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Access to Chiropractic Care and the Cost of Spine Conditions Among Older Adults
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Access to Chiropractic Care and the Cost of Spine Conditions Among Older Adults

Matthew A. Davis, PhD, DC, MPH; Olga Yakusheva, PhD; Haiyin Liu, MA; Joshua Tootoo, MS; Marita G. Titler, PhD, RN; and Julie P.W. Bynum, MD, MPH
Among older adults who have a spine condition, access to chiropractic care may reduce medical spending on diagnostic services.

Despite a sizable literature devoted to describing health services that function outside of the conventional medical system in the United States, our study is among the first to attempt to quantify the effect of access to such a service on spending using a quasi-experimental approach. We applied state-of-the-art geospatial methods both for developing the geographic accessibility measures and for using relocation as a tool for approximating causal mechanisms in observational studies. Originating from the field of economics, natural experiments are being used by a growing number of health researchers who seek to identify causal mechanisms from nonexperimental data.22-25 Taking advantage of unique opportunities to balance confounding factors and designs that allow for temporal observations to be made offers stronger evidence of cause and effect.26 For instance, in an influential report, Song et al used Medicare patients who relocated to examine variation in practice intensity.24 Although effects of chiropractic care accessibility on spending were inconsistent and overall small, we did find some evidence of chiropractic care accessibility affecting spending on certain types of spine-related care. Specifically, we observed small, consistent differences in spending on diagnostic imaging and tests for spine conditions. This is among the first evidence to suggest a potential reduction in medical service use due to a health service that operates primarily outside of traditional pathways of care.

To our knowledge this is also the first application of the variable-distance enhanced 2-step floating catchment area method to national provider data. This approach has several advantages over other measures, including that it (1) provides a more realistic estimation of impact of moving that incorporates travel time in both the urban and rural settings, (2) allows for movement/interaction across areas to account for accessibility in adjacent locales, and (3) is less sensitive to changes in scale because it uses a continuous measure of impedance to calculate provider to population ratios. Use of this method led us to identify relatively high accessibility of chiropractic care in the upper Midwest and lower accessibility in the South, which aligns with previous reports.21 Although our analyses cannot fully explain this pattern, the profession did originate in the upper Midwest, suggesting that cultural factors may play a role. A recent report that compared availability of different provider types found that chiropractors were more likely to locate in areas of higher income and health status.27

Healthcare Policy Implications

In spite of the Choosing Wisely campaign’s mantra that “less is more” for clinical management of back pain,28,29 trends indicate worrisome increases in the use of opioid analgesic medications, overreliance on medical specialists, and unwarranted diagnostic imaging.30-32 All of these practices lead to higher healthcare costs.3,33-35

Medicare spends $400 million to $500 million on chiropractic care each year,36,37 and chiropractic care has been scrutinized several times by the Office of the Inspector General.12,36-38 A prior study uncovered an association between higher accessibility of chiropractic care and lower reliance on primary care services, suggesting that chiropractic care may substitute for medical care.39 We sought to determine whether or not chiropractic care is merely additive to the system (ie, patients use chiropractic care who would have otherwise not used health services or patients use chiropractic care in addition to other health services). We find that chiropractic care may be associated with small savings in aspects of ambulatory care. Although these are small per-person dollar differences ($40 reduction in annual spending), the cumulative effect could be quite large given the prevalence of spine conditions among older adults. Thus, it is conceivable that CMS is recapturing a portion of the payout for coverage of chiropractic care.


