Association of Chiropractic Care With Receiving an Opioid
Prescription for Noncancer Spinal Pain Within a Canadian
Community Health Center: A Mixed Methods Analysis

This section is compiled by Frank M. Painter, D.C.
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FROM:   J Manipulative Physiol Ther 2022 (Aug 23); S0161-4754(22)00086-0 ~ FULL TEXT


Peter C. Emary DC, MS, Amy L. Brown DC, Mark Oremus MSc, PhD,
Lawrence Mbuagbaw MD, MPH, PhD, Douglas F. Cameron DC,
Jenna DiDonato HBSc(Kin), Jason W. Busse DC, MS, PhD

Department of Health Research Methods, Evidence and Impact,
McMaster University,
Waterloo, Ontario, Canada.

FROM:   Kazis et. al, BMJ Open 2019

Objective:   The purpose of this study was to examine the association between receipt of chiropractic services and initiating a prescription for opioids among adult patients with noncancer spinal pain in a Canadian community health center.

Methods:   In this sequential explanatory mixed methods analysis, we conducted a retrospective study of 945 patient records (January 2014 to December 2020) and completed interviews with 14 patients and 9 general practitioners. We used Cox proportional hazards regression analyses, adjusted for patient demographics, comorbidities, visit frequency, and calendar year to evaluate the association between receipt of chiropractic care and time to first opioid prescription up to 1 year after presentation. Qualitative data were analyzed thematically and integrated with our quantitative findings.

Results:   There were 24% of patients (227 of 945) with noncancer spinal pain who received a prescription for opioids. The risk of initiating a prescription for opioids at 1 year after presentation was 52% lower in chiropractic recipients vs nonrecipients (hazard ratio [HR], 0.48; 99% confidence interval [CI], 0.29–0.77) and 71% lower in patients who received chiropractic services within 30 days of their index visit (HR, 0.29; 99% CI, 0.13–0.68). Patients whose index visit date was in a more recent calendar year were also less likely to receive opioids (HR, 0.86; 99% CI, 0.76–0.97). Interviews suggested that self-efficacy, access to chiropractic services, opioid stigma, and treatment impact were influencing factors.

Conclusion:   Patients with noncancer spinal pain who received chiropractic care were less likely to obtain a prescription for opioids than patients who did not receive chiropractic care.

Keywords:   Analgesics, Opioid; Chiropractic; Community Health Centers; Health Services Research.

From the FULL TEXT Article:


Opioid medications are commonly prescribed in North America to relieve musculoskeletal (MSK) pain and improve function. [1] However, opioids provide only modest benefits [2] and are associated with important harms, including addiction, overdose, and death. [3–6] There were 2,4626 opioid-related deaths and 2,7604 opioid-related hospitalizations in Canada between January 2016 and June 2021. [7] In the United States (US), there were approximately 60000 opioid-related deaths in 2016 alone. [8] Young adult men have been most affected by the opioid crisis, [7, 8] which has arisen partly among individuals who were initially prescribed opioids for back pain or some other MSK condition. [8–11] Recent reports from Canada and the US indicate that opioid-related deaths have increased during the COVID-19 pandemic. [7, 12] Some chiropractors have called on governments, policymakers, and insurers to improve support for nonopioid approaches for managing MSK-related pain, including noncancer back and neck pain, particularly in vulnerable or marginalized populations. [11]

In 2017, we conducted a pilot project evaluating a newly integrated chiropractic spine pain program at Langs Community Health Center (CHC) in Ontario, Canada, [13–15] and found that 82% of patients who received chiropractic care reported a significant reduction in the use of analgesics. [13, 16] However, similar to research on chiropractic integration within other Canadian primary care centers, [17–22] our study was limited by the absence of a comparison group. [13, 16] Moreover, although several uncontrolled studies reported an association between reduced use of opioids and receipt of chiropractic care in various US populations, [23–26] comparative assessments of the integration of chiropractic services into primary care settings are sparse. [27, 28] In addition, the impact and understanding of such integration on prescription opioid use in noncancer MSK pain management remain uncertain.

