Opioid analgesia for acute low back pain and neck pain (the OPAL trial): a randomised placebo-controlled trial

Key Points

1. Opioids plus guideline-recommended care for acute low back pain and neck pain were no more effective for pain at six weeks than placebo plus guideline-recommended care.
2. The placebo group had slightly less pain at 12 months, and the opioid group had a slightly higher risk of misuse.

BACKGROUND & OBJECTIVE

Opioid analgesics are a common treatment for acute low back pain and neck pain, but there is limited evidence on their efficacy. Clinical guidelines recommend opioid analgesics for people with acute low back or neck pain only when other pharmacological treatments are contraindicated or have not worked. Despite these guidelines, as high as two thirds of people in Australia receive an opioid as first-line treatment when presenting for care with low back pain and neck pain. However, opioids for acute low back pain and neck pain is not supported by direct and robust evidence.

This randomized controlled trial examined the efficacy and safety of a short course of an opioid analgesic for acute low back pain and neck pain.

Opioid analgesics are a common treatment for acute low back pain and neck pain, but there is limited evidence on their efficacy.

Clinicians should advise clients with acute low back and neck pain that opioids should not be used as a treatment.

METHODS

• The study recruited 347 patients with less than 12 weeks of low back pain and/or neck pain.

• Participants were randomly assigned to six weeks of care in one of two groups: (1) guideline-recommended care plus an opioid (oxycodone–naloxone, up to 20 mg oxycodone per day orally) or (2) guideline-recommended care and a placebo.

• The primary outcome was pain severity at 6 weeks measured on a 10-point scale. There were numerous secondary outcomes, including function, mental health, health-care consumption, time missed from work, risk of misuse, and symptoms related to opioid side-effects like nausea or constipation.

RESULTS

• Of the 347 patients in the study, 58 discontinued before six weeks, with 33 from the opioid group and 25 from the placebo group.

• At six weeks, there were no significant differences in pain severity between the opioid and placebo groups (see Figure 1).

• Regarding the secondary outcomes, there were either no differences or small differences favoring the placebo group. For example, the placebo group had slightly less pain at 52 weeks, and the opioid grip had a slightly higher risk of misuse.

• The authors concluded that opioids should not be recommended for acute low back pain or neck pain.

LIMITATIONS

• Approximately 25% of the data was missing at six weeks, which reduced the power of the trial and could have introduced bias if the data was not missing at random.

• Only 58% of the participants reported their compliance with the medication regimen. However, this figure did not differ between the groups, and this likely reflects real world practice.

• The study failed to collect data on what guideline-recommended care was offered to participants in both groups.

• The study involved one specific form of opioid medication, and the results may not generalize to other opioid medications.

CLINICAL IMPLICATIONS

Low back pain and neck pain are two of the most costly medical problems in the world in terms of disability, medical expense, and overall economic burden (1,2).

Opioid analgesics can reduce pain, but also present risks of misuse and addiction (3). Further, numerous groups, such as the US Centers for Disease Control and Prevention, and the National Institute for Health and Care Excellence in the UK, have called for reductions in the use of opioids (4).

Despite these recommendations the use of opioids as a treatment for low back and neck pain remains extremely common.

This study found that this opioid plus guideline-recommended care provided no benefit compared to placebo plus guideline-recommended care, and in several ways performed worse.

Clinicians should advise clients with acute low back and neck pain that opioids should not be used as a treatment. Clinicians should be advising non-pharmacological treatments such as engaging in tolerable physical activity, learning self-management strategies and psychological therapy while reassuring the patient regarding prognosis of the pain. Simple over the counter analgesics such as non-steroidal anti-inflammatory drugs may be useful if necessary and there are no contraindications.

+STUDY REFERENCE

Jones C, Day R, Koes B, Latimer J, Maher C, McLachlan A, Billot L, Shan S, Lin C, OPAL Investigators Coordinators (2023) Opioid analgesia for acute low back pain and neck pain (the OPAL trial): a randomised placebo-controlled trial. Lancet, Epub ahead of print.

SUPPORTING REFERENCE

1. Vos T, Lim SS, Abbafati C, et al. Global burden of 369 diseases and injuries in 204 countries and territories, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019. Lancet 2020; 396: 1204–22.
2. Wu A, March L, Zheng X, et al. Global low back pain prevalence and years lived with disability from 1990 to 2017: estimates from the Global Burden of Disease Study 2017. Ann Transl Med 2020; 8: 299.
3. Chiarotto A, Koes BW. Nonspecific low back pain. N Engl J Med 2022; 386: 1732–40.
4. Humphreys K, Shover CL, Andrews CM, et al. Responding to the opioid crisis in North America and beyond: recommendations of the Stanford–Lancet Commission. Lancet 2022; 399: 555–604.