Our study has several potential limitations that must be acknowledged. The cohort consisted of older adult Medicare beneficiaries who relocated once from 2010 to 2014, which could be perceived to limit the generalizability of our findings. However, considering that each beneficiary included in our cohort served as his or her own control, there is no reason to believe that the change in spending is not more broadly generalizable. A particular strength of using Medicare beneficiary relocation as an exogenous change unlikely to be related to our primary variable of interest is that it can be considered a more rigorous study design compared with traditional observational studies. However, we found differences in race and health status according to the change in chiropractic care accessibility. Despite accounting for these differences in our analyses, we cannot completely rule out residual confounding. Lastly, because our study used administrative data, we focused on spending, which is only one aspect of the important issues related to management of back and neck pain. We cannot say whether reductions in pain, improvements in quality of life, or use of pharmacological agents were any different from the data in this study. These are particularly important avenues for investigation in the context of the current opioid crisis and will be addressed in future work.


This study is among the first to examine whether access to chiropractic care, a health service that provides a significant amount of the nation’s conservative management of nonspecific back pain, has any effect on Medicare spending. We found some evidence of a relationship between lower accessibility of chiropractic care and higher spending on diagnostic imaging and testing. Future work is required to determine if indeed access to chiropractic care for Medicare beneficiaries in any way breaks the pathway to care that is discordant with practice guidelines.

Author Affiliations: University of Michigan Institute for Social Research (MAD), Ann Arbor, MI; University of Michigan School of Nursing (MAD, OY, HL, MGT), Ann Arbor, MI; Institute for Healthcare Policy and Innovation, University of Michigan (MAD, OY, MGT, JPWB), Ann Arbor, MI; University of Michigan School of Public Health (OY), Ann Arbor, MI; National Center for Geospatial Medicine, Rice University (JT), Houston, TX; Department of Internal Medicine, Geriatric and Palliative Medicine, University of Michigan Medical School (JPWB), Ann Arbor, MI.

Source of Funding: This work was supported by award number 1R01AT009003 from the National Center for Complementary and Integrative Health at the National Institutes of Health. The views expressed herein do not necessarily represent the official views of the National Center for Complementary and Integrative Health nor the National Institutes of Health.

Author Disclosures: The authors report no relationship or financial interest with any entity that would pose a conflict of interest with the subject matter of this article.

Authorship Information: Concept and design (MAD, OY, MGT, JPWB); acquisition of data (HL); analysis and interpretation of data (MAD, JT, MGT, JPWB); drafting of the manuscript (MAD); critical revision of the manuscript for important intellectual content (MAD, OY, HL, JT, MGT, JPWB); statistical analysis (MAD, OY, JT); provision of patients or study materials (MAD); obtaining funding (MAD); administrative, technical, or logistic support (HL); and supervision (MAD).

Address Correspondence to: Matthew A. Davis, PhD, DC, MPH, University of Michigan, 400 N Ingalls St, Room 4347, Ann Arbor, MI 48109. Email:

1. Martin BI, Deyo RA, Mirza SK, et al. Expenditures and health status among adults with back and neck problems [erratum in JAMA. 2008;299(22):2630]. JAMA. 2008;299(6):656-664. doi: 10.1001/jama.299.6.656.

2. Murray CJ, Atkinson C, Bhalla K, et al; US Burden of Disease Collaborators. The state of US health, 1990-2010: burden of diseases, injuries, and risk factors. JAMA. 2013;310(6):591-608. doi: 10.1001/jama.2013.13805.

3. Deyo RA, Weinstein JN. Low back pain. N Engl J Med. 2001;344(5):363-370. doi: 10.1056/NEJM200102013440508.

4. Docking RE, Fleming J, Brayne C, Zhao J, Macfarlane GJ, Jones GT; Cambridge City Over-75s Cohort Study Collaboration. Epidemiology of back pain in older adults: prevalence and risk factors for back pain onset. Rheumatology (Oxford). 2011;50(9):1645-1653. doi: 10.1093/rheumatology/ker175.

5. Dunn KM, Hestbaek L, Cassidy JD. Low back pain across the life course. Best Pract Res Clin Rheumatol. 2013;27(5):591-600. doi: 10.1016/j.berh.2013.09.007.

