Evidence for Anchoring Bias During Physician Decision-Making

Introduction: Cognitive biases are hypothesized to influence physician decision-making, but large-scale evidence consistent with their influence is limited. One such bias is anchoring bias, or the focus on a single-often initial-piece of information when making clinical decisions without sufficiently adjusting to later information. Objective: To examine whether physicians were less likely to test patients with congestive heart failure (CHF) presenting to the emergency department (ED) with shortness of breath (SOB) for pulmonary embolism (PE) when the patient visit reason section, documented in triage before physicians see the patient, mentioned CHF. Design, Setting, and Participants: In this cross-sectional study of 2011 to 2018 national Veterans Affairs data, patients with CHF presenting with SOB in Veterans Affairs EDs were included in the analysis. Analyses were performed from July 2019 to January 2023. Exposure: The patient visit reason section, documented in triage before physicians see the patient, mentions CHF. Main Outcomes and Measures: The main outcomes were testing for PE (D-dimer, computed tomography scan of the chest with contrast, ventilation/perfusion scan, lower-extremity ultrasonography), time to PE testing (among those tested for PE), B-type natriuretic peptide (BNP) testing, acute PE diagnosed in the ED, and acute PE ultimately diagnosed (within 30 days of ED visit). Results: The present sample included 108 019 patients (mean SD age, 71.9 10.8 years; 2.5% female) with CHF presenting with SOB, 4.1% of whom had mention of CHF in the patient visit reason section of the triage documentation. Overall, 13.2% of patients received PE testing, on average within 76 minutes, 71.4% received BNP testing, 0.23% were diagnosed with acute PE in the ED, and 1.1% were ultimately diagnosed with acute PE. In adjusted analyses, mention of CHF was associated with a 4.6 percentage point (pp) reduction (95% CI, -5.7 to -3.5 pp) in PE testing, 15.5 more minutes (95% CI, 5.7-25.3 minutes) to PE testing, and 6.9 pp (95% CI, 4.3-9.4 pp) more BNP testing. Mention of CHF was associated with a 0.15 pp lower (95% CI, -0.23 to -0.08 pp) likelihood of PE diagnosis in the ED, although no significant association between the mention of CHF and ultimately diagnosed PE was observed (0.06 pp difference; 95% CI, -0.23 to 0.36 pp). Conclusions and Relevance: In this cross-sectional study among patients with CHF presenting with SOB, physicians were less likely to test for PE when the patient visit reason that was documented before they saw the patient mentioned CHF. Physicians may anchor on such initial information in decision-making, which in this case was associated with delayed workup and diagnosis of PE.