Patient characteristics associated with diagnostic imaging evaluation of persistent low back problems

Study Design. Post hoc analysis of data from the National Low Back Pain Study, a prospective observational multicenter study of patients referred for the evaluation and treatment of persistent low back problems. Objective. To identify patient characteristics associated with use of particular diagnostic imaging examinations in patients with persistent low back problems. Summary of Background Data. The Agency for Health Care Policy and Research clinical practice guidelines on low back problems suggest that the use of particular diagnostic imaging tests for a given patient should be based on specific characteristics of that patient. Methods. Use of diagnostic imaging examinations in 2,374 patients with persistent low back problems who were enrolled in the National Low Back Pain Study from 1986 to 1991 was analyzed. Stepwise logistic regression was used to identify patient characteristics that distinquish between enrollees who underwent particular imaging studies. Results. Characteristics that distinguished patients who had undergone magnetic resonance imaging from those who had received only lumbo-sacral spine radiographs included higher socioeconomic status, greater resource use in the preceding 12 months, more functional impairment, presence of sciatica, and presence of neurologic signs/symptoms suggestive of nerve root compromise. Suspected soft tissue involvement was characteristic of enrollees who had undergone magnetic resonance imaging, whereas suspected structural involvement characterized patients who received noncontrast computed tomography. Only nonclinical factors, such as higher annual household income, disability compensation, and male gender distinguished enrollees who had undergone both magnetic resonance imaging and computed tomography-myelography from those who received only computed tomography-myelography. Conclusion. Particular patient socioeconomic and clinical characteristics are associated with receipt of specific imaging studies in evaluation of persistent low back problems.