6. Hart LG, Deyo RA, Cherkin DC. Physician office visits for low back pain: frequency, clinical evaluation, and treatment patterns from a U.S. national survey. Spine (Phila Pa 1976). 1995;20(1):11-19.

7. Whedon JM, Song Y, Davis MA. Trends in the use and cost of chiropractic spinal manipulation under Medicare Part B. Spine J. 2013;13(11):1449-1454. doi: 10.1016/j.spinee.2013.05.012.

8. Davis MA, Sirovich BE, Weeks WB. Utilization and expenditures on chiropractic care in the United States from 1997 to 2006. Health Serv Res. 2010;45(3):748-761. doi: 10.1111/j.1475-6773.2009.01067.x.

9. Allareddy V, Greene BR, Smith M, Haas M, Liao J. Facilitators and barriers to improving interprofessional referral relationships between primary care physicians and chiropractors. J Ambul Care Manage. 2007;30(4):347-354. doi: 10.1097/01.JAC.0000290404.96907.e3.

10. Greene BR, Smith M, Haas M, Allareddy V. How often are physicians and chiropractors provided with patient information when accepting referrals? J Ambul Care Manage. 2007;30(4):344-346. doi: 10.1097/01.JAC.0000290403.89284.e0.

11. Meeker WC, Haldeman S. Chiropractic: a profession at the crossroads of mainstream and alternative medicine. Ann Intern Med. 2002;136(3):216-227. doi: 10.7326/0003-4819-136-3-200202050-00010.

12. Whedon JM, Goertz CM, Lurie JD, Stason WB. Beyond spinal manipulation: should Medicare expand coverage for chiropractic services? a review and commentary on the challenges for policy makers. J Chiropr Humanit. 2013;20(1):9-18. doi: 10.1016/j.echu.2013.07.001.

13. Martin BI, Gerkovich MM, Deyo RA, et al. The association of complementary and alternative medicine use and health care expenditures for back and neck problems. Med Care. 2012;50(12):1029-1036. doi: 10.1097/MLR.0b013e318269e0b2.

14. Stano M, Smith M. Chiropractic and medical costs of low back care. Med Care. 1996;34(3):191-204.

15. Luo W, Wang F. Measures of spatial accessibility to health care in a GIS environment: synthesis and a case study in the Chicago region. Environ Plann B Plann Des. 2003;30(6):865-884. doi: 10.1068/b29120.

16. McGrail MR. Spatial accessibility of primary health care utilising the two step floating catchment area method: an assessment of recent improvements. Int J Health Geogr. 2012;11:50. doi: 10.1186/1476-072X-11-50.

17. Cherkin DC, Deyo RA, Volinn E, Loeser JD. Use of the International Classification of Diseases (ICD-9-CM) to identify hospitalizations for mechanical low back problems in administrative databases. Spine (Phila Pa 1976). 1992;17(7):817-825.

18. Crosswalk: Medicare provider/supplier to healthcare provider taxonomy. CMS website. Published November 30, 2017. Accessed November 15, 2018.

19. Consumer Price Index. Bureau of Labor Statistics website. Accessed July 9, 2019.

20. Deyo RA, Cherkin DC, Ciol MA. Adapting a clinical comorbidity index for use with ICD-9-CM administrative databases. J Clin Epidemiol. 1992;45(6):613-619. doi: 10.1016/0895-4356(92)90133-8.

21. Davis MA, Mackenzie TA, Coulter ID, Whedon JM, Weeks WB. The United States chiropractic workforce: an alternative or complement to primary care? Chiropr Man Therap. 2012;20(1):35. doi: 10.1186/2045-709X-20-35.

22. Cheng SH, Lee TT, Chen CC. A longitudinal examination of a pay-for-performance program for diabetes care: evidence from a natural experiment. Med Care. 2012;50(2):109-116. doi: 10.1097/MLR.0b013e31822d5d36.

23. Costello EJ, Compton SN, Keeler G, Angold A. Relationships between poverty and psychopathology: a natural experiment. JAMA. 2003;290(15):2023-2029. doi: 10.1001/jama.290.15.2023.

