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Research Review By Dr. Michael Haneline©


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Date Posted:

January 2023

Study Title:

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


Emary P, Brown A, Oremus M, et al.

Author's Affiliations:

Department of Health Research Methods, Evidence and Impact, McMaster University, Canada; Chiropractic Department, D’Youville University, Buffalo, New York, USA; Private practice, Cambridge, Ontario, Canada; School of Public Health Sciences, University of Waterloo, Ontario, Canada

Publication Information:

Journal of Manipulative & Physiological Therapeutics 2022; (45)4: 235-47.

Background Information:

Although commonly prescribed in North America for musculoskeletal (MSK) pain, opioids have been shown to only offer limited benefits (1) and are often associated with serious harms, including death (2, 3) – 60,000 deaths (!) in the United States in 2016 alone (4). In recent years, with the added strain of the COVID-19 pandemic, this number is reaching or exceeding 100 000 per year now!

Patients who are prescribed opioids for back pain or another type of MSK condition, often young adult men mainly, make up a significant proportion of the ongoing opioid crisis. A pilot project, which lacked a control group, evaluated an integrated chiropractic spine pain program, and found that 82% of patients who received chiropractic care reported a significant reduction in the use of analgesics (5). Similar uncontrolled studies conducted in the USA have reported associations between receiving chiropractic care and reduced use of opioids. Nevertheless, comparative assessments of the integration of chiropractic services into primary care settings and opioid use are sparse.

The objective of this study was to perform 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.

The hypotheses were that chiropractic care would be inversely associated with receipt of opioids and that younger age, male sex, having comorbid depression, anxiety, fibromyalgia, diabetes or cardiovascular disease, obesity, positive smoking status, a higher frequency of health care provider visits, and that earlier years of the authors’ 7-year study timeframe would be positively associated with receipt of opioids.

Pertinent Results:

Retrospective Review of Patient Records:
945 out of 1166 patient records from a Canadian Community Health Center met the study’s inclusion criteria and were included in the quantitative analysis. 227 patients received an initial opioid prescription, with most (75%) of them being prescribed opioids within 12 months after their first visit. 183 out of 945 patients (19%) received chiropractic services, with 48% of them receiving chiropractic services within 30 days of their index visit (i.e. receiving ‘early’ chiropractic care).

Recipients of chiropractic care were more commonly female, depressed, or diabetic compared to nonrecipients. There was an inverse association between receipt versus nonreceipt of chiropractic care and opioid prescribing, with recipients having a hazard ratio (HR) of 0.48 (a 52% lower risk!). At year 1, 51% of patients without chiropractic care received opioids as compared to 29% of patients who received chiropractic care. Patients who received early chiropractic care had an even lower risk of initiating a prescription for opioids (HR: 0.29) – this amounts to a 71% lower risk of being prescribed opioids! At year 1, 49% of patients without early chiropractic care received opioids compared to 18% of early chiropractic care recipients. Patients who entered the study in later years were generally less likely to receive opioids (HR: 0.86).

Variables that were positively associated with receipt of opioids included a higher frequency of health care visits (HR: 1.02), older age (HR: 1.02), smoking (HR: 1.62), and depression (HR: 1.77). Other variables, such as male sex, obesity, anxiety, fibromyalgia, diabetes, and cardiovascular disease were not associated with receipt of opioids. There were also no significant interactions between receipt of chiropractic care and age, smoking, depression, or health care visit frequency.

Participant Interviews:
79% of the patients who were interviewed were women, 86% of them were receiving disability benefits or were unemployed, and 71% were previously prescribed opioids for noncancer spinal pain.

A total of 23 interviews were completed, 14 with patients and 9 with GPs/NPs (medical doctors and nurse practitioners). 12 GPs/NPs were invited for interviews, although 3 of them declined participation, and 23 patients were invited for interviews. 3 GPs/NPs and 1 non-chiropractic patient requested minor revisions to clarify statements made during their interviews.

Codes were identified during interviews and data saturation was considered to be reached when no new codes emerged from two consecutive GP/NP or patient interviews. 37 codes were found during interviews which were categorized into 4 major themes:
  1. patient self-efficacy (subthemes, active vs. passive approaches and resistance to taking medication);
  2. accessibility of nonpharmacological services (subthemes, lack of access to non-pharmacological services and access to chiropractic care at the center);
  3. stigma regarding use of opioids; and
  4. impact of treatment (subthemes of pain relief, functionality, and anxiety and fear surrounding opioid withdrawal).

Clinical Application & Conclusions:

Spinal pain patients in this study were less likely to receive opioids if they received chiropractic care as compared to patients who did not receive chiropractic care, especially among patients who had early access to chiropractic services. The qualitative interviews revealed 4 themes: 1) patient self-efficacy; 2) access to chiropractic services; 3) stigma regarding use of opioids; and 4) impact of treatment. Awareness of these 4 themes enables a richer understanding of the quantitative findings.

The findings of this study are in agreement with what other researchers have reported, which shows consistently that chiropractic care is associated with a reduced risk of opioid prescribing (6, 7). This gives credence to adding chiropractic services to primary care centers which could reduce the need for opioid prescribing and have a positive impact on the opioid crisis. This paper certainly adds to our growing body of evidence in this space!

