Potential risk factors for recurrence of low back pain identified

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A study published by The Spine Journal has examined risk factors for recurring low back pain, identifying disc degeneration, the presence of high intensity zone and the number of previous episodes as potentially important risk factors.

“Studies of the course of low back pain have reshaped the contemporary view of this common, disabling and costly condition,” write the study the authors, led by Mark Hancock, Macquarie University, Sydney, Australia. “We now know that while most people recover quickly from an episode of low back pain, many will go on to have an unpredictable pattern of recurrent symptomatic episodes which are responsible for much of the burden of the condition. The rates of one-year recurrence reported in the literature range from 25% to 80%. Preventing these recurrences would be a major breakthrough but currently there is a lack of strong evidence for any effective preventative approach.”

The authors conducted a prospective inception cohort study with one-year follow up involving 76 people who had recovered from an episode of low back pain within the previous 10 months, in a bid to better understand the effects of lumbar pathology on low back pain recurrence rates. The primary outcome was the time to recurrence of low back pain which was determined by contacting participants at two-month intervals for 12 months.

All participants underwent a baseline assessment including magnetic resonance imaging (MRI) scan and completion of a questionnaire which assessed a range of potential risk factors for recurrence. MRI scans were reported for the presence of a range of MRI findings. The primary analysis investigated the predictive value of two clinical features (age and number of previous episodes) and six MRI findings (disc degeneration, high intensity zone, Modic changes, disc herniation, facet joint arthrosis and spondylolisthesis) in a multivariate Cox regression model. The authors decided that dichotomous predictors with hazard ratios of >1.5 or

“Of the eight predictors entered into the primary multivariate model, three—disc degeneration, high intensity zone and number of previous episodes—met our a priori threshold for potential importance,” the authors report. Participants with a disc degeneration score of >3 on the Pfirrmann scale had a hazard ratio of 1.89 (95% confidence interval 0.42 to 8.53) compared to those without. Patients with high intensity zone had a hazard ratio of 1.84 (95% confidence interval 0.94 to 3.59) compared to those without. For every additional previous episode participants had a hazard ratio of 1.04 (95% confidence interval 1.02 to 1.07).

“We identified promising risk factors for a recurrence of low back pain, which should be further investigated in larger trials,” write Hancock and colleagues. “The findings suggest pathology seen on MRI plays a potentially important role in recurrence of low back pain.”