Table 1 Baseline characteristics after matching for JIA and ADHD groups
Characteristic | <  18 years | ≥ 18 years | ||||||
|---|---|---|---|---|---|---|---|---|
MarketScan | PharMetrics | MarketScan | PharMetrics | |||||
JIA (N = 8633) | ADHD (N = 38,967) | JIA (N = 9155) | ADHD (N = 41,264) | JIA (N = 5789) | ADHD (N = 27,288) | JIA (N = 5638) | ADHD (N = 27,106) | |
Female | 6173 (71.5) | 26,933 (69.1) | 6587 (71.9) | 28,694 (69.5) | 4506 (77.8) | 21,096 (77.3) | 4315 (76.5) | 20,590 (76.0) |
Age, mean (SD) | 10.6 (4.5) | 11.1 (3.9) | 10.5 (4.5) | 11.0 (3.9) | 37.0 (16.5) | 36.2 (15.4) | 34.6 (14.7) | 34.4 (14.3) |
Medications | ||||||||
 bDMARD | 1287 (14.9) | 9 (<  0.1) | 1485 (16.2) | 9 (<  0.1) | 1593 (27.5) | 121 (0.4) | 1614 (28.6) | 129 (0.5) |
 Non-bDMARD | 2512 (29.1) | 529 (1.4) | 3127 (34.2) | 534 (1.3) | 2143 (37.0) | 870 (3.2) | 2266 (40.2) | 845 (3.1) |
 Corticosteroidsa | 2984 (34.6) | 7500 (19.2) | 3367 (36.8) | 4696 (11.4) | 2681 (46.3) | 7845 (28.7) | 2712 (48.1) | 8496 (31.3) |
 NSAIDs | 4090 (47.4) | 3037 (7.8) | 4812 (52.6) | 9868 (23.9) | 2528 (43.7) | 7391 (27.1) | 2634 (46.7) | 8101 (29.9) |
Comorbidities | ||||||||
 Multiple sclerosis | 1 (<  0.1) | 11 (<  0.1) | 1 (<  0.1) | 8 (<  0.1) | 20 (0.3) | 87 (0.3) | 19 (0.3) | 65 (0.2) |
 Asthma | 777 (9.0) | 4130 (10.6) | 887 (9.7) | 5410 (13.1) | 472 (8.2) | 2279 (8.4) | 486 (8.6) | 2565 (9.5) |
 Anxiety | 295 (3.4) | 6123 (15.7) | 317 (3.5) | 7665 (18.6) | 555 (9.6) | 8098 (29.7) | 549 (9.7) | 9185 (33.9) |
 Depression | 208 (2.4) | 4478 (11.5) | 214 (2.3) | 5293 (12.8) | 653 (11.3) | 9469 (34.7) | 622 (11.0) | 9868 (36.4) |
 Diabetes mellitus | 92 (1.1) | 240 (0.6) | 84 (0.9) | 259 (0.6) | 440 (7.6) | 1408 (5.2) | 371 (6.6) | 1146 (4.2) |
 Anemia | 498 (5.8) | 540 (1.4) | 479 (5.2) | 741 (1.8) | 948 (16.4) | 1762 (6.5) | 655 (11.6) | 1674 (6.2) |
 Hypertension | 2 (<  0.1) | 11 (<  0.1) | 6 (0.1) | 9 (<  0.1) | 103 (1.8) | 268 (1.0) | 103 (1.8) | 319 (1.2) |
 Hyperlipidemia | 174 (2.0) | 987 (2.5) | 202 (2.2) | 1388 (3.4) | 1162 (20.1) | 5355 (19.6) | 1023 (18.1) | 5264 (19.4) |
 Malignancy | 56 (0.6) | 128 (0.3) | 49 (0.5) | 136 (0.3) | 278 (4.8) | 856 (3.1) | 162 (2.9) | 702 (2.6) |
CCI score, mean (SD) [40] | 2.4 (0.6) | 2.1 (0.4) | 2.4 (0.6) | 2.1 (0.5) | 2.9 (1.0) | 2.3 (0.7) | 2.8 (0.9) | 2.2 (0.7) |
Autoimmune diseasesb | ||||||||
 0 | 4988 (57.8) | 37,675 (96.7) | 5194 (56.7) | 39,680 (96.2) | 1973 (34.1) | 24,792 (90.9) | 2029 (36.0) | 24,739 (91.3) |
 1 | 2830 (32.8) | 1220 (3.1) | 3075 (33.6) | 1510 (3.7) | 2749 (47.5) | 2160 (7.9) | 2641 (46.8) | 2052 (7.6) |
 2 | 659 (7.6) | 63 (0.2) | 745 (8.1) | 67 (0.2) | 796 (13.8) | 283 (1.0) | 722 (12.8) | 261 (1.0) |
 3 | 127 (1.5) | 8 (<  0.1) | 121 (1.3) | 7 (<  0.1) | 190 (3.3) | 42 (0.2) | 190 (3.4) | 42 (0.2) |
  > 3 | 29 (0.3) | 1 (<  0.1) | 20 (0.2) | 0 (0.0) | 81 (1.4) | 11 (<  0.1) | 56 (1.0) | 12 (<  0.1) |
Healthcare encountersc | ||||||||
 0–10 | 4927 (57.1) | 22,969 (58.9) | 3205 (35.0) | 15,400 (37.3) | 2713 (46.9) | 13,157 (48.2) | 1656 (29.4) | 8139 (30.0) |
 11–20 | 2353 (27.3) | 9995 (25.6) | 3352 (36.6) | 14,630 (35.5) | 1567 (27.1) | 7352 (26.9) | 1741 (30.9) | 8371 (30.9) |
 21–30 | 739 (8.6) | 3235 (8.3) | 1393 (15.2) | 5930 (14.4) | 730 (12.6) | 3346 (12.3) | 1008 (17.9) | 4829 (17.8) |
 31–40 | 294 (3.4) | 1318 (3.4) | 604 (6.6) | 2607 (6.3) | 371 (6.4) | 1677 (6.1) | 561 (10.0) | 2655 (9.8) |
 41–50 | 153 (1.8) | 701 (1.8) | 262 (2.9) | 1150 (2.8) | 183 (3.2) | 821 (3.0) | 273 (4.8) | 1295 (4.8) |
  > 50 | 167 (1.9) | 749 (1.9) | 339 (3.7) | 1547 (3.7) | 225 (3.9) | 935 (3.4) | 399 (7.1) | 1817 (6.7) |