Commentary from lead author, Dr. Peter Emary:
I conducted this study under the supervision of Professor Jason W. Busse, DC, PhD as part of my PhD thesis at McMaster University. For this project, we looked at the association between receiving chiropractic care and initiating a prescription for opioids among patients with non-cancer spinal pain attending the Langs Community Health Centre (CHC) in Cambridge, Ontario, Canada. One of the most important implications of our findings is that earlier access to chiropractic care may provide a greater protective effect in reducing the number of people obtaining opioid prescriptions. I also really enjoyed sitting down and speaking with the patients and medical providers from the CHC in our interviews. The information we collected from participants was extremely valuable as it gave us a better understanding of why chiropractic care might be helpful in reducing patients’ reliance on opioid medication. Overall, our findings highlight the need for better access to non-pharmacological services, including chiropractic care, particularly among vulnerable or marginalized patient populations. However, observational research has its limitations. Therefore, for the next stage of our research, we plan to conduct a randomized clinical trial to further explore our findings.

About Dr. Emary: Dr. Emary has been in clinical practice for over 19 years and currently practices part-time at the Langs CHC. He’s also a postdoctoral fellow at the Michael G. DeGroote National Pain Centre at McMaster University and teaches in the Chiropractic Department at D’Youville University (NY, USA).

Study Methods:

A sequential, explanatory, mixed methods design was utilized in this study, in which follow-up qualitative data were collected to clarify and explain the quantitative findings that were collected in the first phase of the study. The mixed methods design included an interview component to better understand whether chiropractic services were used by patients and general medical physicians/nurse practitioners (GPs/NPs) to reduce reliance on opioids.

A retrospective chart review of electronic medical records (EMRs) was conducted for all adult patients (aged ≥18 years) with 2 or more visits for a diagnosis of back or neck pain (non-cancer) between January 1, 2014, and December 31, 2020. Patients were excluded from analysis if they had contraindications to chiropractic treatment (i.e. fractures, infections, inflammatory arthritis, or cauda equina syndrome).

Exposure was considered the addition of chiropractic care (at least 1 visit during the 7-year study period) to ongoing GP/NP care as compared with ongoing GP/NP care alone. As compared to a recipient of chiropractic care, a nonrecipient was defined as someone who received 2 or more GP/NP visits alone.

The main outcome variable was the amount of time to first opioid prescription. All data were extracted by a blinded information technology specialist directly from the EMRs. Twelve variables were chosen which, based on previous literature, the authors thought might be associated with time to first opioid prescription, including chiropractic care, calendar year, frequency of health care visits, age, sex, smoking status, obesity, depression, anxiety, fibromyalgia, diabetes, and cardiovascular disease. Any of these variables with fewer than 50 total observations were excluded from the analysis.

Interviews were also conducted on a minimum of 6 GPs/NPs and 12 patients, which were continued until no new information was obtained from the participants. Interviews were semi-structured and carried out individually (one-on-one) by the lead author. Interview guides were developed by the team of researchers based on their quantitative findings and relevant literature.

Study Strengths / Weaknesses:

This was a well-conducted observational study that included sophisticated statistical analyses which bolster its conclusions. There are, however, some inherent weaknesses associated with this type of study that may limit its generalizability. On the other hand, the fact that numerous other studies on this topic have reached similar conclusions strengthen generalizability.

The authors listed several other study limitations, including:
  • a retrospective design was used;
  • some pertinent variables were unavailable (ex. baseline spine-related pain severity/chronicity and social determinants of health);
  • the primary outcome, time to first opioid prescription, is not a patient-centered outcome, like pain reduction or functional improvement;
  • chiropractic care recipients may have been prognostically different from nonrecipients, even though adjustments for confounding were made;
  • the use of a sequential mixed methods design that involved quantitative followed by qualitative phases that were separated by 11 months resulted in some individuals no longer being available for interviews; and
  • opioids may have been prescribed for other indications, which would weaken the association between chiropractic care and opioid receipt.
Due to limitations of the observational research design that was used, the authors suggested that well-designed randomized controlled trials be conducted on this topic.

Additional References:

  1. Busse J, Wang L, Kamaleldin M, et al. Opioids for chronic noncancer pain: a systematic review and meta-analysis. JAMA 2018; 320(23): 2448-2460.
  2. Busse J, Craigie S, Juurlink D, et al. Guideline for opioid therapy and chronic noncancer pain. CMAJ 2017; 189(18): E659-66.
  3. Bedson J, Chen Y, Ashworth J, Hayward R, Dunn K, Jordan K. Risk of adverse events in patients prescribed longterm opioids: a cohort study in the UK Clinical Practice Research Datalink. Eur J Pain 2019; 23(5): 908-22.
  4. Rummans T, Burton M, Dawson N. How good intentions contributed to bad outcomes: the opioid crisis. Mayo Clin Proc 2018; 93(3): 344-350.
  5. Emary P, Brown A, Cameron D, et al. 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 2017; 40(9): 635-42.
  6. Whedon J, Toler A, Kazal L, Bezdjian S, Goehl J, Greenstein J. Impact of chiropractic care on use of prescription opioids in patients with spinal pain. Pain Med 2020; 21(12): 3567-73.
  7. Whedon J, Uptmor S, Toler A, Bezdjian S, MacKenzie T, Kazal L. Association between chiropractic care and use of prescription opioids among older Medicare beneficiaries with spinal pain: a retrospective observational study. Chiropr Man Therap 2022; 30(1): 5.

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