MONDAY, June 22, 2015 (HealthDay News) -- 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, M.D., 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 percent 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 percent probability of chronic pain as the cutoff for low risk and greater than 40 percent 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."