Study objectives: We sought to determine whether the accuracy of pretest assessment of the likelihood of pulmonary embolism (PE) was related to physician experience. We compared the accuracy of the subjective pretest probability assessment made by senior physicians (postgraduate year [PGY]-4+) to that of interns (PGY-1) and residents (PGY-2 and PGY-3) working in the emergency department of a large teaching hospital.
Design: Prospective observational study.
Setting: Urban, academic emergency department with an annual census of 48,000 patient visits.
Patients: Five hundred eighty-three adults evaluated for PE in the emergency department.
Interventions: Eligible patients had at least one diagnostic test ordered to workup PE. The physician treating the patient was asked whether he or she considered PE the most-likely diagnosis or whether an alternative diagnosis was most likely. This result was compared to the ultimate diagnosis. Physician experience was categorized by the number of years of training since medical school graduation.
Measurements and results: There was a trend toward increasing accuracy with increasing experience, demonstrated by the frequency of true-positive assessments (17% vs 20% vs 25%), true-negative assessments (89% vs 94% vs 96%), and likelihood ratio (1.49 vs 2.34 vs 3.33), respectively.
Conclusions: Accurate determination of the pretest probability of PE appears to increase with clinical experience. However, the difference in accuracy between inexperienced and experienced physicians is not sufficiently large to distinguish between the two when determining whether clinical gestalt or a clinical prediction rule should be used to determine the pretest probability of PE.