| Independent Variable | Visits to any PCP for back and/or neck pain | Visits for Back and/or Neck Pain, By PCP Specialty | |
|---|---|---|---|
| Family Medicine PCP | Internal Medicine PCP | ||
| Supply of health services | |||
| Quintile of chiropractic care | |||
| 1 (lowest) | 1.00 (Reference) | 1.00 (Reference) | 1.00 (Reference) |
| 2 | 1.08 (1.07–1.09) | 1.07 (1.06–1.08) | 1.08 (1.07–1.09) |
| 3 | 0.98 (0.97–0.98) | 0.97 (0.96–0.98) | 0.94 (0.93–0.94) |
| 4 | 0.97 (0.97–0.98) | 0.86 (0.86–0.86) | 1.02 (1.01–1.02) |
| 5 (highest) | 0.92 (0.91–0.92) | 0.85 (0.84–0.86) | 0.90 (0.89–0.91) |
| PCP services,† number per 10,000 | 1.00 (1.00–1.00) | 1.02 (1.02–1.02) | 1.01 (1.01–1.01) |
| Patient characteristics | |||
| Age, years | 1.00 (0.99–1.00) | 0.99 (0.99–0.99) | 1.01 (1.00–1.01) |
| Sex | |||
| Male | 1.00 (Reference) | 1.00 (Reference) | 1.00 (Reference) |
| Female | 1.36 (1.35–1.36) | 1.30 (1.30–1.31) | 1.41 (1.40–1.41) |
| Race/ethnicity | |||
| Non-Hispanic white | 1.00 (Reference) | 1.00 (Reference) | 1.00 (Reference) |
| Other | 1.11 (1.10,–1.11) | 1.00 (0.99–1.00) | 1.15 (1.14–1.16) |
| Rurality of residence | |||
| Urban | 1.00 (Reference) | 1.00 (Reference) | 1.00 (Reference) |
| Rural | 0.99 (0.99–0.99) | 1.39 (1.38–1.40) | 0.72 (0.71–0.72) |
| Charlson Comorbidity Score | |||
| 0 | 1.00 (Reference) | 1.00 (Reference) | 1.00 (Reference) |
| 1 | 1.13 (1.12–1.13) | 1.10 (1.09–1.11) | 1.15 (1.14–1.16) |
| 2 | 1.25 (1.25–1.26) | 1.20 (1.19–1.21) | 1.30 (1.30–1.31) |
| ≥3 | 1.29 (1.29–1.30 | 1.22 (1.21–1.24) | 1.35 (1.34–1.35) |
For each of the 3 models, n = 14.9 million Medicare patients.
↵* All rate ratios are highly significant at P <.001 (except for race/ethnicity) in predicting visits to family medicine physicians.
↵† Variable used corresponds to primary care physician (PCP) specialty for the respective model (eg, for prediction of visits to family medicine PCPs, number of family medicine physicians per 10,000 capita was used).