Association Between Chiropractic Spinal Manipulation and Gabapentin Prescription

Association Between Chiropractic Spinal Manipulation and Gabapentin Prescription in Adults with Radicular Low Back Pain: Retrospective Cohort Study Using US Data

BMJ Open

July 21, 2023; Vol. 13; No. 7; e073258

Robert J Trager, Zachary A Cupler, Roshini Srinivasan, Regina M Casselberry, Jaime A Perez, Jeffery A Dusek: this study cites 79 references.

This study was the first to examine the association between chiropractic spinal manipulative therapy (CSMT) and the likelihood of gabapentin prescription among patients with radicular low back pain (rLBP). Participants were adults aged 18–49 who were having their first episode of rLBP diagnosis. Their mean age was 36 years, and 60% were women.

Only patients with rLBP were included in this study, and this type of LBP often involves neuropathic pain.
[Article Review 22-24: Nerve Pathology and Neuropathic Pain After Whiplash Injury]

Exclusions included severe pathology such as malignancy, fracture, infection, and cauda equina syndrome. In addition, subjects with previous lumbar surgery, scoliosis, spondylolisthesis, lumbosacral plexopathy, myelopathy, fibromyalgia, and multiple sclerosis were excluded.

Eligible patients were from 77 healthcare organizations:

• There were 1,635 patients in the CSMT cohort.
• There were 1,635 patients in the gabapentin cohort.

The authors hypothesized that adults under 50 years of age receiving CSMT for newly diagnosed rLBP would have reduced odds of receiving a gabapentin prescription over a 1 year-follow-up.

Usual medical care was defined as a range of medical services besides CSMT, including physical therapy, medications, and interventional or surgical procedures.

KEY POINTS FROM THIS ARTICLE:

1) “The USA has the leading age-standardized prevalence of low back pain (LBP) in the world.”

2) “Together, low back and neck pain account for the leading cause of medical expenditures in the USA.”

3) “Radicular low back pain (rLBP) is often treated off-label with gabapentin or by chiropractors using chiropractic spinal manipulative therapy (CSMT).”

4) “Radicular low back pain (rLBP), which involves a nerve root lesion, is considered a type of neuropathic pain, and involves radiating symptoms into the ipsilateral lower extremity.”

• “Non-rLBP resulting from myofascial, discogenic, sacroiliac or zygapophyseal joint pain is considered nociceptive and does not necessarily radiate to the lower limb.”

5) “Gabapentin is an anticonvulsant, anti-epileptic medication, used as first-line therapy for several types of neuropathic pain including diabetic neuropathy and herpetic neuralgia.”

• “Gabapentin may alleviate neuropathic pain by binding to a subunit of voltage-gated calcium channels, subsequently inhibiting ectopic nerve discharges.”
• “Gabapentin has been used off-label to treat neuropathic symptoms of LBP, namely rLBP.”
• Gabapentin has had US Food and Drug Administration (FDA) approval for use in neuropathic pain conditions since 1993.
  • “Systematic reviews in 2018 and 2022 demonstrated clear evidence of lack of its effectiveness for rLBP.” [Important]
• There is growing evidence of risks associated with gabapentin use, including abuse, misuse, dependence, and withdrawal. [Important]
  • Other deleterious adverse effects of gabapentin include somnolence (excessive sleepiness), dizziness, ataxia, fatigue, and new-onset asthenic (weakness or lack of energy) symptoms.
• “Several clinical practice guidelines do not recommend gabapentin for the treatment of LBP or rLBP, including those of the American Family Physician.”
• “Gabapentin prescription for LBP has been described as a marker of low-value care and medical overuse.”
• “Despite the paucity of evidence, and in contrast to clinical guideline recommendations, gabapentin continues to be commonly prescribed for LBP.”

6) “Chiropractors are portal-of-entry providers in the USA who frequently treat spinal disorders.”

• “When treating rLBP, these providers often use chiropractic spinal manipulative therapy (CSMT), a hands-on treatment directed to the joints of the spine.” [Important]
• CSMT is supported by systematic reviews and recommended by clinical practice guidelines for the treatment of LBP and rLBP.

7) “Studies have found that the initial type of provider seen for LBP influences the subsequent likelihood of receiving a prescription for certain medications.”

• “Patients initiating care for LBP with a chiropractor compared with other providers have reduced odds of receiving an opioid or benzodiazepine prescription.” [Important]

8) Disc degeneration and spondylosis may cause axial LBP without radiculopathy.

9) “Neuropathic pain is more common in those with LBP related to lumbar disc herniation compared with lumbar stenosis, scoliosis or spondylolisthesis.”

10) “The age bracket of adults under 50 was selected [because] rLBP is more likely to result from lumbar disc herniation in patients of this age, while older patients are more likely to have lumbar stenosis underlying rLBP.”

11) The natural history of rLBP is that it typically improves over a span of 3 months to 1 year. [Important]

12) Findings:

• “Gabapentin prescription was less frequent in the CSMT cohort over the 1-year follow-up after rLBP diagnosis.”
• “After matching, odds of gabapentin prescription over the 1-year follow-up were significantly lower in the CSMT cohort compared with the cohort receiving usual medical care,” by 47%.

13) Conclusions:

• “These real-world findings support our hypothesis that adults initially receiving CSMT for rLBP have reduced odds of receiving a gabapentin prescription over a 1-year follow-up period.” [Key Point]
• “Our findings are similar to those of previous studies which demonstrated an association between initial receipt of CSMT and reduced odds of prescription of opioids and benzodiazepines.”
• “Our findings add to growing evidence that receipt of CSMT early in the care pathway for new onset LBP/rLBP could lead to greater concordance with these guidelines with respect to medication prescribing practices.”
• “Our findings are consistent with some authors’ recommendations that patients with LBP/rLBP should initiate treatment with non-pharmacological providers such as chiropractors.” [Key Point]
• “This large retrospective cohort study found that adults receiving CSMT for a new diagnosis of rLBP have significantly reduced odds of receiving a gabapentin prescription over 1-year follow-up compared with those receiving usual medical care.”

14) “Gabapentin, opioids and benzodiazepines are… not recommended by several clinical practice guidelines for acute LBP/rLBP.” [Important]

• Gabapentin carries a “risk of abuse, misuse, dependence, withdrawal and adverse events.”

15) Explanations as to why initial CSMT for rLBP could be associated with a reduction in gabapentin prescription include:

• “While US chiropractors are portal-of-entry providers, they do not prescribe medications, including gabapentin.”

16) “Considering that previous randomised controlled trials have found that CSMT is effective in alleviating LBP and rLBP, it remains possible that pain relief afforded by CSMT accounts for the observed reduction in gabapentin prescription.”

17) “[A] previous study found that patients who received CSMT for LBP had significantly reduced odds of having an adverse drug reaction suggesting that reduced prescription of medications used to treat pain could translate into less adverse events.” [Important]

18) “Based on previous literature regarding opioids, it is possible that initiating care for rLBP with any non-pharmacological provider (ie, physical therapist, acupuncturist, chiropractor) would similarly yield a reduction in prescribing of gabapentin.”

These Article Reviews support that chiropractic care reduces the use of opioids:

20-18: Chiropractic Services for Treatment of Low-Back Pain and Use of Prescription Opioids

48-18: Influence of Initial Provider on Health Care Utilization in Patients Seeking Care for Neck Pain

15-19: Opioid Use Among Veterans of Recent Wars Receiving Veterans Affairs Chiropractic Care

48-19: The Initial Healthcare Provider for New-onset Low Back Pain with Early and Long-term Opioid Use