Table 1.
Baseline characteristics, healthcare resource utilization, and all-cause healthcare costs evaluated 6 months prior to the index date
| Variables | Matched populationa | ||||
|---|---|---|---|---|---|
| TRD cohort | Non-TRD MDD cohort | Std. diff.b (%) | Non-MDD control cohort | Std. diff.b (%) | |
| N = 1582 | N = 1582 | N = 1582 | |||
| Age at index date, years | 45.6 ± 16.6 [45] | 45.4 ± 16.7 [44] | 0.7 | 44.9 ± 16.8 [44] | 4.1 |
| Female | 1052 (66.5) | 1067 (67.4) | 2.0 | 1088 (68.8) | 5.0 |
| Race | |||||
| White | 1345 (85.0) | 1339 (84.6) | 1.1 | 1313 (83.0) | 5.4 |
| Black | 68 (4.3) | 69 (4.4) | 0.3 | 58 (3.7) | 3.2 |
| Asian | 16 (1.0) | 15 (0.9) | 0.6 | 15 (0.9) | 0.6 |
| Hispanic | 51 (3.2) | 68 (4.3) | 5.7 | 76 (4.8) | 8.1 |
| Other/unknown | 102 (6.4) | 91 (5.8) | 2.9 | 120 (7.6) | 4.5 |
| Year of index datec | |||||
| 2011 | 215 (13.6) | 203 (12.8) | 2.2 | 224 (14.2) | 1.6 |
| 2012 | 266 (16.8) | 256 (16.2) | 1.7 | 273 (17.3) | 1.2 |
| 2013 | 260 (16.4) | 262 (16.6) | 0.3 | 286 (18.1) | 4.4 |
| 2014 | 250 (15.8) | 243 (15.4) | 1.2 | 259 (16.4) | 1.6 |
| 2015 | 292 (18.5) | 294 (18.6) | 0.3 | 291 (18.4) | 0.2 |
| 2016 | 246 (15.5) | 274 (17.3) | 4.8 | 249 (15.7) | 0.5 |
| 2017 | 53 (3.4) | 50 (3.2) | 1.1 | 0 (0.0) | 25.9 |
| Geographical regiond | |||||
| Northeast | 160 (10.1) | 163 (10.3) | 0.6 | 163 (10.3) | 0.6 |
| Midwest | 792 (50.1) | 768 (48.5) | 3.0 | 807 (51.0) | 1.9 |
| South | 396 (25.0) | 419 (26.5) | 3.3 | 378 (23.9) | 2.6 |
| West | 191 (12.1) | 178 (11.3) | 2.6 | 185 (11.7) | 1.2 |
| Unknown | 43 (2.7) | 54 (3.4) | 4.0 | 49 (3.1) | 2.3 |
| Type of healthcare plan | |||||
| Medicare | 283 (17.9) | 259 (16.4) | 4.0 | 254 (16.1) | 4.9 |
| Commercial | 1299 (82.1) | 1323 (83.6) | 4.1 | 1328 (83.9) | 5.0 |
| Preferred provider organization | 78 (4.9) | 85 (5.4) | 2.0 | 84 (5.3) | 1.7 |
| Point of service plan | 907 (57.3) | 908 (57.4) | 0.1 | 955 (60.4) | 6.3 |
| Health management organization | 189 (11.9) | 187 (11.8) | 0.4 | 176 (11.1) | 2.6 |
| Exclusive provider organization | 84 (5.3) | 93 (5.9) | 2.5 | 71 (4.5) | 3.8 |
| Other healthcare plan | 41 (2.6) | 50 (3.2) | 3.4 | 42 (2.7) | 0.4 |
| Quan-CCI [29] | 0.6 ± 1.3 [0] | 0.5 ± 1.1 [0] | 12.1 | 0.3 ± 0.9 [0] | 29.0 |
| Number of unique mental health diagnoses | 1.2 ± 1.6 [1] | 0.9 ± 1.3 [0] | 20.8 | 0.2 ± 0.5 [1] | 84.3 |
| Other mental health-related medication use [42, 43]e | 614 (38.8) | 343 (21.7) | 35.2 | 152 (9.6) | 62.4 |
| Top five most frequent physical comorbidities [44]f | |||||
| Hypertension | 405 (25.6) | 338 (21.4) | 9.9 | 243 (15.4) | 24.6 |
| Diabetes | 196 (12.4) | 147 (9.3) | 9.9 | 92 (5.8) | 22.5 |
| Chronic pulmonary disease | 167 (10.6) | 157 (9.9) | 2.1 | 94 (5.9) | 16.6 |
| Obesity | 127 (8.0) | 128 (8.1) | 0.2 | 78 (4.9) | 12.5 |
| Hypothyroidism | 140 (8.8) | 121 (7.6) | 4.4 | 100 (6.3) | 9.5 |
| Top five most frequent mental comorbiditiesg | |||||
| Depressionh | 556 (35.1) | 478 (30.2) | 10.3 | 37 (2.3) | 76.7 |
| Anxiety disorders | 345 (21.8) | 245 (15.5) | 15.9 | 70 (4.4) | 49.1 |
| Sleep–wake disorders | 220 (13.9) | 154 (9.7) | 12.8 | 65 (4.1) | 33.3 |
