Patterns of ordering diagnostic tests for patients with acute low back pain. The North Carolina Back Pain Project

Ann Intern Med. 1996 Nov 15;125(10):807-14. doi: 10.7326/0003-4819-125-10-199611150-00004.


Background: Low back pain is a common reason for visiting a physician. Authors of guidelines and insurance payers are currently scrutinizing use of radiography and computed tomography (CT) or magnetic resonance imaging (MRI).

Objective: To study the determinants of the use of lumbar spine radiography and either CT or MRI in patients with acute low back pain.

Design: Prospective cohort study.

Setting: Community-based practices in North Carolina in six strata: urban primary care physicians, rural primary care physicians, urban chiropractors, rural chiropractors, orthopedic surgeons, and practitioners at a group-model health maintenance organization.

Patients: 1580 patients with acute low back pain.

Measurements: Telephone interviews done after the index office visit and at 2, 4, 8, 12, and 24 weeks or until complete recovery; survey of practitioners; and chart abstraction.

Results: During the acute back pain episode, 46% of patients had radiography and 9% had CT or MRI. Patient variables related to use of radiography included pain that began more than 2 weeks before the index visit and no previous episodes of low back pain. Practitioner variables associated with use of radiography were being a chiropractor or orthopedic surgeon and having a solo practice. Use of CT or MRI was associated with white race, neurologic deficit at baseline, sciatica, poor functional status at baseline, and small group-practice size. Practitioners' responses to clinical vignettes were associated with aggregate practitioner behavior: In the vignettes and in real life, practitioners were more likely to order CT for patients with sciatica. However, a practitioner's response to a vignette did not predict that practitioner's use of CT or MRI for similar patients in his or her own practice.

Conclusion: Radiography is commonly used as a diagnostic test for patients with acute back pain. Clinical factors and provider specialty are major correlates of the use of imaging studies.

Publication types

  • Case Reports
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acute Disease
  • Adult
  • Back Pain / ethnology
  • Back Pain / etiology*
  • Chiropractic
  • Chronic Disease
  • Family Practice
  • Female
  • Humans
  • Lumbar Vertebrae / diagnostic imaging*
  • Lumbar Vertebrae / pathology
  • Magnetic Resonance Imaging*
  • Male
  • North Carolina
  • Orthopedics
  • Practice Patterns, Physicians'*
  • Professional Practice
  • Prospective Studies
  • Sciatica / etiology
  • Tomography, X-Ray Computed*