24. Song Y, Skinner J, Bynum J, Sutherland J, Wennberg JE, Fisher ES. Regional variations in diagnostic practices [erratum in N Engl J Med. 2010;363(2):198. doi: 10.1056/NEJMx100034]. N Engl J Med. 2010;363(1):45-53. doi: 10.1056/NEJMsa0910881.

25. Finkelstein A, Gentzkow M, Williams H. Sources of geographic variation in health care: evidence from patient migration. Q J Econ. 2016;131(4):1681-1726. doi: 10.1093/qje/qjw023.

26. Hill AB. The environment and disease: association or causation? Proc R Soc Med. 1965;58:295-300.

27. Davis MA, Anthopolos R, Tootoo J, Titler M, Bynum JPW, Shipman SA. Supply of healthcare providers in relation to county socioeconomic and health status. J Gen Intern Med. 2018;33(4):412-414. doi: 10.1007/s11606-017-4287-4.

28. Deyo RA, Jarvik JG, Chou R. Low back pain in primary care. BMJ. 2014;349:g4266. doi: 10.1136/bmj.g4266.

29. Srinivas SV, Deyo RA, Berger ZD. Application of “less is more” to low back pain. Arch Intern Med. 2012;172(13):1016-1020. doi: 10.1001/archinternmed.2012.1838.

30. Mafi JN, McCarthy EP, Davis RB, Landon BE. Worsening trends in the management and treatment of back pain [erratum in JAMA Intern Med. 2015;175(5):869. doi: 10.1001/jamainternmed.2015.1589]. JAMA Intern Med. 2013;173(17):1573-1581. doi: 10.1001/jamainternmed.2013.8992.

31. Davis MA, Onega T, Weeks WB, Lurie JD. Where the United States spends its spine dollars: expenditures on different ambulatory services for the management of back and neck conditions. Spine (Phila Pa 1976). 2012;37(19):1693-1701. doi: 10.1097/BRS.0b013e3182541f45.

32. Vogt MT, Kwoh CK, Cope DK, Osial TA, Culyba M, Starz TW. Analgesic usage for low back pain: impact on health care costs and service use. Spine (Phila Pa 1976). 2005;30(9):1075-1081. doi: 10.1097/01.brs.0000160843.77091.07.

33. Weinstein JN, Lurie JD, Olson PR, Bronner KK, Fisher ES. United States’ trends and regional variations in lumbar spine surgery: 1992-2003. Spine (Phila Pa 1976). 2006;31(23):2707-2714. doi: 10.1097/01.brs.0000248132.15231.fe.

34. Lurie JD, Birkmeyer NJ, Weinstein JN. Rates of advanced spinal imaging and spine surgery. Spine (Phila Pa 1976). 2003;28(6):616-620. doi: 10.1097/01.BRS.0000049927.37696.DC.

35. Webster BS, Cifuentes M, Verma S, Pransky G. Geographic variation in opioid prescribing for acute, work-related, low back pain and associated factors: a multilevel analysis. Am J Ind Med. 2009;52(2):162-171. doi: 10.1002/ajim.20655.

36. Chiropractic services in the Medicare program: payment vulnerability analysis. HHS Office of Inspector General website. Published March 2005. Accessed November 15, 2018.

37. Inappropriate Medicare payments for chiropractic services. HHS Office of Inspector General website. Published May 2009. Accessed November 15, 2018.

38. Hundreds of millions in Medicare payments for chiropractic services did not comply with Medicare requirements. HHS Office of Inspector General website. Published 2016. Accessed November 15, 2018.

39. Davis MA, Yakusheva O, Gottlieb DJ, Bynum JP. Regional supply of chiropractic care and visits to primary care physicians for back and neck pain. J Am Board Fam Med. 2015;28(4):481-490. doi: 10.3122/jabfm.2015.04.150005.
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