The effect of C-reactive protein on chest X-ray interpretation: A decision-making experiment among pediatricians

Clinical decision-making is complex and requires the integration of multiple sources of information. Physicians tend to over-rely on objective measures, despite the lack of supportive evidence in many cases. We sought to test if pediatricians over-rely on C-reactive protein (CRP) results when managing a child with suspected pneumonia.

A nationwide decision-making experiment was conducted among 337 pediatricians in Israel. Each participant was presented with two detailed vignettes of a child with suspected pneumonia, each with a chest X-ray (CXR) taken from a real-life case of viral pneumonia. Participants were randomly assigned to one of three groups: Controls-where no lab tests were provided, and two intervention groups where the vignettes also noted a high or a low CRP value, in varying orders. Between-participant and within-participant analyses were conducted to study the effect of CRP on CXR interpretation. The three groups were presented with identical medical history, vital signs, findings on physical examination, blood count, and CXR.

Three-hundred and one pediatricians (89.3% of those approached) completed the study. Pediatricians were 60%-90% more likely to diagnose viral pneumonia as bacterial when presented with high CRP levels versus low CRP levels, despite the identical clinical data and CXR (62% vs. 39% and 58% vs. 31% of physicians; p = .002). Accordingly, they were 60%-90% more likely to prescribe antibiotics in these cases (86% vs. 53% and 78% vs. 41% of physicians; p < .001).

CRP by itself may modify the way in which pediatricians interpret a CXR, leading to the overprescription of antibiotics.