To address these knowledge gaps, we undertook a mixed methods analysis to examine the association between receipt of chiropractic services and opioid prescriptions among adult patients with noncancer spinal pain in a primary care setting. We hypothesized that chiropractic care would be inversely associated with receipt of opioids. Further, we hypothesized that younger age, male sex, presenting with comorbid depression, anxiety, fibromyalgia, diabetes or cardiovascular disease, obesity, positive smoking status, a higher frequency of health care provider visits, and earlier years of our 7–year study timeframe would be positively associated with opioid receipt. [29]


This study was one of the first to examine the relationship between chiropractic integration and opioid use among vulnerable patients with noncancer spinal pain in a CHC setting [22, 28] and the first to do so using a mixed methods approach. In our quantitative analysis, we found that receipt of chiropractic care was associated with a decreased likelihood of receiving an opioid prescription, and our follow-up interviews identified several potential influencing factors in this relationship. Our quantitative results are consistent with those of other uncontrolled observational studies. [23–26, 54] For instance, a systematic review and meta-analysis of 6 cohort studies [23] found that patients with noncancer back or neck pain who received chiropractic services were nearly two-thirds less likely than nonchiropractic users to be prescribed opioids (pooled odds ratio, 0.36; 95% CI, 0.30–0.43). In 2 more recent studies, [25, 26] the risk of filling an opioid prescription among US adults [25] and older Medicare beneficiaries [26] with noncancer spinal pain was reduced by half for recipients of chiropractic services. In keeping with our findings, this reduction was greater among patients who saw a chiropractor within the first 30 days of treatment. [25, 26] An association between reduced opioid use for spinal pain with early access to nonpharmacological services (eg, chiropractic, physical therapy) has also been reported by others. [22, 24, 54, 55]

We gained several insights into our quantitative findings by integrating quantitative and qualitative methods. Based on our interviews, we perceive that patients who were referred for chiropractic services at Langs CHC may have been more resistant to taking medication in general and opioids in particular than patients who were not referred for chiropractic services. GPs/NPs indicated that access to chiropractic treatment gave them another nonopioid pain management option. In addition, a negative stigma regarding use of prescription opioids was identified by several chiropractic patients and GPs/NPs as a barrier to opioid use. These factors may help explain why chiropractic recipients were less likely to be prescribed opioids. We also found that when accessed as a first-line treatment, chiropractic care may have helped to delay, and in some cases prevent, opioid prescription. Our data suggest that by 1 year, access to chiropractic care resulted in an additional 22% of patients not receiving a prescription for opioids. When chiropractic care was accessed within 30 days of visiting the CHC, an additional 31% of patients avoided an opioid prescription. Thus, it appears that earlier access to chiropractic care may have had a greater protective effect in reducing the number of people obtaining opioid prescriptions.

Similar to previous research, [4, 44–46] we found that positive smoking status and comorbid depression were strongly associated with opioid use in our sample (ie, increased risk of 62% and 77%, respectively). In the 2017 Canadian opioid guideline, [4] we found that comorbid mental illness was associated with an increased risk of opioid use disorder, as well as nonfatal and fatal opioid overdose when chronic pain patients were prescribed opioids. As such, a weak/conditional recommendation was made to avoid prescribing opioids to patients with active psychiatric disorders until their comorbid mental illness has been stabilized. [4] Our current findings suggest that patients with comorbid depression were more likely to receive prescription opioids, which is cause for concern.

Our findings and those of other researchers suggest that chiropractic services are consistently associated with a reduced risk of opioid prescribing, as well as improved patient outcomes and potential for cost savings (eg, reductions in GP/NP visits, advanced imaging, and specialist referrals). [13, 16–26, 28] As such, with further integration of chiropractic services into primary care centers, [13, 16–26, 28] the potential benefits for the opioid crisis, including how these patients are managed in CHCs and other health care settings, could be substantial.


First, we included a robust set of potential confounders in our multivariable regression models to minimize the possibility of residual confounding. Second, we prespecified the anticipated direction of association for each independent variable in our regression models and set our significance level to 1% to provide greater confidence in our findings. Third, we controlled for the calendar year in our analyses to account for policy changes in opioid prescribing. Additional strengths included direct data export from the EMR to avoid extraction errors,34 limited missing data (<1%), and validation of our qualitative data via member-checking. The qualitative component of our study also provided a richer understanding of our quantitative findings.

