Table 1. Cohort Characteristics.
Characteristic | Back Pain Visits | Headache Visits | Headache Visits Seen by Clinicians Who Also Saw Back Pain |
---|---|---|---|
Primary care physicians, No. | 57 859 | 52 876 | 34 190 |
Visits per primary care physician, median (IQR) | 7 (4-13) | 7 (4-13) | 9 (5-17) |
Ownership of imaging (% of primary care physicians) | 26.6 | 4.4 | 5.4 |
Uncomplicated clinical visits, No. | 534 559 | 492 804 | 405 721 |
Unique patients seen, No. | 478 640 | 417 010 | 344 991 |
Images ordered (% of visits) | 13.3 | 7.5 | 7.6 |
Chiropractors, No. | 27 583 | NA | NA |
Visits per chiropractor, median (IQR) | 10 (5-19) | NA | NA |
Ownership of imaging (% of chiropractors) | 53.1 | NA | NA |
Uncomplicated clinical visits, No. | 366 529 | NA | NA |
Unique patients seen, No. | 306 507 | NA | NA |
Images ordered (% of visits) | 17.0 | NA | NA |
Specialist physicians, No.a | 15 535 | NA | NA |
Visits per specialist, median (IQR) | 5 (3-9) | NA | NA |
Ownership of imaging (% of specialists) | 41.3 | NA | NA |
Uncomplicated clinical visits, No. | 106 304 | NA | NA |
Unique patients seen, No. | 93 573 | NA | NA |
Images ordered (% of visits) | 36.5 | NA | NA |
Patient age distribution (% of visits), y | |||
18-25 | 7.7 | 10.0 | 10.1 |
26-35 | 19.5 | 21.4 | 22.1 |
36-45 | 25.8 | 26.8 | 27.2 |
46-55 | 27.8 | 25.9 | 25.6 |
56-64 | 19.2 | 15.9 | 15.1 |
Female, % | 53.9 | 70.2 | 69.3 |
Low neighborhood education level, %b | 17.2 | 19.1 | 20.0 |
High neighborhood poverty level, %c | 27.6 | 28.9 | 29.6 |
White race/ethnicity, % | 72.8 | 67.8 | 66.2 |
Census region, % | |||
West | 17.8 | 15.8 | 15.6 |
South | 45.2 | 51.3 | 54.3 |
Midwest | 29.0 | 23.5 | 23.7 |
Northeast | 8.0 | 9.3 | 6.5 |
Abbreviations: IQR, interquartile range; NA, not applicable.
The most common specialties (accounting for two-thirds of all specialist visits) were orthopedic surgery, neurosurgery, back and spine surgery, physical medicine, and rheumatology.
Low neighborhood education was defined as census block groups in which more than 25% of residents had education levels below high school.
High neighborhood poverty was defined as census block groups in which more than 10% of residents had incomes below the poverty level.