Rapidity and modality of imaging for acute low back pain in elderly patients.

BACKGROUND: Most quality metrics focus on underuse of services, leaving unclear what factors are associated with potential overuse. METHODS: We analyzed Medicare claims from 2000-2002 and 2004-2006 for 35 039 fee-for-service Medicare beneficiaries with acute low back pain (LBP) who were treated by 1 of 4567 primary care physicians responding to the 2000-2001 or 2004-2005 Community Tracking Study Physician Surveys. We modified a measure of inappropriate imaging developed by the National Committee on Quality Assurance. We characterized the rapidity (