      Limitations and Future Studies

In the quantitative phase of our study, a limitation was the retrospective design, and certain variables that may be important to consider were unavailable. For example, due to the constraints of data recorded in Langs EMR, we were unable to extract information on baseline spine-related pain (ie, severity/chronicity) or other cointerventions that patients may have received outside of the CHC. Moreover, we were unable to include race/ethnicity or other social determinants of health as possible covariates in our analysis, [56] as these factors were not captured in the administrative database that we used. However, our findings regarding the association between receipt of chiropractic services and reduced opioid prescriptions were consistent with other studies that controlled for the duration of low back or neck pain. [24, 54, 55] Moreover, due to socioeconomic disadvantages, [13–19, 21, 22] most Langs CHC patients would be unlikely to have accessed private health care services elsewhere.

A second limitation is that our primary outcome, time to first opioid prescription, is a surrogate for patient-centered outcomes, such as pain reduction or functional improvement.

Third, as highlighted by our interviews, recipients of chiropractic care may have been prognostically different from nonrecipients despite our adjustments for confounding. Notwithstanding, recipients had a higher prevalence of depression, which, based on our data, should have increased their risk of opioid use (see crude association under the “Univariate” column in Table 2). However, when we controlled for depression in our adjusted analyses, recipients had a lower risk of opioid receipt.

Fourth, a limitation in using a sequential mixed methods design (ie, quantitative followed by qualitative) was that 11 months elapsed between our quantitative and qualitative data collection. As such, some individuals whom we attempted to recruit from the larger cohort were no longer available for interviews (eg, moved out of city, phone number no longer in service, or were deceased).

Fifth, a limitation of the qualitative phase of our study is that we did not pilot-test our interview guides. However, 1–week in advance of participant interviews, patients and GPs/NPs received an information form containing examples of their interview questions.

Sixth, and in line with our published protocol, [29] we interviewed patients and GPs/NPs to gain their perspectives on chiropractic integration at Langs CHC and its impact on opioid prescribing. However, the input of other stakeholders, such as administrators, chiropractors, or other allied health professionals (eg, nurses, dieticians, or physical therapists), might have revealed additional themes and subthemes to inform our research question.

Seventh, as reported in Supplementary File 4 (see “Relationship with Participants”), a previous therapeutic relationship had been established between the lead author (P.C.E.) and 2 of the 8 chiropractic patients who were interviewed for this study. This may have influenced the results in these 2 interviews; however, in neither case was care being provided at the time of the interview.

A final limitation of our mixed methods study is the findings may be generalizable to some, but not all, clinic programs outside of Langs CHC.

Although our results and those of previous studies on the association between chiropractic care and prescription opioid use are promising, [22–26, 54] observational research is prone to selection bias. As such, well-designed randomized controlled trials (eg, Goertz et al [27]) are urgently needed to confirm or refute these findings. A multistage, mixed methods, randomized controlled trial is needed to further explore our findings.


Our analysis found that patients with spine pain who received chiropractic care were less likely to receive opioids compared to patients who did not receive chiropractic care. This relationship was most pronounced among patients with early access to chiropractic services. Four themes emerged in our qualitative interviews, including patient self-efficacy, access to chiropractic services, stigma regarding use of opioids, and impact of treatment, which provide a richer understanding of this association.

Practical Applications
  • Our analysis found that receipt of chiropractic care was associated with a large decrease in opioid prescribing.

  • When accessed as a first-line treatment, chiropractic care may have helped to delay and, in some cases, prevent opioid prescription.

  • Our qualitative findings suggested that patient self-efficacy, access to chiropractic services, opioid stigma, and treatment impact were important influencing factors.

  • Our findings, combined with those of other researchers, suggest that further integration of chiropractic services into primary care centers could positively affect the opioid crisis.


  1. International Narcotics Control Board.
    Narcotic drugs 2019: estimated world requirements for 2020. Available at:
    Accessed January 31, 2022.

  2. JW Busse, L Wang, M Kamaleldin, et al.
    Opioids for chronic noncancer pain: a systematic review and meta-analysis
    JAMA, 320 (23) (2018), pp. 2448-2460

  3. Gomes T, Greaves S, Martins D, et al.
    Latest trends in opioid-related deaths in Ontario: 1991 to 2015. Available at:
    Accessed January 31, 2022.

