Table. Baseline Characteristics.
| Characteristic | No. (%) | |
|---|---|---|
| Control (n = 117 455) | Intervention (n = 121 431) | |
| Site | ||
| A | 6950 (5.9) | 7388 (6.1) |
| B | 96 275 (82.0) | 100 729 (83.0) |
| C | 7846 (6.7) | 7736 (6.4) |
| D | 6384 (5.4) | 5588 (4.6) |
| Age, y | ||
| 18-39 | 21 237 (18.1) | 22 105 (18.2) |
| 40-60 | 45 032 (38.3) | 44 995 (37.1) |
| ≥61 | 51 186 (43.6) | 54 331 (44.7) |
| Sexa | ||
| Women | 67 915 (57.8) | 69 458 (57.2) |
| Men | 49 534 (42.2) | 51 965 (42.8) |
| Race | ||
| American Indian or Alaska Native | 806 (0.7) | 880 (0.7) |
| Asian | 13 311 (11.3) | 13 197 (10.9) |
| Black or African American | 11 919 (10.1) | 11 649 (9.6) |
| Native Hawaiian or other Pacific Islander | 905 (0.8) | 709 (0.6) |
| White | 76 431 (65.1) | 79 142 (65.2) |
| Multiracial or other | 459 (0.4) | 546 (0.4) |
| Unknown or not reported | 13 624 (11.6) | 15 308 (12.6) |
| Ethnicity | ||
| Hispanic or Latino | 17 754 (15.1) | 18 475 (15.2) |
| Not Hispanic or Latino | 19 867 (16.9) | 19 276 (15.9) |
| Not availableb | 79 834 (68.0) | 83 680 (68.9) |
| Modality | ||
| RG | 93 465 (79.6) | 98 970 (81.5) |
| CT | 494 (0.4) | 449 (0.4) |
| MR | 23 496 (20) | 22 012 (18.1) |
| Charlson Comorbidity Index | ||
| 0 | 75 106 (63.9) | 77 973 (64.2) |
| 1 | 20 675 (17.6) | 21 193 (17.5) |
| 2 | 11 451 (9.7) | 11 760 (9.7) |
| ≥3 | 10 223 (8.7) | 10 505 (8.7) |
| Finding status | ||
| None | 27 770 (23.6) | 27 776 (22.9) |
| LIRE finding without clinically important finding | 72 127 (61.4) | 77 065 (63.5) |
| Clinically important finding | 17 558 (14.9) | 16 590 (13.7) |
| ≥1 Opioid prescriptions prior to index | 32 225 (27.4) | 29 306 (24.1) |
| Primary insurance at index | ||
| Medicare | 44 362 (37.8) | 46 479 (38.3) |
| Medicaid or state-subsidized | 5546 (4.7) | 6510 (5.4) |
| Commercial | 65 375 (55.7) | 66 368 (54.7) |
| VA | 117 (0.1) | 131 (0.1) |
| Self-pay | 731 (0.6) | 570 (0.5) |
| Unknown or not reported | 1324 (1.1) | 1373 (1.1) |
| Socioeconomic index, mean (SD)c | 57 (6) | 57 (7) |
| Health care professional type | ||
| MD | 105 359 (89.7) | 108 165 (89.1) |
| DO | 8131 (6.9) | 9157 (7.5) |
| Extender, eg, NP, PA | 3965 (3.4) | 4109 (3.4) |
| Health care professional specialty | ||
| Family medicine | 56 795 (48.4) | 60 277 (49.6) |
| Internal medicine | 59 684 (50.8) | 60 158 (49.5) |
| Other | 976 (0.8) | 996 (0.8) |
| Female health care professional | 62 840 (53.5) | 62 680 (51.6) |
| Health care professional age, mean (SD), yd | 49 (9) | 49 (9) |
Abbreviations: CT, computed tomography; DO, doctor of osteopathy; MD, medical doctor; LIRE, Lumbar Imaging with Reporting of Epidemiology; MR, magnetic resonance; NP, nurse practitioner; PA, physician’s assistant; RG, radiograph; VA, Veterans Administration.
Does not include 14 patients (<0.1%) with other or unknown gender.
Due to the manner in which race and ethnicity are collected at 1 health system (ie, sometimes the concepts are conflated and sometimes Hispanic ethnicity is captured by a single checkbox), it is not possible to reliably distinguish between “not Hispanic” and “did not answer.”
Does not include 6810 patients (2.7%) with unknown socioeconomic index. Sites mapped participant addresses to Federal Information Processing System codes at the block-group level using geocoding software. These codes were mapped to socioeconomic indices derived from data available from the 2010 Census Summary File 1 and the American Community Survey, 2007 to 2011, 5-year estimate data.
Does not include 424 patients (0.1%) for whom provider age was unknown.