The United States Chiropractic Workforce: An alternative or complement to primary care?

We used nationally representative data to estimate the per 100,000 capita supply of chiropractors and primary care physicians according to the 306 predefined Hospital Referral Regions. Multiple variable Poisson regression was used to examine the influence of population characteristics on the supply of both practitioner-types.According to these data, there are 74,623 US chiropractors and the per capita supply of chiropractors varies more than 10-fold across the nation. Chiropractors practice in areas with greater supply of primary care physicians (Pearson’s correlation 0.17, p-value？<？0.001) and appear to be more responsive to market conditions (i.e. more heavily influenced by population characteristics) in regards to practice location than primary care physicians.These findings suggest that chiropractors practice in areas of greater primary care physician supply. Therefore chiropractors may be functioning in more complementary roles to primary care as opposed to an alternative point of access.In the United States (US) health care policymakers continue to be concerned about the ability of the primary care workforce to meet the future primary care needs of an aging and expanding population. Some authorities encourage increasing the general physician workforce to address the shortage [1-3]. However, others argue that, because of market forces, expansion would only perpetuate the overabundance of specialists and continue to widen the divide between high and low supply of primary care physicians [4,5]. Indeed, recent studies suggest that, after accounting for population differences, a 2- to 3-fold variation in physician supply exists across geographic regions [4]. And only primary care physician supply [4] appears to be related to improvements in population health outcomes [6].To meet the nation’s future primary care needs, it might be reasonable to expand the scope of practice of ancillary practitioners such as nurse practitioners and physician assistants. However, ther