Inaccurate risk perceptions and individualized risk estimates by patients with type 2 diabetes.

Background: We evaluated how diabetic patients understand and respond to the presentation of personalized risk information.

Methods: This was a mixed methods study involving 56 patients with type 2 diabetes and at least 1 additional cardiovascular risk factor. We assessed participants' perceptions of diabetes-related risks; asked them to rank order 6 events (death, heart attack, stroke, blindness, amputation, and kidney failure) by likelihood of occurrence in a specified time frame; presented them with personalized risk estimates; and asked them to re-rank the risks. The final 18 participants were tested to verify understanding before re-ranking risks. Qualitative analysis of interview transcripts identified themes and concepts underlying participants' ways of perceiving and reacting to risk.

Results: While mortality was the most likely outcome for almost all participants, nearly all estimated it to be least likely; only 28% adjusted their mortality rankings to match model predictions. Some did not understand the risk information: only two thirds of those asked could rank risks according to the information presented. Risk perceptions were influenced by factors including "knowing myself," powerful anecdotes, and belief that a "warning shot" would occur before death.

Conclusions: Personalized risk estimates, particularly about mortality, had limited salience. Some participants could not understand the information, despite presentation in ways suggested by previous research.