Docs' confidence in diagnosis unrelated to diagnostic accuracy

(HealthDay)—Physicians' confidence in their diagnostic accuracy is not associated with actual diagnostic accuracy or with case difficulty, according to a study published online Aug. 26 in JAMA Internal Medicine.

Ashley N.D. Meyer, Ph.D., from the Houston Veterans Affairs Health Services Research and Development Center of Excellence and the Section of Health Services Research, and colleagues assessed the correlation between diagnostic accuracy and confidence in that accuracy (diagnostic calibration) in a vignette study involving 118 physicians. Participants were asked to diagnose four previously validated case vignettes (two easier, two more difficult) and to record their corresponding judgments of confidence.

The researchers found that the physicians correctly diagnosed 55.3 percent of easier and 5.8 percent of more difficult cases. The difference in confidence was relatively small (7.2 versus 6.4 out of 10 for easier and more difficult cases, respectively) and was probably clinically insignificant. More difficult cases had worse diagnostic calibration and were characterized by overconfidence in accuracy. There were decreased requests for additional diagnostic tests with higher confidence. There was a significant positive correlation between higher case difficulty and requests for additional reference materials.

"Our study suggests that the association between physicians' diagnostic accuracy and their confidence in that accuracy may be poor and that physicians may not request the required additional resources to facilitate diagnosis when they most need it," the authors write.