A total of 320 adult subjects were approached to participate, of whom 65 declined participation. Only 1 subject declined because of the iPad. In addition, the first 55 subjects were excluded because of a misunderstanding of 2 of the verbatim questions. These items were reworded, and analysis therefore includes data from the subsequent 200 subjects who consented.
describes the demographics of each format group. As shown, there were no differences between groups. compares overall understanding (gist and verbatim) of the risk/benefit statistics among groups by literacy, numeracy, NFC, and education. Of note, bar graphs were the only format that showed significant differences in understanding between individuals with high and low numeracy, literacy, education, and NFC. There also were no differences in understanding by age (<65 vs ≥65 years) and between subjects who were currently taking statins compared with those who were not. Subjects had no difficulties using the program.
Subjects’ Understanding of Risks and Benefits by Message Format
When shown all 4 formats, 64 subjects (32.0%) stated that they preferred pictographs, 62 subjects (31.0%) stated that they preferred bar graphs, 39 subjects (19.5%) stated that they preferred pie charts, and 35 subjects (17.5%) stated that they preferred text. Of those who received text information, only 5 (10%) stated that they actually preferred text. Only 3 subjects (6%) who received the pie chart actually preferred the pie chart, 8 subjects (16%) who were assigned to the bar graph preferred the bar graph, and 12 subjects (24%) who were assigned to the pictograph preferred the pictograph. Overall, graphs were preferred to text (82.5% vs 17.5%, P < .001). This difference was consistent among subjects with both low and high numeracy, education, age, and NFC. Men were significantly more likely to prefer graphs than were women (89.1% vs 76.4%, P = .019). Of note, despite a stated preference for graphs, text was deemed more “effective” in presenting risk/benefit statistics (8.5 ± 1.5 vs 7.75 ± 2.2 of 10, P = .007), “clearer” to understand (8.82 ± 1.5 vs 8.1 ± 1.9, P = .004), and more “scientific” (7.82 ± 1.8 vs 6.7 ± 2.5, P = .001).
Significantly more subjects stated they would prefer to receive medical information on a computer or tablet device (52.0%) compared with conventional print media (39.4%, P = .012). Furthermore, 174 subjects (87.0%) also stated that they liked to receive supplemental verbal information about risks and benefits. Indeed, the accompanying narrative was deemed “helpful,” scoring 7.72 ± 2.3 of 10 (10 = extremely helpful). Older subjects (≥52 years, based on median split) found the narrative to be significantly more “helpful” than younger subjects (8.16 ± 1.9 vs 7.17 ± 2.6 of 10, P = .003). Likewise, minority subjects found the narrative more “helpful” than white subjects (8.85 ± 1.5 vs 7.61 ± 2.3, P = .003).
Of note, subjects whose preferred message format matched their randomly assigned format (preference match) had significantly greater understanding and satisfaction compared with those who were assigned to something other than their preference (). Of those with a preference match, 42.9% matched with pictographs, 28.6% matched with bar graphs, 17.9% matched with text, and 10.7% matched with pie charts. Factors found to be significantly associated with understanding by univariate analysis were entered into a regression model, that is, age, literacy, numeracy, education (high school vs college), family income, and preference match. Results identified several independent predictors of understanding, including higher numeracy, higher literacy, college education, and preference match ().
Relationship Between Preference Match* and Subjects’ Understanding, Satisfaction, and Perceptions
Independent Predictors of Understanding