Baseline characteristics, by STI diagnosis (N=451)
| Neisseria gonorrhoeae (n=35) | Chlamydia trachomatis (n=136) | Trichomonas vaginalis (n=28) | Any STI at baseline (n=174) | No STI at baseline (n=277) | P value | |
| Site | 0.0001 | |||||
| Cape Town, South Africa | 21 (60%) | 56 (41%) | 7 (25%) | 72 (41%) | 69 (25%) | |
| Johannesburg, South Africa | 6 (17%) | 50 (37%) | 10 (36%) | 62 (36%) | 100 (36%) | |
| Harare, Zimbabwe | 8 (23%) | 30 (22%) | 11 (39%) | 40 (23%) | 108 (39%) | |
| Age (years) | 0.036 | |||||
| Median (IQR) | 20 (18–21) | 20 (19–22) | 21 (20–24) | 20 (19–22) | 21 (19–23) | |
| Lives with | 0.080 | |||||
| Partner | 5 (14%) | 24 (18%) | 8 (29%) | 31 (18%) | 67 (24%) | |
| Parents and/or siblings | 24 (69%) | 75 (55%) | 14 (50%) | 98 (56%) | 160 (58%) | |
| Others | 6 (17%) | 37 (27%) | 6 (21%) | 45 (26%) | 50 (18%) | |
| Partner age difference | 0.154 | |||||
| Less than 5 years | 29 (83%) | 97 (71%) | 19 (68%) | 125 (72%) | 177 (64%) | |
| ≥5 and <10 years | 6 (17%) | 31 (23%) | 7 (25%) | 40 (23%) | 75 (27%) | |
| ≥10 years | 0 (0%) | 8 (6%) | 2 (7%) | 9 (5%) | 25 (9%) | |
| Partner has made you feel unsafe, afraid or in danger in past year | 9 (26%) | 20 (15%) | 3 (11%) | 27 (16%) | 63 (23%) | 0.069 |
| CES-D score ≥10* | 21 (60%) | 79 (58%) | 16 (57%) | 102 (59%) | 166 (60%) | 0.765 |
| Contraceptive method | 0.045 | |||||
| Injectable contraceptives | 23 (66%) | 68 (50%) | 7 (25%) | 87 (50%) | 104 (38%) | |
| Implants | 5 (14%) | 25 (18%) | 10 (36%) | 35 (20%) | 69 (25%) | |
| IUD-copper/hormone | 0 (0%) | 0 (0%) | 0 (0%) | 0 (0%) | 4 (1%) | |
| Sterilisation | 0 (0%) | 0 (0%) | 1 (4%) | 1 (1%) | 0 (0%) | |
| Oral contraceptives | 1 (3%) | 18 (13%) | 6 (21%) | 20 (11%) | 34 (12%) | |
| Condoms, natural methods or none | 6 (17%) | 25 (19%) | 4 (15%) | 31 (18%) | 66 (24%) | |
| Transactional sex, past month | 7 (20%) | 28 (21%) | 12 (43%) | 42 (24%) | 59 (21%) | 0.489 |
| Anal sex, past month | ||||||
| Yes | 7 (20%) | 21 (15%) | 2/28 (7%) | 27 (16%) | 41 (15%) | 0.391 |
| No | 20 (57%) | 78 (57%) | 17 (61%) | 101 (58%) | 146 (53%) | |
| Prefer not to answer | 8 (23%) | 37 (27%) | 9 (32%) | 46 (26%) | 90 (32%) | |
| No of vaginal sex episodes, past month | 0.307 | |||||
| Median (IQR) | 5 (2–10) | 4 (2–6) | 6 (4–12) | 4 (2–8) | 4 (3–8) | |
| Condom use at last vaginal sex† | 8 (29%) | 33 (31%) | 7 (29%) | 44 (31%) | 96 (45%) | 0.033 |
| Coinfection with other STIs | ||||||
| C. trachomatis | 19 (54%) | 136 (100%) | 7 (25%) | 136 (78%) | 0 (0%) | |
| N. gonorrhoeae | 35 (100%) | 19 (14%) | 1 (4%) | 35 (20%) | 0 (0%) | |
| T. vaginalis | 1 (3%) | 7 (5%) | 28 (100%) | 28 (16%) | 0 (0%) | |
| High self-perceived HIV risk in next year‡ | 1 (3%) | 10 (7%) | 3 (11%) | 12 (7%) | 22 (8%) | 0.430 |
| Modified VOICE risk score§ | 0.544 | |||||
| Median (IQR) | 7 (6–8) | 7 (5–7) | 6 (5–7) | 7 (6–7) | 7 (5–7) | |
| PrEP accepted at baseline | 33 (94%) | 120 (88%) | 27 (96%) | 157 (90%) | 255 (92%) | 0.500 |
*Missing values imputed, n=9 missing responses.
†Missing responses n=33 for those with STI and n=66 for those with no STI.
‡Missing responses n=2 for those with no STI.
§Modified risk score does not include score for curable STI at baseline; includes age <25 years=2, ≥25 years=0; married or living with primary partner no=2, yes =0; partner provides material support no=1, yes =0; primary partner has other partners yes=2, don’t know=2, no=0.
CES-D, Center for Epidemiological Studies Depression; IUD, intrauterine device; PrEP, pre-exposure prophylaxis; STI, sexually transmitted infection.