The results of this paper are hardly surprising, since the witnessed phenomenon – “anchoring bias” – exists as defined. However, it’s always fun to see it demonstrated objectively.
In this little piece of research, authors collated four years of encounters to Veterans Affairs emergency departments in the U.S. and parsed out the triage reason between “congestive heart failure” versus all others. These two groups were then compared regarding the rates of objective testing for pulmonary embolism, frequency of ordering B-type natiuretic peptide, and both initial and 30-day diagnoses of pulmonary embolism.
As the title suggests, the authors identify differences in testing associated with the recorded reason for visit – with less frequent testing for PE, increased confirmatory testing for CHF, and fewer diagnoses of PE at the initial visit. However, the 30-day rate of diagnosis for PE was the same between the two groups – 1.2% in those initially presenting for reason of CHF, and 1.1% for all others.
The implication suggested by these authors is the subsequent similar frequency of PE at 30 days represent a delayed or missed initial diagnosis, with the culprit being an element of cueing from the patient triage reason or other elements of medical history. This is obviously not a study design with the ability to conclusively demonstrate such a causative effect; a prospective design randomizing patients with an initial “CHF” reasons for visit to an alternative such as “shortness of breath” would tease out this effect. That said, this likely still represents an undercurrent of anchoring bias.
“Evidence for Anchoring Bias During Physician Decision-Making”
https://jamanetwork.com/journals/jamainternalmedicine/article-abstract/2806464