Risk Ladder, Table, or Bulleted List? Identifying Formats That Effectively Communicate Personalized Risk and Risk Reduction Information for Multiple Diseases.

Background: Personalized medicine may increase the amount of probabilistic information patients encounter. Little guidance exists about communicating risk for multiple diseases simultaneously or about communicating how changes in risk factors affect risk (hereafter "risk reduction").
Purpose: To determine how to communicate personalized risk and risk reduction information for up to 5 diseases associated with insufficient physical activity in a way laypeople can understand and that increases intentions.
Methods: We recruited 500 participants with <150 min weekly of physical activity from community settings. Participants completed risk assessments for diabetes, heart disease, stroke, colon cancer, and breast cancer (women only) on a smartphone. Then, they were randomly assigned to view personalized risk and risk reduction information organized as a bulleted list, a simplified table, or a specialized vertical bar graph ("risk ladder"). Last, they completed a questionnaire assessing outcomes. Personalized risk and risk reduction information was presented as categories (e.g., "very low"). Our analytic sample ( N = 372) included 41.3% individuals from underrepresented racial/ethnic backgrounds, 15.9% with vocational-technical training or less, 84.7% women, 43.8% aged 50 to 64 y, and 71.8% who were overweight/obese.
Results: Analyses of covariance with post hoc comparisons showed that the risk ladder elicited higher gist comprehension than the bulleted list ( P = 0.01). There were no significant main effects on verbatim comprehension or physical activity intentions and no moderation by sex, race/ethnicity, education, numeracy, or graph literacy ( P > 0.05). Sequential mediation analyses revealed a small beneficial indirect effect of risk ladder versus list on intentions through gist comprehension and then through perceived risk ( b _{IndirectEffect} = 0.02, 95% confidence interval: 0.00, 0.04).
Conclusion: Risk ladders can communicate the gist meaning of multiple pieces of risk information to individuals from many sociodemographic backgrounds and with varying levels of facility with numbers and graphs.