Research Review By Dr. Michael Haneline©

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Date Posted:

June 2021

Study Title:

Impact of Chiropractic Care on Use of Prescription Opioids in Patients with Spinal Pain

Authors:

Whedon J, Toler A, Kazal L, Bezdjian S, Goehl J, Greenstein J

Author's Affiliations:

Southern California University of Health Sciences, Whittier, CA, USA.

Publication Information:

Pain Medicine 2020; 21(12): 3567-73.

Background Information:

There are well-known risks associated with the use of prescription opioids, with nearly 48,000 deaths being attributable to opioid overdose in 2017 in the USA alone (1). Accordingly, there is a pressing need to prevent the unnecessary use of opioids by identifying safe and cost-effective alternative pain treatments.

Nonpharmacological pain treatments, including chiropractic, are receiving increasing attention, especially given that 59% of US adults who were prescribed opioids reported having back pain (2). Furthermore, the Institute of Medicine recommends nonpharmacological therapies as effective alternatives to pharmacotherapy for patients with chronic musculoskeletal pain and the American College of Physicians’ clinical guidelines recommend nonpharmacological treatment as the first-line treatment for back pain (3).

Some early evidence shows that the use of nonpharmacological treatments for musculoskeletal pain has an influence on opioid use. For instance, a recent study reported that among patients treated for spinal pain, expenditures for opioid therapy decreased as expenditures for manual care (chiropractic and physical therapy) increased, as did costs for spinal surgery and spine care overall (4). Another study involving 1,702 neck pain patients reported that those who received chiropractic (DC) care were less likely to be prescribed opioids within one year of their first visit. Several other studies have reported similar findings (5).

The objective of this study was to determine the impact of chiropractic utilization on the use of prescription opioids among patients with spinal pain. This was a follow-up to a previous study the authors performed in New Hampshire. This time, they utilized a larger study population from three New England states, a longer time frame, and more advanced methods.

Pertinent Results:

The total number of subjects was 101,221 that was comprised of a population that was skewed toward younger age groups, likely because Medicare claims were not included.

The time-to-event analysis showed that at any time in the study period, opioid prescriptions were filled between 1.55 and 2.03 times more often among nonrecipients than recipients. Thus, chiropractic recipients were at about half the risk of seeking an opioid over the 6-year follow-up period.

There were significant differences for the acute group in all three states but only in New Hampshire for the nonacute group. The protective effect against risk of prescription fill was higher for the acute group as compared with the nonacute group in Massachusetts and New Hampshire.

The results of the time-to-event analysis revealed a consistent reduction in risk over time for filling a prescription for opioids in all states, although the differences in risk for the acute group as compared with the overall analysis were negligible.

Clinical Application & Conclusions:

In this study, patients with spinal pain disorders who received chiropractic care experienced approximately a 50% reduction in the risk of filling an opioid analgesic prescription over a 6-year period, as compared with patients who did not receive chiropractic care. Furthermore, when patients saw a DC within 30 days of being diagnosed with a spinal pain disorder, the reduction in risk was greater than those who visited a DC after the acute phase had passed.

Given the enormous negative impact that the opioid crisis has had on individuals and society, strategies to minimize the need for opioid prescriptions should be welcomed by all. This study provides further evidence in support of nonpharmacological therapies, chiropractic care in this case, which are important in the prevention of opioid dependance and associated harms.

Study Methods:

This study employed a retrospective cohort design to analyze health insurance claims data to determine whether patients diagnosed with spinal pain were at lower risk of filling a prescription for an opioid analgesic if they received chiropractic services as compared with those who did not receive chiropractic services.

The data were retrieved from the All Payer Claims Databases (APCDs) of the three New England states.

The study population included adults aged 18-84 years who were enrolled in a health plan and visited a primary care physician and/or DC during the study period. Patients also had to have continuous pharmacy coverage and at least two visits associated with a primary diagnosis of a spinal pain disorder between seven and 90 days apart. Patients were excluded if they were diagnosed with cancer or if they had an opioid prescription prior to the index date (the first date associated with a diagnosis of spinal pain).

Two cohorts of subjects were identified:
  1. ”Recipients” of chiropractic services who received both primary care and/or chiropractic care at any point in the study period.
  2. ”Nonrecipients” who received primary care but did not receive chiropractic care at any time during the study period.
Recipients were stratified into the following 2 groups: 1) Acute – patients whose first chiropractic visit occurred within 30 days of the index date; and 2) Nonacute – all other patients.

The likelihood of opioid prescription fill was modeled for up to 6 years of follow-up. Patient demographics and health status at baseline were taken into consideration by calculating from any diagnoses present during the one-year period prior to the index date.

Adjusted time-to-event analyses were performed comparing recipients to nonrecipients regarding the risk of filling an opioid prescription after being diagnosed with a spinal pain disorder. A sub-analysis was performed to assess the effect of receiving chiropractic care early in an episode of care by determining the risk of an opioid prescription in the acute and nonacute groups.

Study Strengths / Weaknesses

In contrast to a previous study on the relationship between chiropractic care and the likelihood of filling an opioid prescription (6), this study included a larger sample that covered 3 contiguous states and followed patients for a much longer period.

The authors listed several main possible sources of bias that might have affected the results of this study, including:
  1. There was potential for misclassification of the time-to-event analysis among recipients through immortal time bias (i.e., when some participants do not experience the outcome during the follow-up period). This bias was eliminated by identifying recipients independently of the timing of their opioid prescription.
  2. There was a potential for confounding by indication, which could occur when patients with more severe pain may have been more likely to use opioid medication.
  3. Chronological bias was also possible in this study, which was apparent in the acute vs nonacute subgroup analysis due to the small number of subjects in the nonacute groups.
  4. Selection bias may have been present if recipients were different from nonrecipients by unmeasured characteristics.
The authors pointed out that despite these potential sources of bias and confounding, the results were remarkably similar across all 3 states.

Additional References:

  1. US Department of Health and Human Services. Facing Addiction in America: The Surgeon General’s Spotlight on Opioids. Washington, DC: Office of the Surgeon General, US Department of Health and Human Services; 2018.
  2. Hudson TJ, Edlund MJ, Steffick DE, Tripathi SP, Sullivan MD. Epidemiology of regular prescribed opioid use: Results from a national, population-based survey. J Pain Symptom Manage 2008; 36(3): 280–8.
  3. The Institute of Medicine. Relieving Pain in America: A Blueprint for Transforming Prevention, Care, Education, and Research. Washington, DC: The Institute of Medicine, National Academy of Sciences; 2011. Available at: http://www.iom.edu/Reports/2011/Relieving-Pain-in-America-A-Blueprint-for-Transforming-Prevention-Care-Education-Research.aspx
  4. Weeks WB, Pike J, Donath J, Fiacco P, Justice BD. Conservative spine care pathway implementation is associated with reduced health care expenditures in a controlled, before-after observational study. J Gen Intern Med 2019; 34(8): 1381–2.
  5. 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; 1(3): 226–33.
  6. Whedon JM, Toler AWJ, Goehl JM, Kazal LA. Association between utilization of chiropractic services for treatment of lowback pain and use of prescription opioids. J Altern Complement Med 2018; 24(6): 552–6.