  4. Busse, JW, Craigie, S, Juurlink, DN et al.
    Guideline for Opioid Therapy and Chronic Noncancer Pain
    CMAJ. 2017 (May 8); 189 (18): E659–E666

  5. J Bedson, Y Chen, J Ashworth, RA Hayward, KM Dunn, KP. Jordan
    Risk of adverse events in patients prescribed long-term opioids:
    a cohort study in the UK Clinical Practice Research Datalink
    Eur J Pain, 23 (5) (2019), pp. 908-922

  6. JA Gwira Baumblatt, C Wiedeman, JR Dunn, W Schaffner, LJ Paulozzi, TF Jones
    High-risk use by patients prescribed opioids for pain and its role in overdose deaths
    JAMA Intern Med, 174 (5) (2014), pp. 796-801

  7. Public Health Agency of Canada.
    Apparent opioid and stimulant toxicity deaths:
    surveillance of opioid- and stimulant-related harms in Canada
    (January 2016 to June 2021). Available at:
    Accessed January 31, 2022.

  8. TA Rummans, MC Burton, NL. Dawson
    How good intentions contributed to bad outcomes: the opioid crisis
    Mayo Clin Proc, 93 (3) (2018), pp. 344-350

  9. L Manchikanti, S Helm 2nd, B Fellows, et al.
    Opioid epidemic in the United States
    Pain Physician, 15 (3 Suppl) (2012), pp. ES9-ES38

  10. L Belzak, J. Halverson
    The opioid crisis in Canada: a national perspective
    Health Promot Chronic Dis Prev Can, 38 (6) (2018), pp. 224-233

  11. Canadian Chiropractic Association.
    A better approach to pain management: responding to Canada's opioid crisis. Available at:
    Accessed January 31, 2022.

  12. L Manchikanti, R Vanaparthy, S Atluri, H Sachdeva, AD Kaye, JA. Hirsch
    COVID-19 and the opioid epidemic:
    two public health emergencies that intersect with chronic pain
    Pain Ther, 10 (1) (2021), pp. 269-286

  13. PC Emary, AL Brown, DF Cameron, AF Pessoa, JE. Bolton
    Management of back pain-related disorders in a community with limited access
    to health care services: a description of integration of chiropractors as service providers
    J Manipulative Physiol Ther, 40 (9) (2017), pp. 635-642

  14. Langs.
    Cambridge: Langs Community Health Centre. Available at:
    Accessed January 31, 2022.

  15. Community Health Centres.
    Toronto: Ontario Ministry of Health and Long-Term Care; 2021. Available at:
    Accessed January 31, 2022.

  16. PC Emary, AL Brown, DF Cameron, AF. Pessoa
    Chiropractic Integration Within a Community Health Centre:
    A Cost Description and Partial Analysis of Cost-utility
    from the Perspective of the Institution

    J Can Chiropr Assoc. 2019 (Aug); 63 (2): 64–79

  17. MJ Garner, P Aker, J Balon, M Birmingham, D Moher, D Keenan, P. Manga
    Chiropractic Care of Musculoskeletal Disorders in a Unique
    Population Within Canadian Community Health Centers

    J Manipulative Physiol Ther 2007 (Mar); 30 (3): 165–170

  18. S Mior, B Gamble, J Barnsley, P Côté, E. Côté
    Changes in Primary Care Physician's Management of Low Back Pain
    in a Model of Interprofessional Collaborative Care:
    An Uncontrolled Before-After Study

    Chiropractic & Manual Therapies 2013 (Feb 1); 21 (1): 6

  19. Passmore SR, Toth A, Kanavosky J, Olin G.
    Initial Integration of Chiropractic Services into a Provincially Funded
    Inner City Community Health Centre: A Program Description

    J Can Chiropr Assoc 2015 (Dec); 59 (4): 363–372

  20. Centre for Effective Practice.
    Primary care low back pain pilot evaluation: final report.
    Toronto: Centre for Effective Practice; 2017.

