Table 3. Estimated National Impact of Chiropractic Care on Annual Total Primary Care Physician (PCP) Visits and Expenditures for Back and/or Neck Pain

Quintile of Chiropractic Care Supply	With Chiropractic Care^*		Estimated Difference Without Chiropractic Care^{^†}
Quintile of Chiropractic Care Supply	Visits to PCPs for Back and/or Neck Pain	Expenditures on PCP Visits for Back and/or Neck Pain	Visits to PCPs for Back and/or Neck Pain	Expenditures on PCP Visits for Back and/or Neck Pain
1 (Lowest)	1.21	275.6	Reference	Reference
2	1.07	243.7	−0.14	−31.9
3	1.20	274.6	−0.01	−1.0
4	1.11	252.9	−0.10	−22.7
5 (Highest)	1.09	247.7	−0.12	−27.9
Total			−0.37	−83.5

↵* Estimates are based on predictions from the model adjusted for covariates in Table 2.
↵† Estimated by comparing with quintile 1 (as a measure of very low chiropractic care supply).