| Substance-related and addictive disorders | 188 (11.9) | 116 (7.3) | 15.3 | 55 (3.5) | 30.9 |
| Other conditions that may be a focus of clinical attention | 121 (7.6) | 110 (7.0) | 2.7 | 65 (4.1) | 14.9 |
| Had ≥ 1 healthcare visit/service | |||||
| Inpatient | 217 (13.7) | 144 (9.1) | 14.3 | 57 (3.6) | 35.0 |
| ED | 203 (12.8) | 178 (11.3) | 4.8 | 112 (7.1) | 18.9 |
| Outpatient | 1398 (88.4) | 1342 (84.8) | 9.8 | 1180 (74.6) | 30.3 |
| Other | 366 (23.1) | 306 (19.3) | 9.2 | 193 (12.2) | 27.8 |
| All-cause healthcare costs ($US, year 2017 values) | 21,872 ± 61,869 [4937] | 13,696 ± 44,271 [2643] | 15.2 | 7160 ± 24,755 [1350] | 31.2 |
| Medical costs | 19,802 ± 60,601 [3363] | 12,357 ± 43,421 [1740] | 14.1 | 5918 ± 23,754 [868] | 30.2 |
| Pharmacy costs | 2070 ± 6719 [420] | 1339 ± 4201 [230] | 13.0 | 1242 ± 5943 [105] | 13.1 |
Data are presented as n (%) or mean ± standard deviation [median] unless otherwise indicated
ED emergency department, ICD-x-CM International Classification of Diseases, xth edition, Clinical Modification, MDD major depressive disorder, Quan-CCI Quan-Charlson comorbidity index, SD standard deviation, Std. diff. standardized difference, TRD treatment-resistant depression
aPatients were matched on propensity score (the probability of being in the TRD cohort vs. the non-TRD MDD or non-MDD cohort), modelled using a logistic regression model adjusted for categorical age, sex, race, year of the index date, geographical region, and type of healthcare plan
bFor continuous variables, the std. diff. was calculated by dividing the absolute difference in means of the control and the TRD cohorts by the pooled SD of both groups. The pooled SD is the square root of the average of the squared SDs. For dichotomous variables, the std. diff. was calculated using the following equation, where P is the respective proportion of participants in each group: (PTRD − Pcontrol)/√[(PTRD(1 − PTRD) + Pcontrol(1 − Pcontrol))/2]
cFor TRD and non-TRD MDD patients, the index date was defined as the date of the first prescription fill for an antidepressant. For non-MDD patients, the index date was randomly generated
dBased on US census regions (http://www2.census.gov/geo/pdfs/maps-data/maps/reference/us_regdiv.pdf)
eIncludes anxiolytics, anticonvulsants/mood stabilizers, antipsychotics, psychostimulants, thyroid hormone (T3), and lithium. Agents were grouped according to their generic name
fThe top five most frequent Elixhauser comorbidities identified in the TRD cohort were reported
gThe top five most frequent mental disorders identified in the TRD cohort were reported
hDepression diagnoses included the following diagnoses ICD-9-CM: 296.2x (MDD—single episode), 296.3x (MDD—recurrent episode), 300.4x (dysthymic disorder), 309.0x (adjustment disorder with depressed mood), 309.1x (prolonged depressive reaction), and 311.x (depressive disorder, not elsewhere classified) or ICD-10-CM: F32x (MDD—single episode), F33x (MDD—recurrent episode), F341 (dysthymic disorder) and F4321 (adjustment disorder with depressed mood). All patients had to have a diagnosis of MDD during the study period, but only a portion had an MDD diagnosis during the baseline period