Does acupuncture reduce opioid use?

Stimulated by Pham et al 2021.[1]

NSAIDs – non-steroidal anti-inflammatory drugs
PT – physical therapy
TENS – transcutaneous electrical nerve stimulation
ED – emergency department

key to acronyms

This is another large retrospective observational cohort trial, and the second I have highlighted studying opioid use from the US. The first looked at the initial healthcare provider in new cases of low back pain and the risk of ending up on opioid medication: Initial healthcare provider and opioid use in LBP?

This paper used data from a large commercial health insurance scheme active across the US. The team looked for claims for the use of acupuncture, NSAIDs or PT over a 4-year period from 2014 to 17 inclusive. The index date was set as the date of first use of acupuncture, NSAIDs or PT. They found just over 7.5 million cases. This cohort was reduced to 6.6 million by restricting the population to those 18 or over (age). It was further refined by selecting only patients with continuous medical and pharmacy coverage for 12 months before and after the index date. This left ~3.3 million. Patients with cancer were excluded, and the sample was restricted to those patients with a claim for neck or back pain, headache or migraine within 90 days prior to the index date. This left a cohort of 1.7 million.

The cohort was further refined by limiting it to patients without the index therapy within 12 months prior to the index date. Subsequent propensity score matching was performed between the cohort that received acupuncture with the larger cohort who received either NSAIDs or PT. This match was based on the following:

• age
• sex
• region
• payor type
• urban residence
• index year
• race/ethnicity
• median income
• education level
• Deyo Charlson Comorbidity score
• back pain
• joint pain
• fibromyalgia
• pelvic pain
• extremity pain
• injuries
• chiropractor use
• TENS use
• opioid use
• inpatient visits
• ED visits
• number of medications
• medical costs.

Greedy nearest neighbour

A greedy nearest neighbour technique was used for matching. This is an algorithm that chooses a treatment group (acupuncture) member and then chooses a control group (NSAIDs or PT) member that is the closest match.

In the end they finished up with 2 cohorts of 52 346 patients.

Fewer patients in the acupuncture group initiated opioids

Fewer patients in the acupuncture group initiated opioids whether they were those with (49.2% vs 56.5%, p<0.001) or without (15.9% vs 22.6%, p<0.001) baseline opioid use. The difference in percentage points here is quite similar at 7.3 and 6.7 respectively, but because the opioid naïve cohort was over 3 times larger, the absolute difference in patient numbers was 770 and 2735 respectively.

There was a small increase in invasive surgical procedures in the acupuncture cohort (3.1% vs 2.8%, p=0.006), so a 0.3% difference. This difference is probably not clinically relevant, although it is statistically significant due to the large numbers in the cohorts.

ED visits were lower in the acupuncture cohort (-4.3% for all causes, -3.3% for pain, p<0.001), although physician office visits were increased a little.

Acupuncture was associated with higher total medical and pharmacy costs (+$1331 per patient, p=0.006), but when acupuncture was compared with PT the mean difference was only $14.

So, does acupuncture reduce opioid use?

The answer is probably, but this paper demonstrates an association of acupuncture use with lower opioid consumption as compared with NSAID or PT use. It is observational, so no cause and effect relationship can be inferred, prospective research is needed for that, but it is certainly encouraging, with modest and believable results.

References

1          Pham T, Ma Q, Agiro A, et al. Do acupuncture services reduce subsequent utilization of opioids and surgical interventions compared to noninvasive therapies among patients with pain conditions? Pain Med Published Online First: 15 June 2021. doi:10.1093/pm/pnab187

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Declaration of interests MC