  21. C Manansala, S Passmore, K Pohlman, A Toth, G. Olin
    Change in Young People's Spine Pain Following Chiropractic Care
    at a Publicly Funded Healthcare Facility in Canada

    Complement Ther Clin Pract. 2019 (May); 35: 301–307

  22. S Passmore, C Manansala, Q Malone, EA Toth, GM Olin
    Opioid usage patterns, patient characteristics, and the role of
    chiropractic services in a publicly funded inner city health care facility
    Spine J, 19 (2019), pp. S78-S79

  23. Corcoran KL, Bastian LA, Gunderson CG, et al.
    Association Between Chiropractic Use and Opioid Receipt Among
    Patients with Spinal Pain: A Systematic Review and Meta-analysis

    Pain Medicine 2020 (Feb 1); 21 (2): e139–e145

  24. Kazis LE, Ameli O, Rothendler J, et al.
    Observational Retrospective Study of the Association of Initial
    Healthcare Provider for New-onset Low Back Pain with
    Early and Long-term Opioid Use

    BMJ Open. 2019 (Sep 20); 9 (9): e028633

  25. Whedon JM, Toler AWJ, Kazal LA, Bezdjian S, Goehl JM, Greenstein J.
    Impact of Chiropractic Care on Use of Prescription Opioids
    in Patients with Spinal Pain

    Pain Medicine 2020 (Dec 25); 21 (12): 3567–3573

  26. JM Whedon, S Uptmor, AWJ Toler, S Bezdjian, TA MacKenzie, LA Jr. Kazal
    Association Between Chiropractic Care and Use of Prescription
    Opioids Among Older Medicare Beneficiaries with Spinal Pain:
    A Retrospective Observational Study

    Chiropractic & Manual Therapies 2022 (Jan 31); 30: 5

  27. Goertz CM, Long CR, Vining RD, Pohlman KA, Walter J, Coulter I.
    Effect of Usual Medical Care Plus Chiropractic Care vs Usual Medical Care
    Alone on Pain and Disability Among US Service Members With
    Low Back Pain. A Comparative Effectiveness Clinical Trial

    JAMA Network Open. 2018 (May 18); 1 (1): e180105   NCT01692275

  28. C Prater, M Tepe, P. Battaglia
    Integrating a Multidisciplinary Pain Team and Chiropractic
    Care in a Community Health Center: An Observational
    Study of Managing Chronic Spinal Pain

    J Primary Care & Community Health 2020 (Sep 10)

  29. PC Emary, M Oremus, L Mbuagbaw, JW. Busse
    Association of chiropractic integration in an Ontario community health centre
    with prescription opioid use for chronic non-cancer pain: a mixed methods study protocol
    BMJ Open, 11 (11) (2021), Article e051000

  30. A O'Cathain, E Murphy, J. Nicholl
    The quality of mixed methods studies in health services research
    J Health Serv Res Policy, 13 (2) (2008), pp. 92-98

  31. S Fàbregues, QN Hong, EL Escalante-Barrios, TC Guetterman, J Meneses, MD. Fetters
    A methodological review of mixed methods research in
    palliative and end-of-life care (2014-2019)
    Int J Environ Res Public Health, 17 (11) (2020), p. 3853

  32. JW Creswell, VL Plano Clark
    Designing and Conducting Mixed Methods Research (3rd ed.),
    SAGE Publishing, Thousand Oaks, CA (2018)

  33. JC Greene, VJ Caracelli, WF. Graham
    Toward a conceptual framework for mixed-method evaluation designs
    Educ Eval Policy Anal, 11 (3) (1989), pp. 255-274

  34. M Vassar, M. Holzmann
    The retrospective chart review: important methodological considerations
    J Educ Eval Health Prof, 10 (2013), p. 12

  35. K Yadav, RJ. Lewis
    Immortal time bias in observational studies
    JAMA, 325 (7) (2021), pp. 686-687

  36. BC Choi, AL. Noseworthy
    Classification, direction, and prevention of bias in epidemiologic research
    J Occup Med, 34 (3) (1992), pp. 265-271

  37. PS Nolet, P Côté, JD Cassidy, LJ. Carroll
    The association between self-reported cardiovascular disorders
    and troublesome neck pain: a population-based cohort study
    J Manipulative Physiol Ther, 35 (3) (2012), pp. 176-183

  38. DP Ritzwoller, L Crounse, S Shetterly, D. Rublee
    The association of comorbidities, utilization and costs
    for patients identified with low back pain
    BMC Musculoskelet Disord, 7 (2006), p. 72

  39. B Bath, C Trask, J McCrosky, J. Lawson
    A biopsychosocial profile of adult Canadians with and without
    chronic back disorders: a population-based analysis of
    the 2009-2010 Canadian Community Health Surveys
    Biomed Res Int, 2014 (2014), Article 919621

