 12,381 (53.3) |
Prior HCQ | − | − | 28,901 (30.9) | 3735 (16.1) |
Health care utilization | ||||
Number of prescriptions | 14 (±9.6) | 14 (±10.2) | 14 (±9.3) | 13 (±8.2) |
Number of physician visits | 11 (±9.4) | 11 (±9.5) | 11 (±9.4) | 12 (±8.4) |
Number of hospitalizations | 0 (±1.0) | 0 (±1.2) | 0 (±1.0) | 0 (±0.7) |
Number of emergency room visits | 1 (±3.0) | 1 (±3.6) | 1 (±2.7) | 1 (±1.7) |