Opioid pain relievers do not reduce acute lower back and neck pain, study suggests

There was no significant difference in pain levels in patients with lower back or neck pain who were given opioid pain relievers compared to those given a placebo, according to a randomised controlled trial published in The Lancet.

Lower back and neck pain are very common worldwide. [1] Clinical guidelines currently recommend opioid pain relievers for patients where other treatments have failed or are contraindicated, but there are concerns around the strength of the evidence to support this recommendation. Evidence has also suggested that prescribing opioids for lower back and neck pain may be more liberal in practice—for example, international data suggests that around 40% of people with low back pain were prescribed opioid pain relievers. [2] Meanwhile, a study from Australia has suggested that as many as two-thirds of people who presented to hospital with lower back pain received opioid pain relievers. [3]

A significant concern around prescribing opioids for lower back and neck pain is the risks it carries around future dependence, misuse, and overdose. The Stanford-Lancet Commission on the opioid crisis in North America called for stricter opioid stewardship in clinical settings, to prevent overprescription, which it identified as a key driver of the U.S.'s opioid epidemic.[4] When it comes to lower back and neck pain, existing evidence looking at the efficacy of opioid pain relievers has so far found modest effects on pain levels in chronic populations only, and is limited to studies with short follow-up periods. This is the first randomised controlled trial to investigate the safety and efficacy of opioid pain relievers for acute lower back and neck pain with a follow-up period as long as one year.

Senior author on the study, Prof Christine Lin, University of Sydney, says "Despite there being no evidence of their efficacy in reducing pain, opioid pain relievers are still widely prescribed for people with lower back and neck pain in many countries. Our study now suggests that they could be making patients' pain levels worse in the medium and long term. As well as not providing patients with the pain relief intended, we also know that being prescribed opioid pain relievers even for a short period of time increases the risk of opioid misuse long term. Considering all the evidence and known risks, we firmly believe doctors should not prescribe opioid pain relievers for new episodes of lower back and neck pain." [5]

She continues: "Lower back and neck pain can severely impact patients' quality of life, so we need to offer them the best options to help manage their pain, but opioid pain relievers do not work and carry serious risks. Instead, doctors should be encouraged to focus on patient-centred approaches that could include advice to stay active, and simple pain relievers. The good news is most people with acute low back pain and neck pain recover within 6 weeks naturally." [4]

The study took place across 157 sites in Australia between 2016 and 2021. It included 347 participants who had already been experiencing lower back pain, neck pain, or both for up to 12 weeks. All participants received guideline care (reassurance and advice to stay active), while 174 were given opioid pain relievers and the other 173 were given a placebo for up to six weeks. The trial was blinded, so participants did not know whether they were given the opioid pain reliever or placebo. After six weeks of treatment, the participants were free to seek other care if required. Participants' pain severity was assessed, and adverse events were recorded, after the six weeks of treatment and again after one year. Their risk of susceptibility to opioid misuse were also measured using the Current Opioid Misuse Measure, which assesses key risk factors such as signs and symptoms of intoxication, emotional volatility, addiction, and problematic medication behaviour.

There was no significant difference in pain scores at six weeks between the opioid and placebo groups—with average pain scores out of 10 being 2.8 in opioid group compared to 2.3 in placebo group. At one year, the average pain scores in the placebo group were slightly lower—2.4 in opioid group compared to 1.8 in placebo group.

There was no difference in overall number of participants reporting an adverse event between treatment groups, however, there were more reports of nausea, constipation, and dizziness in the opioid group.

Participants in the opioid group had a greater risk of opioid misuse after one year. Risk of misuse was no different between groups after 12 and 26 weeks, but significantly higher in the opioid group after one year—with 20% (24/123) compared to 10% (13/128) scoring at risk on the Current Opioid Misuse Measure Scale.

After six months 15-20% of 119 participants with ongoing pain reported taking an opioid, and 25% of 106 participants with ongoing pain reported opioid use at week 52.

The authors note some limitations of their study. Approximately 25% of pain score data was missing at the end of the trial due to participants dropping out or being uncontactable. The authors performed additional analyses that demonstrated that the main outcomes were unlikely to be affected by the missing data. In addition, not all participants took the medication as prescribed. 57% of participants reported their compliance, and of those, just over half were compliant (taking more than 80% of prescribed medicines). However, it is important to note that compliance did not differ between the opioid and placebo group, is consistent with other drug trials in back pain, and may reflect real-world practice.

Writing in a Linked Comment, Prof Mark Sullivan and Prof Jane Ballantyne, University of Washington, who were not involved in this research, said, "The OPAL trial is a single trial, but it raises serious questions about the use of opioid therapy for acute low back and neck pain. Current clinical guidelines recommend opioids for patients with acute back and neck pain when other pharmacological treatments are contraindicated or have not worked. As many as two-thirds of patients might receive an opioid when presenting for care of back or neck pain. It is time to re-examine these guidelines and these practices."

More information:
Opioid analgesia for acute low back pain and neck pain (the OPAL trial): a randomised placebo-controlled trial, The Lancet (2023). www.thelancet.com/journals/lan … (23)00404-X/fulltext

Provided by Lancet