Table 1.
Demographic and clinical characteristics
| Characteristics | Monotherapy | Combination therapy | ||||
|---|---|---|---|---|---|---|
| Reached 80 mg/day Dose (N = 16,217) | Did not reach 80 mg/day Dose (N = 19,859) | P‐value* | Reached 80 mg/day Dose (N = 1206) | Did not reach 80 mg/day Dose (N = 342) | P‐value* | |
| Demographic characteristics | ||||||
| Age at index, mean (SD) | 34.2 (12.8) | 32.1 (12.4) | <0.0001 | 36.2 (13.6) | 35.0 (13.6) | 0.1163 |
| Age group, N (%) | – | – | – | – | – | – |
| 18–24 | 5567 (34.3) | 8192 (41.3) | – | 371 (30.8) | 117 (34.2) | – |
| 25–44 | 6618 (40.8) | 7773 (39.1) | – | 447 (37.1) | 129 (37.7) | – |
| 45+ | 4032 (24.9) | 3894 (19.6) | – | 388 (32.2) | 96 (28.1) | – |
| Gender, N (%) | – | – | <0.0001 | – | – | 0.6684 |
| Male | 8682 (53.5) | 9877 (49.7) | – | 626 (51.9) | 173 (50.6) | – |
| Female | 7535 (46.5) | 9982 (50.3) | – | 580 (48.1) | 169 (49.4) | – |
| Clinical characteristics | ||||||
| Predominant ADHD subtype†, N (%) | – | – | 0.0002 | – | – | 0.9504 |
| Inattentive | 8373 (51.6) | 10,650 (53.6) | – | 501 (41.5) | 141 (41.2) | – |
| Hyperactive‐impulsive or combined | 7844 (48.4) | 9209 (46.4) | – | 705 (58.5) | 201 (58.8) | – |
| Proxied prescriber specialty‡, N (%) | – | – | <0.0001 | – | – | 0.8478 |
| Primary care | 9436 (60.6) | 12,656 (66.0) | – | 476 (41.4) | 134 (41.1) | – |
| Psychiatry | 4010 (25.8) | 4059 (21.2) | – | 486 (42.2) | 144 (44.2) | – |
| Neurology | 158 (1.0) | 287 (1.5) | – | 19 (1.7) | 4 (1.2) | – |
| Other | 1956 (12.6) | 2184 (11.4) | – | 170 (14.8) | 44 (13.5) | – |
| Preindex ADHD medication use§, N (%) | 4407 (27.2) | 5709 (28.8) | 0.0010 | 927 (76.9) | 259 (75.7) | 0.6645 |
| Long‐acting stimulants | 2174 (13.4) | 2806 (14.1) | 0.0478 | 469 (38.9) | 134 (39.2) | 0.9499 |
| Intermediate‐acting stimulants | 1573 (9.7) | 2109 (10.6) | 0.0041 | 339 (28.1) | 90 (26.3) | 0.5384 |
| Short‐acting stimulants | 610 (3.8) | 800 (4.0) | 0.1994 | 179 (14.8) | 44 (12.9) | 0.3839 |
| Prodrug stimulants | 964 (5.9) | 1114 (5.6) | 0.1802 | 219 (18.2) | 49 (14.3) | 0.1055 |
| Alpha‐2 adrenergic agonists | 269 (1.7) | 331 (1.7) | 0.9670 | 135 (11.2) | 34 (9.9) | 0.5565 |
| Preindex comorbidities N (%) | 11,039 (68.1) | 12,767 (64.3) | <0.0001 | 946 (78.4) | 240 (70.2) | 0.0018 |
| Anxiety | 4346 (26.8) | 5100 (25.7) | 0.0166 | 393 (32.6) | 93 (27.2) | 0.0645 |
| Bipolar/mania disorders | 1476 (9.1) | 1454 (7.3) | <0.0001 | 162 (13.4) | 41 (12.0) | 0.5259 |
| Conduct disturbance | 149 (0.9) | 196 (1.0) | 0.5146 | 21 (1.7) | 4 (1.2) | 0.6281 |
| Depression | 5351 (33.0) | 5916 (29.8) | <0.0001 | 498 (41.3) | 117 (34.2) | 0.0205 |
| Diabetes | 689 (4.3) | 687 (3.5) | 0.0001 | 62 (5.1) | 15 (4.4) | 0.6729 |
| Eating disorders | 155 (1.0) | 186 (0.9) | 0.8697 | 12 (1.0) | 4 (1.2) | 0.7638 |
| Gastrointestinal disorders | 3307 (20.4) | 4060 (20.4) | 0.9060 | 274 (22.7) | 70 (20.5) | 0.4177 |
| Hypertension | 2827 (17.4) | 2708 (13.6) | <0.0001 | 241 (20.0) | 53 (15.5) | 0.0722 |
| Oppositional Defiance Disorder | 61 (0.4) | 67 (0.3) | 0.5350 | 4 (0.3) | 2 (0.6) | 0.6190 |
| Personality disorders | 233 (1.4) | 236 (1.2) | 0.0398 | 30 (2.5) | 9 (2.6) | 0.8462 |
| Pervasive developmental disorders | 143 (0.9) | 100 (0.5) | <0.0001 | 33 (2.7) | 6 (1.8) | 0.4333 |
| Psychotic disorders | 356 (2.2) | 393 (2.0) | 0.1584 | 30 (2.5) | 3 (0.9) | 0.0875 |
| Sleep disorders | 2487 (15.3) | 2764 (13.9) | 0.0002 | 240 (19.9) | 51 (14.9) | 0.0413 |
| Substance abuse/dependence | 2216 (13.7) | 2630 (13.2) | 0.2445 | 174 (14.4) | 37 (10.8) | 0.0902 |
| Tics/Tourette's | 62 (0.4) | 88 (0.4) | 0.4110 | 17 (1.4) | 2 (0.6) | 0.2776 |
ADHD, attention‐deficit/hyperactivity disorder; SD, standard deviation. *Wilcoxon rank‐sum test (age); Chi‐square test (proxied prescriber specialty); Fishers Exact test (gender, predominate ADHD subtype, preindex ADHD medication use, preindex comorbidities). †Inattentive defined as ≥1 claims with ICD‐9 314.00 without any claims with ICD‐9 314.01; hyperactive‐impulsive or combined defined as ≥1 claim with ICD‐9 314.01. ‡Prescription claims do not list provider specialty; proxies from provider specialty on the office visit on index or in the 6 months preindex that fell closest to index. Prescriber specialty was a missing variable for 657 and 673 monotherapy and 55 and 16 combination therapy patients in the reached 80 mg/day and did not reach 80 mg/day cohorts, respectively. §Patients could have used more than one ADHD medication class in the 6 months preindex.