Table 4

Mean utility value of taking 1 pill/day by participant characteristics*

Characteristic	Standard gamble			Willingness-to-pay†,‡
Characteristic	n	Mean	p Value*	n	Mean	p Value*
Age (years)
18–35	211	0.9966	0.003	210	0.9989	0.017
36–50	206	0.9973		204	0.9992
>50	291	0.9963		176	0.9985
Sex
Female	590	0.9966	0.006	504	0.9989	0.119
Male	118	0.9974	0.006	86	0.9985	0.119
Race
African–American	80	0.9934	0.225	68	0.9992	0.010
Caucasian	565	0.9973		472	0.9989
Other	63	0.9957		50	0.9985
Education level
<College degree	104	0.9950	0.011	80	0.9993	0.012
College or graduate degree	604	0.9970	0.011	510	0.9988	0.012
Income level
<$25 000	43	0.9971	0.713	30	0.9963	0.164
$25 000–$75 000	323	0.9966		269	0.9989
>$75 000	342	0.9968		291	0.9991
Health rating
<Very good	278	0.9964	0.167	220	0.9987	0.314
≥Very good	430	0.9969	0.167	370	0.9989	0.314
Numeracy level§
Low	115	0.9919	0.059	91	0.9994	<0.001
Adequate	593	0.9976	0.059	499	0.9988	<0.001
Difficulty obtaining pills
Not difficult	594	0.9971	0.316	497	0.9989	0.147
Neutral	59	0.9962		49	0.9985
Difficult	55	0.9925		44	0.9990
Difficulty paying for pills
Not difficult	493	0.9976	0.682	418	0.9988	0.545
Neutral	101	0.9969		80	0.9991
Difficult	114	0.9925		92	0.9990
Number of times pills taken per day
<2	350	0.9961	0.263	297	0.9989	0.998
≥2	358	0.9973	0.263	293	0.9989	0.998
Number of pills taken per day
0	26	0.9953	0.107	25	0.9979	0.792
1	113	0.9965		98	0.9990
2	110	0.9989		93	0.9987
3+	459	0.9963		374	0.9989

Utilities derived using standard gamble technique or willingness-to-pay technique, as indicated.
*p Values based on Kruskal-Wallis test.
†Participants with missing age data (n=95) and age ≥65 (n=19) removed prior to calculating mean and p value (114 responses removed).
‡Outliers below 0.95 were removed from data prior to calculating mean and p value (4 responses removed).
§Numeracy level based on number of questions correct on numeracy question (0–1=low; 2–3=adequate).