Table 1.
Characteristics of participants in metformin and placebo groups at DPP baseline (1996–1999)
| Cohort for glucose-based diagnoses |
Cohort for HbA1c-based diagnoses |
|||||
|---|---|---|---|---|---|---|
| Total (N = 2,155) | Placebo (N = 1,082) | Metformin (N = 1,073) | Total (N = 1,833) | Placebo (N = 922) | Metformin (N = 911) | |
| Age (yr) | ||||||
| Mean ± SD | 50.6 ± 10.4 | 50.3 ± 10.4 | 50.9 ± 10.3 | 50.3 ± 10.3 | 50.1 ± 10.4 | 50.4 ± 10.2 |
| 25–44 | 642 (29.8) | 324 (29.9) | 318 (29.6) | 562 (30.7) | 283 (30.7) | 279 (30.6) |
| 45–59 | 1,098 (51.0) | 557 (51.5) | 541 (50.4) | 934 (51) | 468 (50.8) | 466 (51.2) |
| ≥60 | 415 (19.3) | 201 (18.6) | 214 (19.9) | 337 (18.4) | 171 (18.5) | 166 (18.2) |
| Female | 1,457 (67.6) | 747 (69.0) | 710 (66.2) | 1,249 (68.1) | 643 (69.7) | 606 (66.5) |
| Parous women | ||||||
| No history of GDM | 951 (80.3) | 487 (80.0) | 464 (80.6) | 818 (80.4) | 422 (80.2) | 396 (80.5) |
| History of GDM | 233 (19.7) | 122 (20.0) | 111 (19.3) | 200 (19.6) | 104 (19.8) | 96 (19.5) |
| Race/ethnicity | ||||||
| Non-Hispanic white | 1,188 (55.1) | 586 (54.2) | 602 (56.1) | 1,087 (59.3) | 539 (58.5) | 548 (60.2) |
| African American | 441 (20.4) | 220 (20.3) | 221 (20.6) | 287 (15.7) | 140 (15.2) | 147 (16.1) |
| Hispanic | 330 (15.3) | 168 (15.5) | 162 (15.1) | 290 (15.8) | 151 (16.4) | 139 (15.3) |
| American Indian | 111 (5.2) | 59 (5.5) | 52 (4.8) | 97 (5.3) | 50 (5.4) | 47 (5.2) |
| Asian/Pacific Islander | 85 (3.9) | 49 (4.5) | 36 (3.4) | 72 (3.9) | 42 (4.6) | 30 (3.3) |
| BMI (kg/m2) | ||||||
| Mean ± SD | 34.0 ± 6.6 | 34.1 ± 6.7 | 33.9 ± 6.6 | 33.7 ± 6.5 | 33.8 ± 6.5 | 33.6 ± 6.4 |
| <30 | 689 (32.0) | 340 (31.4) | 349 (32.5) | 603 (32.9) | 300 (32.5) | 303 (33.3) |
| 30 to <35 | 658 (30.5) | 315 (29.1) | 343 (32.0) | 574 (31.3) | 276 (29.9) | 298 (32.7) |
| ≥35 | 808 (37.5) | 427 (39.5) | 381 (35.5) | 656 (35.8) | 346 (37.5) | 310 (34) |
| Fasting glucose (mg/dL) | ||||||
| Mean ± SD | 106.6 ± 8.4 | 106.7 ± 8.4 | 106.5 ± 8.5 | 105.4 ± 7.4 | 105.6 ± 7.4 | 105.2 ± 7.4 |
| 95–109 | 1,440 (66.8) | 726 (67.1) | 714 (66.5) | 1,324 (72.2) | 663 (71.9) | 661 (72.6) |
| 110–125* | 715 (33.2) | 356 (32.9) | 359 (33.5) | 509 (27.8) | 259 (28.1) | 250 (27.4) |
| 2-h glucose (mg/dL) | ||||||
| Mean ± SD | 164.8 ± 17.2 | 164.5 ± 17.1 | 165.1 ± 17.2 | 164.0 ± 16.9 | 163.8 ± 16.9 | 164.3 ± 17.0 |
| 140–153 | 699 (32.8) | 360 (33.3) | 339 (31.6) | 617 (33.7) | 315 (34.2) | 302 (33.2) |
| 154–172 | 730 (34.3) | 374 (34.6) | 356 (33.2) | 633 (34.5) | 328 (35.6) | 305 (33.5) |
| 173–199 | 726 (33.7) | 348 (32.2) | 378 (35.2) | 583 (31.8) | 279 (30.3) | 304 (33.4) |
| HbA1c | ||||||
| Mean ± SD (%) | 5.9 ± 0.50 | 5.9 ± 0.51 | 5.9 ± 0.50 | 5.8 ± 0.39 | 5.8 ± 0.4 | 5.8 ± 0.4 |
| <6% (42 mmol/mol) | 1,168 (54.3) | 578 (53.6) | 590 (55.1) | 1,161 (63.3) | 576 (62.5) | 585 (64.2) |
| 6–6.4% (42–46 mmol/mL) | 982 (45.7) | 501 (46.4) | 533 (49.7) | 672 (36.7) | 346 (37.5) | 326 (35.8) |
Data are n (%) unless otherwise indicated. yr, years.
*Thirty-eight participants who were recruited prior to the American Diabetes Association change in diagnostic criteria (9) had fasting glucose levels between 125 and 139 mg/dL at baseline.