  40. Gore M, Sadosky A, Stacey BR, Tai KS, Leslie D.
    The Burden of Chronic Low Back Pain: Clinical Comorbidities,
    Treatment Patterns, and Health Care Costs in Usual Care Settings

    Spine (Phila Pa 1976). 2012 (May 15); 37 (11): E668–677

  41. D Robertson, D Kumbhare, P Nolet, J Srbely, G. Newton
    Associations between low back pain and depression and
    somatization in a Canadian emerging adult population
    J Can Chiropr Assoc, 61 (2) (2017), pp. 96-105

  42. D Feingold, S Brill, I Goor-Aryeh, Y Delayahu, S. Lev-Ran
    The association between severity of depression and prescription opioid misuse
    among chronic pain patients with and without anxiety: a cross- sectional study
    J Affect Disord, 235 (2018), pp. 293-302

  43. B Han, WM Compton, C Blanco, E Crane, J Lee, CM. Jones
    Prescription opioid use, misuse, and use disorders in U.S. adults:
    2015 National Survey on Drug Use and Health
    Ann Intern Med, 167 (5) (2017), pp. 293-301

  44. Lisi AJ, Corcoran KL, DeRycke EC, et al.
    Opioid Use Among Veterans of Recent Wars Receiving
    Veterans Affairs Chiropractic Care

    Pain Medicine 2018 (Sep 1); 19 (suppl_1): S54–S60

  45. Carroll LJ, Hogg-Johnson S, van der Velde G, Haldeman S, Holm LW, et al.
    Course and Prognostic Factors for Neck Pain in the General Population:
    Results of the Bone and Joint Decade 2000–2010 Task Force
    on Pain and Its Associated Disorders

    Spine (Phila Pa 1976). 2008 (Feb 15); 33 (4 Suppl): S75–82

  46. MH. Katz
    Multivariable analysis: a primer for readers of medical research
    Ann Intern Med, 138 (8) (2003), pp. 644-650

  47. JW Busse, S Ebrahim, D Heels-Ansdell, L Wang, R Couban, SD. Walter
    Association of Worker Characteristics and Early Reimbursement
    for Physical Therapy, Chiropractic and Opioid Prescriptions
    With Workers' Compensation Claim Duration, For Cases of
    Acute Low Back Pain: An Observational Cohort Study

    BMJ Open. 2015 (Aug 26); 5 (8): e007836

  48. DG Kleinbaum, LL Kupper, A Nizam, ES. Rosenberg
    Applied Regression Analysis and Other Multivariable Methods
    (5th ed.), Cengage Learning, Boston, MA (2014)

  49. KMT Collins, AJ Onwuegbuzie, QG. Jiao
    A mixed methods investigation of mixed methods sampling designs
    in social and health science research
    J Mix Methods Res, 1 (3) (2007), pp. 267-294

  50. MD Fetters, LA Curry, JW. Creswell
    Achieving integration in mixed methods designs – principles and practices
    Health Serv Res, 48 (6 Pt 2) (2013), pp. 2134-2156

  51. A Tashakkori, C. Teddlien
    Handbook of Mixed Methods in Social and Behavioural Research
    SAGE Publishing, Thousand Oaks, CA (2003)

  52. C Bradshaw, S Atkinson, O. Doody
    Employing a qualitative description approach in health care research
    Glob Qual Nurs Res, 4 (2017), Article 2333393617742282

  53. M. Sandelowski
    Whatever happened to qualitative description?
    Res Nurs Health, 23 (4) (2000), pp. 334-340

  54. Kazis LE, Ameli O, Rothendler J, et al.
    Observational Retrospective Study of the Association of Initial
    Healthcare Provider for New-onset Low Back Pain with
    Early and Long-term Opioid Use

    BMJ Open. 2019 (Sep 20); 9 (9): e028633

  55. Horn ME, George SZ, Fritz JM.
    Influence of Initial Provider on Health Care Utilization
    in Patients Seeking Care for Neck Pain

    Mayo Clin Proc Innov Qual Outcomes. 2017 (Oct 19); 1 (3): 226–233

  56. AS Moriya, L. Xu
    The complex relationships among race/ethnicity, social determinants, and opioid utilization
    Health Serv Res, 56 (2) (2021), pp. 310-322



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