Low back pain (LBP) is one of the main reasons for people consulting their general practitioner and seeking treatment from a physiotherapist. The provision of accurate advice on the recovery for LBP is an important feature of any consultation, yet there is disagreement as to its prognosis. Therefore, it was with great interest that I came across a systematic review with meta-analysis by Menezes Costa et al (2012) on the clinical course of pain and disability in patients with both acute and persistent LBP. Perhaps this could shed some light on the issue.
Here’s what they did
The authors searched MEDLINE, CINAHL and Embase databases from 1950 to November 2011. The search strategy used the study population terms suggested by the Cochrane Back Review Group together with a strategy for searching MEDLINE for prognosis studies. They included studies that were prospective cohort studies and that included a well-defined inception cohort (episode inception) of participants with LBP.
Specifically, they included studies that had (a) acute and sub-acute LBP cohorts that included participants with non-specific LBP of less than 12 weeks duration and/or (b) persistent LBP cohorts that included participants with non-specific LBP for more than 12 weeks but less than 12 months. For inclusion, the studies had to report pain or disability outcomes or a global measure of recovery.
Here’s what they found
43 articles reporting 33 cohorts (11,166 participants) met all criteria and were included in the review.
- In relation to the pain scores for patients with acute pain, the variance-weighted mean pain score (out of a maximum score of 100) was 52 (95% CI 48–57) at baseline, 23 (95% CI 21–25) at 6 weeks, 12 (95% CI 9–15) at 26 weeks and 6 (95% CI 3–10) at 52 weeks after the onset of pain.
- Among cohorts with persistent pain, the variance-weighted mean pain score (out of 100) was 51 (95% CI 44–59) at baseline, 33 (95% CI 29–38) at 6 weeks, 26 (95% CI 20–33) at 26 weeks and 23 (95% CI 16–30) at 52 weeks after the onset of pain.
- By one year, the average levels of pain and disability for acute LBP were low (mean pain score of 6 and disability score of 13), suggesting that patients can expect to have minimal pain or disability at one year.
- Patients with persistent LBP could expect to have moderate levels of pain and disability at 12 months (mean pain and disability scores of 23 and 17, respectively).
The authors concluded
This review confirms the broad finding of previous reviews that the typical course of acute LBP is initially favourable, i.e. there is a marked reduction in mean pain and disability in the first six weeks.
Beyond six weeks, improvement slows and, thereafter, only small reductions in mean pain and disability are apparent up to one year.
People with persistent LBP also experienced substantial improvement in the first six weeks, but there were only very small reductions in average pain and disability between 6 and 52 weeks.
A major strength of this review was the fact that only inception cohort studies were included, because this type of design minimises bias in studies of prognosis.
The Musculoskeletal Elf’s view
In this review it was found that patients who presented with acute or persistent LBP improved markedly in the first six weeks and after that time improvement slowed. Low to moderate levels of pain and disability were still present at one year, especially in the cohorts with persistent pain.
This type of information is important for clinicians to know so that they can provide accurate information to their patients on their expected course of recovery. It also raises the question as to whether or not it is worthwhile seeing patients for treatment in the early stages of LBP if the majority are better by 12 weeks. However, perhaps the individuals who then develop persistent LBP could be prevented from doing so if accurate advice and information were provided at its first onset.
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Menezes Costa, L.d.C., Maher, C.G., Hancock, M.J., McAuley, J.H., Herbert, R.D. & Costa, L.O.P. 2012, “The prognosis of acute and persistent low-back pain: A meta-analysis”, Canadian medical association journal, Vol. 184, no. 11, pp. E613-E624.
This is a really interesting bit of information. The one thing I was wondering about was what interventions these patients received in the first 6 weeks? Did any of these see a Physiotherapist or were they given drugs and information leaflet only? You would expect that to have an impact on outcome as well?
Acute pain might be mild and last just a moment, or it might be severe and last for weeks or months. In most cases, acute pain does not last longer than six months, and it disappears when the underlying cause of pain has been treated or has healed. Unrelieved acute pain, however, might lead to chronic pain.