Regional Supply of Chiropractic Care and Visits to Primary Care Physicians for Back and Neck Pain.

Background: Whether availability of chiropractic care affects use of primary care physician (PCP) services is unknown.

Methods: We performed a cross-sectional study of 17.7 million older adults who were enrolled in Medicare from 2010 to 2011. We examined the relationship between regional supply of chiropractic care and PCP services using Spearman correlation. Generalized linear models were used to examine the association between regional supply of chiropractic care and number of annual visits to PCPs for back and/or neck pain.

Results: We found a positive association between regional supply of chiropractic care and PCP services (rs = 0.52; P <.001). An inverse association between supply of chiropractic care and the number of annual visits to PCPs for back and/or neck pain was apparent. The number of PCP visits for back and/or neck pain was 8% lower (rate ratio, 0.92; 95% confidence interval, 0.91-0.92) in the quintile with the highest supply of chiropractic care compared to the lowest quintile. We estimate chiropractic care is associated with a reduction of 0.37 million visits to PCPs nationally, at a cost of $83.5 million.

Conclusions: Greater availability of chiropractic care in some areas may be offsetting PCP services for back and/or neck pain among older adults.