Table 1. Baseline and Follow-up Characteristics and AMD Severity Status by Treatment Arms for the Subgroup With Retinal Imaging (N = 1592).
| Characteristics | Risk factor characteristics by treatment group, No. (%) | P value | ||
|---|---|---|---|---|
| Lifestyle (n = 513) | Metformin (n = 546) | Placebo (n = 528) | ||
| Age, mean (SD), y | ||||
| At randomization | 49.2 (9.5) | 49.3 (8.8) | 48.6 (8.8) | .28 |
| At AMD | 69.2 (9.4) | 69.2 (8.8) | 68.6 (8.8) | .42 |
| Sex | ||||
| Female | 144 (28) | 170 (31) | 148 (28) | .44 |
| Male | 369 (72) | 376 (69) | 380 (72) | |
| Race and ethnicity | ||||
| African American | 104 (20) | 123 (22) | 106 (20) | .45 |
| American Indian | 41 (8) | 40 (7) | 45 (9) | |
| Asian | 34 (7) | 19 (4) | 28 (5) | |
| Hispanic | 91 (18) | 88 (16) | 85 (16) | |
| Non-Hispanic White | 243 (47) | 276 (51) | 264 (50) | |
| Smoking status at baseline | ||||
| Never | 317 (62) | 349 (64) | 326 (62) | .34 |
| Current | 24 (5) | 27 (5) | 38 (7) | |
| Ever | 172 (34) | 170 (31) | 164 (31) | |
| Baseline BMI, mean (SD) | 33.5 (6.0) | 33.3 (6.2) | 34.1 (6.6) | .16 |
| Type 2 diabetes status at AMD assessment | ||||
| No | 228 (45) | 245 (45) | 196 (37) | .02a |
| Yes | 285 (55) | 301 (55) | 332 (73) | |
| Years with any metformin, median (IQR) | 0 (0-7) | 18.5 (9.5-20.25) | 1.5 (0-8.5) | <.001a |
| AMD status | ||||
| Absent | 361 (70) | 381 (70) | 366 (69) | .09 |
| Early | 87 (17) | 78 (14) | 64 (12) | |
| Intermediate | 56 (11) | 78 (14) | 84 (16) | |
| Advanced | 9 (2) | 9 (2) | 14 (3) | |
Abbreviations: AMD, age-related macular degeneration; BMI, body mass index (calculated as weight in kilograms divided by height in meters squared).
a
Significant association using P < .05 threshold.