Clinical Decisionmaking

Back pain study examines pain intensity and functioning

Most episodes of low back pain (LBP) improve within 6 weeks or less of onset. Only 5 to 10 percent of patients with LBP have persistent symptoms, and only 2 percent have radiating leg pain; however, these patients account for 85 percent of medical care costs and disability compensation for LBP.

A recent study led by Richard Deyo, M.D., of the University of Washington and supported in part by the Agency for Healthcare Research and Quality (HS08194) suggests that assessing both the intensity of a person's LBP and the extent of radiating leg pain may indicate the actual impact of LBP on that person's ability to function, low back disability, and use of diagnostic imaging.

In this study, the researchers analyzed data from 563 outpatients with chronic low back pain in the Veterans Health Study who were stratified according to low, moderate, and high intensity, as well as LBP alone (group 1), LBP and less radiating leg pain (group 2), and LBP and extensive leg pain (group 3). They found that regardless of radiating leg pain, there was a steady decline in all four functional status scale scores from low (less than 40) to high (60 or greater) LBP intensity. Group 3 had the lowest mean physical and role functioning scores.

Regardless of radiating leg pain, there was a steady increase in the number of disability days, days of reduced activity, and days of work loss from group 1 to group 3. Finally, regardless of radiating leg pain, the proportion of patients having had a spine computerized tomography (CT) scan or spine magnetic resonance imagery (MRI) generally increased from low to high LBP intensity.

Moreover, in all three localized LBP intensity groups, group 3 patients with extensive radiating leg pain included a higher proportion of patients who had a spinal CT scan or MRI than group 2 or group 1 patients. The researchers conclude that localized LBP intensity and radiating leg pain may measure two different aspects of low back problems and may be complementary tools for assessing outcomes of patients with LBP.

See "Assessment of functional status, low back disability, and use of diagnostic imaging in patients with low back pain and radiating leg pain," by Xinhua S. Ren, Alfredo J. Selim, Graeme Fincke, and others, in the November 1999 Journal of Clinical Epidemiology 52(11), pp. 1063-1071.

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