Patients with back pain that has persisted for less than 12 weeks have a high probability of substantial pain reduction over time, but patients with back pain that has persisted for 12 or more weeks have a lower chance of improvement, new data suggest.
Patients with persistent pain (ie, pain lasting for more than 12 weeks but less than 52 weeks) had smaller improvements at 52 weeks, however.
“The outcomes for acute pain are better than we thought they were,” study author Lorimer Moseley, AO, DSc, PhD, professor of clinical neurosciences and chair of physiotherapy at the University of South Australia in Adelaide, told this news organization.
The study was published in the Canadian Medical Association Journal.
Good Prognoses
The current analysis represents an update to and advance on a 2012 systematic review and meta-analysis, said Moseley. That study found that patients with subacute low back pain and those with persistent low back pain had similar decreases in pain over 6 weeks. The previous analysis “may have resulted in improved outcomes in the persistent group,” the investigators wrote in the current analysis.
For the current study, the researchers examined 95 studies to understand the clinical course of acute, subacute (ie, lasting for 6 to less than 12 weeks), and persistent low back pain. They excluded retrospective cohorts and interventional studies, as well as studies of patients with low back pain for more than 12 months. The researchers also conducted meta-analyses on aggregate data, where possible, using pain and disability outcome data.
In patients with acute pain, the mean pain score improved from 56 at baseline to 26 at 6 weeks and 21 at 52 weeks. Patients with subacute pain had a mean pain score of 63 at baseline that improved to 29 at 6 weeks and was maintained at 31 at 52 weeks. Patients with persistent pain had a mean pain score of 56 at baseline that improved to 48 at six weeks and 40 at 52 weeks.
“I don’t think we need to do any more studies to clarify recovery from acute back pain,” said Dr. Moseley. “For subacute back pain, I think there is a moderate to high level of certainty, so the prognosis is pretty good there. The bad news is that the data suggest that if someone’s got back pain 3 months after onset, the likelihood of recovery is much less, but those data are the ones we can’t be certain of on the basis of this meta-analysis.”
Dr. Moseley noted that the current analysis is not highly detailed, because individual patient data are absent. This is “the biggest limitation from a methodological perspective,” he said. “Individual patient analysis is a lot more powerful.”
Comprehensive Literature Search
Commenting on the findings for this news organization, David Borenstein, MD, clinical professor of rheumatology at the George Washington University Medical Center and partner at Arthritis and Rheumatism Associates in Washington, DC, described the literature search as comprehensive. Dr. Borenstein did not participate in the study. The assessment of low back pain as either short-lived or lasting is worth investigating, he added, given that low back pain impairs a patient’s function and carries a hefty price tag at a societal level.
The study results suggest “that people with acute low back pain do pretty well, and people with subacute low back pain will do less well but still have a chance of healing,” said Dr. Borenstein. “People who have chronic low back pain do not do as well, and they have some increase in disability.” It would be important to develop ways to identify patients whose low back pain will persist beyond 3 months, as well as ways to identify the criteria or characteristics that might prevent those patients from having prolonged difficulties and persistent low back pain, he added.
Dr. Borenstein noted that the authors failed to mention specific approaches that could decrease progression from subacute to persistent low back pain. “They really don’t point anyone in a direction to what would make a difference,” he said. “It would have really improved the impact of the paper if they had seen anything along the way in their review of these articles that might have suggested how someone or a group might have been able to impact this progression.”
The study was funded by supported by a National Health and Medical Research Council Leadership Investigator Grant to Dr. Moseley. Dr. Moseley and Dr. Borenstein reported no relevant disclosures.
A version of this article appeared on Medscape.com.