Table 1.
Baseline Characteristics of the Subjects.*
| Characteristic | FTC–TDF (N = 1251) | Placebo (N = 1248) | P Value |
|---|---|---|---|
| Age group — no. (%) | 0.04 | ||
| 18–24 yr | 591 (47) | 662 (53) | |
| 25–29 yr | 274 (22) | 241 (19) | |
| 30–39 yr | 249 (20) | 224 (18) | |
| ≥40 yr | 137 (11) | 121 (10) | |
| Education level — no. (%) | 0.26 | ||
| Less than secondary | 279 (22) | 244 (20) | |
| Completed secondary | 430 (34) | 453 (36) | |
| Postsecondary | 525 (42) | 539 (43) | |
| No answer or missing data | 17 (1) | 12 (1) | |
| Race or ethnic group — no. (%)† | 0.40 | ||
| Black | 117 (9) | 97 (8) | |
| White | 223 (18) | 208 (17) | |
| Mixed race or other | 849 (68) | 878 (70) | |
| Asian | 62 (5) | 65 (5) | |
| Hispanic | 900 (72) | 906 (73) | 0.72 |
| No. of alcoholic drinks (on days when subject drank in past month) — no. (%) | 0.66 | ||
| 0 | 206 (16) | 184 (15) | |
| 1–4 per day | 348 (28) | 345 (28) | |
| ≥5 per day | 666 (53) | 687 (55) | |
| No answer or missing data | 31 (2) | 32 (3) | |
| City and country of residence — no. (%) | 1.00 | ||
| Lima, Peru | 470 (38) | 470 (38) | |
| Iquitos, Peru | 230 (18) | 230 (18) | |
| Guayaquil, Ecuador | 150 (12) | 150 (12) | |
| Rio de Janeiro | 147 (12) | 147 (12) | |
| São Paulo | 39 (3) | 37 (3) | |
| San Francisco | 70 (6) | 70 (6) | |
| Boston | 43 (3) | 44 (4) | |
| Chiang Mai, Thailand | 57 (5) | 57 (5) | |
| Cape Town, South Africa | 45 (4) | 43 (3) | |
| Sexual risk factors at screening | |||
| No. of partners in past 12 wk | 18±35 | 18±43 | 0.51 |
| Unprotected receptive anal intercourse in past 12 wk — no. (%) | 732 (59) | 753 (60) | 0.37 |
| Unprotected anal intercourse with partner with positive or unknown HIV status in past 6 mo — no. (%) | 992 (79) | 1009 (81) | 0.34 |
| Transactional sex in past 6 mo — no. (%) | 517 (41) | 510 (41) | 0.84 |
| Known partner with HIV in past 6 mo — no. (%) | 23 (2) | 32 (3) | 0.22 |
| Sexually transmitted infections diagnosed at screening | |||
| Syphilis seroreactivity — no./total no. (%) | 164/1240 (13) | 162/1239 (13) | 0.95 |
| Serum herpes simplex virus type 2 — no./total no. (%) | 458/1241 (37) | 430/1243 (35) | 0.24 |
| Urine leukocyte esterase positive — no. (%) | 23 (2) | 22 (2) | 1.00 |
| Hepatitis B virus status — no. (%) | 0.11 | ||
| Susceptible | 827 (66) | 803 (64) | |
| Immune because of natural infection | 247 (20) | 222 (18) | |
| Immune because of previous vaccination | 149 (12) | 190 (15) | |
| Current infection with hepatitis B virus | 7 (1) | 6 (<1) | |
| Indeterminate | 21 (2) | 27 (2) |
*
Plus–minus values are means ±SD. Percentages may not total 100 because of rounding. FTC–TDF denotes emtricitabine and tenofovir disoproxil fumarate.
†
Race or ethnic group was self-reported.