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What's the Role of NSAIDs in Back Pain?

— Meta-analysis says "minimal" but diagnosis can confound

MedpageToday

Nonsteroidal anti-inflammatory drugs (NSAIDs) were only minimally effective for spinal pain, an Australian meta-analysis suggested.

Changes in spine pain with NSAIDs over the immediate term (less than 2 weeks) and short-term (2 weeks to 3 months) had a mean difference of -9.2 (95% CI -11.1 to -7.3) and -7.7 (95% CI -11.4 to -4.1), respectively, compared with placebo, according to a PhD student at the University of Sydney in New South Wales, and colleagues.

Action Points

  • Nonsteroidal anti-inflammatory drugs (NSAIDs) do not provide a clinically important effect on spinal pain compared to placebo, and six patients must be treated with NSAIDs for one patient to achieve a clinically important benefit in the short-term, according to an Australian meta-analysis.
  • Note that this result and those from recent reviews on paracetamol and opioids, indicate that the three most widely used and guideline-recommended medicines for spinal pain do not provide clinically important effects over placebo.

This did not meet the 10-point minimum threshold (on a 100-point scale) for a clinically important difference, they reported online in .

A limitation of the analysis was that it did not address the diverse causes for back pain, pointed out , of the departments of rehabilitation medicine, anesthesiology, perioperative care, and pain medicine at NYU Langone Medical Center in New York City.

"Every few years a study like this pops up saying that there's little or no help for back pain with NSAIDs, acetaminophen, surgery, injections, physical therapy, or yoga," Kim told 鶹ý.

"My belief is that back pain is very complex, probably one of the most complex things that we see in medicine, because it can be due to a whole slew of things, whether it's inflammatory, a muscle pull, a mechanical problem, or arthritis in the spine. There are whole textbooks on the diagnosis of back pain -- it's a very nebulous diagnosis," said Kim.

The Meta-Analysis

In the past, clinical guidelines have recommended acetaminophen as first-line treatment for back pain, NSAIDs second, and opioids third.

However, recent studies have demonstrated that acetaminophen lacks efficacy for spinal pain and opioids have minimal effects. For NSAIDs, the evidence for efficacy has been uncertain, and concerns about cardiovascular and gastrointestinal safety persist.

To clarify the role for NSAIDs in spinal pain -- a major cause of disability worldwide -- Machado's group conducted a systematic literature review in which they identified 35 randomized, placebo-controlled trials of non-selective NSAIDs and COX-2 inhibitors for neck pain, acute or chronic low back pain, and sciatica.

The median treatment duration in the included studies was 7 days, and most of the trials evaluated oral medications. The pooled data from all trials was considered moderate in quality.

For effects on disability, the immediate term change was -8.1 (95% CI -11.6 to -4.6), and short-term change was -6.1 (95% CI -9.5 to -2.8), again not meeting the threshold for a clinically important difference.

The number needed to treat for a clinically significant change in pain was five for the immediate term and six for the short term. In other words, "for every six patients treated with NSAIDs rather than placebo, only one additional patient would benefit considering a between-group difference of 10 points for clinical importance in the short term," the authors explained.

Quality of life was assessed on the Short Form-36 Health Survey physical and mental components. For the physical score, the mean change was -2.9 (95% CI -3.7 to -2.1), and no effect at all was seen on the mental score.

For safety, the analysis included 21 trials, again with a median treatment duration of a week. The overall risk of adverse events did not differ between NSAIDs and placebo (RR 1.1, 95% CI 1-1.2). However, patients using NSAIDs had a significantly greater likelihood of experiencing gastrointestinal events (RR 2.5, 95% CI 1.2-5.2).

Eight of the studies compared the use of rescue medications, with four showing that patients taking NSAIDs required additional analgesics, with a difference that was "arguably not clinically important," according to the authors.

On secondary exploratory analyses, they found that larger changes were seen in studies considered to have low risk of selection bias, and that the effects were greater for COX-2 inhibitors (-13.4, 95% CI -15.7 to -11.1) than for nonselective NSAIDs (-7.7, 95% CI -9.8 to -5.6). However, this difference was "of questionable clinical relevance," Machado's group stated.

"There is an urgent need to develop new analgesics for spinal pain," they concluded.

A limitation of the analysis was its lack of evidence for longer-term effects with NSAIDs.

A Diagnostic Challenge

"It's very challenging as a clinician to really find the exact diagnosis," Kim cautioned.

"It's not like a cataract in the eye, where it's either a cataract or not. You're dealing with patients with stenosis, degenerative disks and facet joints, muscle issues, and radiculopathy. Obviously, if you take this big mix of diagnoses and give them something like an NSAID, you're going to have some people who don't respond and some who respond very well," he said.

"My approach to treating the spine is to offer many different types of therapy with the hope that there's something they will respond to. If the pain is inflammatory, they may respond to an NSAID, but if it's non-inflammatory, they might need a muscle relaxant or something else," he said.

Another option might be acupuncture, according to Kim, who is also a trained acupuncturist. "I've had patients who didn't respond to NSAIDs, surgery, or physical therapy but who did respond to acupuncture," he said.

"Essentially, I'd recommend that if you're trying something and it doesn't help, refer the patient to a spine center or pain management specialist," he advised.

Disclosures

Machado and a co-author disclosed support the Department of Education and Training of Australia. Two co-authors disclosed support from the National Health and Medical Research Council and the Sydney Medical School.

Machado and co-authors disclosed no relevant relationships with industry.

Primary Source

Annals of the Rheumatic Diseases

Machado G, et al "Nonsteroidal anti-inflammatory drugs for spinal pain: a systematic review and meta-analysis" Ann Rheum Dis 2017; DOI: 10.1136/annrheumdis-2016-210597.