Table 1.
Overall comparison of medication adherence by demographic factors
| Metformin
|
Placebo
|
|||
|---|---|---|---|---|
| Demographic characteristics | n | Percent adherent | n | Percent adherent |
| Age (years) | ||||
| 25–44 | 293 | 65.9 | 302 | 70.1 |
| 45–59 | 519 | 72.5 | 530 | 77.3 |
| ≥60 | 208 | 70.6 | 192 | 81.0 |
| P value | 0.01 | 0.0001 | ||
| Sex | ||||
| Male | 348 | 73.7 | 316 | 78.4 |
| Female | 672 | 68.4 | 708 | 74.9 |
| P value | 0.01 | 0.07 | ||
| Ethnicity/race | ||||
| Caucasian | 577 | 73.4 | 550 | 80.7 |
| African American | 209 | 66.4 | 211 | 67.0 |
| Hispanic | 150 | 65.0 | 158 | 73.0 |
| American Indian | 52 | 67.5 | 59 | 72.1 |
| Asian | 32 | 68.5 | 46 | 75.3 |
| P value | 0.008 | <0.0001 | ||
| Income* | ||||
| <$20,000 | 126 | 60.1 | 146 | 76.8 |
| $20,000 to <$35,000 | 165 | 66.1 | 181 | 75.6 |
| $35,000 to <$50,000 | 203 | 74.7 | 206 | 74.6 |
| $50,000 to <$75,000 | 212 | 70.0 | 201 | 78.6 |
| ≥$75,000 | 231 | 77.2 | 210 | 78.6 |
| Refused | 82 | 64.7 | 80 | 65.1 |
| P value | <0.0001 | 0.01 | ||
| Marital status | ||||
| Never married | 126 | 67.4 | 127 | 77.8 |
| Living together | 29 | 62.4 | 44 | 75.7 |
| Married | 632 | 72.5 | 636 | 75.5 |
| Separated | 31 | 64.6 | 27 | 68.9 |
| Divorced | 152 | 67.3 | 145 | 77.2 |
| Widowed | 50 | 65.8 | 45 | 77.3 |
| P value | 0.09 | 0.72 | ||
| Education (years) | ||||
| ≤12 | 258 | 68.8 | 270 | 76.2 |
| 13–16 | 484 | 69.6 | 497 | 75.1 |
| ≥17 | 278 | 72.6 | 257 | 77.2 |
| P value | 0.33 | 0.66 | ||
*
The adherence difference between metformin and placebo is consistent across age, sex, ethnicity, marital status, and education. However, heterogeneity is observed for income levels (P = 0.01). Those with <$20,000 income had the biggest gap in adherence between metformin and placebo.