A clinical decision rule (CDR) with eight items can classify patients with acute low back pain (LBP) by their risk for chronic pain, according to a study published in the July 1 issue of The Spine Journal.
Wolf E. Mehling, MD, from the University of California, San Francisco, and colleagues conducted a prospective cohort study of risk factors for the progression to chronic pain. Six hundred five patients with acute LBP (≥30 days’ duration) were included, and they were surveyed at baseline, six months, and two years.
The researchers found that 13% and 19% of the patients had chronic pain at six months and two years, respectively. An eight-item CDR was deemed most parsimonious for classifying patients into three risk levels. For the six-month CDR, the bootstrapped area under the curve was 0.76. There was an odds ratio of 11.1 for developing chronic pain for each 10-point score increase. Likelihood ratios were 0.26 and 4.4, respectively, using a less than 5% probability of chronic pain as the cutoff for low risk and greater than 40% probability for high risk.
“A CDR was developed that may help primary care clinicians classify patients with strictly defined acute LBP into low-, moderate-, and high-risk groups for developing chronic pain and performed acceptably in 1,000 bootstrapped replications,” the authors write. “Validation in a separate sample is needed.”