A Mostly Uninformative Back Pain Trial in JAMA

There were almost 3 million visits to U.S. Emergency Departments last year for low back pain – and, yet, it is fair to say we manage these visits poorly.  Patients typically continue to have pain at discharge, at long-term follow-up, and we inject a vast number of opiates into circulation in the course of treatment.

This trial, appropriately, looks at a few of our most common prescriptions: scheduled NSAID (naprosyn), an anticholinergic smooth-muscle relaxant (cyclobenzaprine), and an opiate (oxycodone-acetaminophen).  Patients presenting to Montefiore hospital in the Bronx were randomized into three arms, and medications distributed in placebo-controlled, blinded fashion.

However, the primary outcome was not exactly what you might expect.  These authors used a questionnaire describing functional impairment, and used the change in impairment from enrollment to 1 week as their primary outcome.  This is an interesting choice as, while it doesn’t encounter some of the subjectiveness of pain scales, level of function is a technically surrogate outcome for pain relief.  Then, since it can be reasonably suggested the simple passage of time is the curative element in most cases of acute low back pain, it reasonable to expect such disability to regress to the mean, regardless of therapy, by one week.  I wonder if these authors did not inadvertently choose an outcome likely to show no difference.

And, that is precisely what they found.  At 1 week and – in another odd timeframe choice – 3 months.

However, that’s not the entirety of the story.  They measured many different outcomes, including adherence, utilization of the as-needed study medication, desire for same medication, days of return to work, and self-reported pain.  None of these secondary outcomes can be parsed reliably, but the general signal throughout is one of increased relief with the use of opiates.  It should be noted the authors’ conclusion is worded carefully – simply stating these data “do not support the use” of the therapies tested.  I am all for the avoidance of opiates, but the outcome measurement in this study probably obfuscates any potential benefit, and may rather mask their utility.

Lastly, these authors screened 2,588 patients with a complaint of low back pain in order to identify 390 meeting their inclusion criteria.  Radicular pain, traumatic pain, long-standing back pain, and elderly patients were all excluded – and, clearly, make up the bulk of visits to the Emergency Department.  These data apply to only a very small subset of patients, and they were enrolled at a single center.  The generalizability of their findings is not ideal.

It’s not a sexy topic, but its prevalence certainly makes it an important one.  If a fraction of the hundreds of millions of dollars devoted to the development of me-too blockbuster copycat drugs were devoted to such common issues, we would have far better data to guide the bulk of our practice.  I love that these authors did this trial – I just wish their measurements and timeframes differed.

“Naproxen With Cyclobenzaprine, Oxycodone/Acetaminophen, or Placebo for Treating Acute Low Back Pain: A Randomized Clinical Trial”