Friday, May 1, 2015

Is There a Baby in That Bathwater? Status Quo Bias in Evidence Appraisal in Critical Care

"But we are not here concerned with hopes and fears, only the truth so far as our reason allows us to discover it."  -  Charles Darwin, The Descent of Man

Status quo bias is a cognitive decision making bias that leads to decision makers' preference for the choice represented by the current status quo, even when the status quo is arbitrary or irrelevant.  Decision makers tend to perceive a change from the status quo as a loss and therefore their decisions are biased toward the status quo.  This can lead to preference reversals when the status quo reference frame is changed.  The status quo can be debiased using a reversal test, i.e., manipulating the status quo either experimentally or via thought experiment to consider a change in the opposite direction.  If reluctance to change from the status quo exists in both directions, status quo bias is likely to exist.

My collaborators Peter Terry, Hal Arkes and I reported in a study published in 2006 that physicians were far more likely to abandon a therapy that was status quo or standard therapy based on new evidence of harm than they were to adopt an identical therapy based on the same evidence of benefit from a fictitious RCT (randomized controlled trial) presented in the vignette.  These results suggested that there was an asymmetric status quo bias - physicians showed a strong preference for the status quo in the adoption of new therapies, but a strong preference for abandoning the status quo when a standard of care was shown to be harmful.  Two characteristics of the vignettes used in this intersubject study deserve attention.  First, the vignettes described a standard or status quo therapy that had no support from RCTs prior to the fictitious one described in the vignette.  Second, this study was driven in part by what I perceived at the time was a curious lack of adoption of drotrecogin-alfa (Xigris), with its then purported mortality benefit and associated bleeding risk.  Thus, our vignettes had very significant trade-offs in terms of side effects in both the adopt and abandon reference frames.  Our results seemed to explain s/low uptake of Xigris, and were also consistent with the relatively rapid abandonment of hormone replacement therapy (HRT) after publication of the WHI, the first RCT of HRT.