Age-bias in assessments of medical decision-making capacity: a cross-sectional experimental vignette study

Accurate assessments about medical decision-making capacity (DMC) are vital but could be susceptible to age-bias. We examined if client age impacts on DMC likelihood assessment. One hundred and forty-seven adults were trained to identify four cognitive abilities (i.e., understanding, appreciation, reasoning, expression). Six experimental vignettes described a person making a diabetes treatment decision with systematic variation of client age (unspecified, 50-, or 95-years-old) and abilities (demonstrated vs uncertain). The dependent variable was DMC likelihood. Standardised tests of explicit (Kogan's Attitudes Toward Old People scale) and implicit age-bias (IAT) were administered. There was a statistically significant effect of abilities on DMC likelihood. DMC was judged more likely when cognitive abilities were demonstrated. There were no other significant effects. Age-bias, measured implicitly and explicitly, did not influence DMC likelihood. Contrary to the hypothesis, DMC likelihood was unaffected by client age. This suggests that training can mitigate age-bias in simulated clinical DMC evaluation.