High physician concern about malpractice risk predicts more aggressive diagnostic testing in office-based practice.

Despite widespread agreement that physicians who practice defensive medicine drive up health care costs, the extent to which defensive medicine increases costs is unclear. The differences in findings to date stem in part from the use of two distinct approaches for assessing physicians' perceived malpractice risk. In this study we used an alternative strategy: We linked physicians' responses regarding their levels of malpractice concern as reported in the 2008 Health Tracking Physician Survey to Medicare Parts A and B claims for the patients they treated during the study period, 2007-09. We found that physicians who reported a high level of malpractice concern were most likely to engage in practices that would be considered defensive when diagnosing patients who visited their offices with new complaints of chest pain, headache, or lower back pain. No consistent relationship was seen, however, when state-level indicators of malpractice risk replaced self-rated concern. Reducing defensive medicine may require approaches focused on physicians' perceptions of legal risk and the underlying factors driving those perceptions.