Table 3.
Sensitivity analyses: the associations between of PrEP initiation and HIV risk-related sexual behaviors within heterosexual serodiscordant couples
| Mean number of sex acts with study partner, past month | Any condomless sexa with study partner, past month | Any sex with non-study partner, past month | ||||
|---|---|---|---|---|---|---|
| MD (95% CI) | p | PP (95% CI) | p | PP (95% CI) | p | |
| 1. Censor participants when the study partner living with HIV has been on ART for 6 mos, n = 941 | ||||||
| PrEP initiation | − 1.10 (− 1.46 to − 0.75) | < 0.001 | − 32% (− 35% to − 29%) | < 0.001 | − 1% (− 3% to 0%) | 0.04 |
| Time since PrEP initiation | ||||||
| 1-month | − 1.20 (− 1.65 to − 0.75) | < 0.001 | − 34% (− 38% to − 31%) | <0.001 | − 2% (− 3% to 0%) | 0.03 |
| 3-months | − 0.65 (− 1.11 to − 0.18) | 0.01 | − 29% (− 33% to − 25%) | < 0.001 | − 2% (− 4% to 0%) | 0.03 |
| 6-months | − 0.96 (−1.50 to − 0.42) | 0.001 | − 30% (− 35% to − 26%) | < 0.001 | − 2% (− 4% to 1%) | 0.14 |
| 12-months | − 1.66 (− 2.22 to − 1.10) | < 0.001 | − 31% (− 35% to − 26%) | < 0.001 | 1% (− 1% to 3%) | 0.55 |
| >12-months | − 1.87 (− 2.60 to − 1.15) | < 0.001 | − 35% (−41% to − 29%) | < 0.001 | − 1% (−3% to 2%) | 0.66 |
| 2. Censor participants not adhering to PrEPb, n = 940 | ||||||
| PrEP initiation | − 0.99 (− 1.38 to − 0.60) | < 0.001 | − 31% (− 34% to − 27%) | <0.001 | − 1% (− 2% to 0%) | 0.22 |
| Time since PrEP initiation | ||||||
| 1-month | − 1.17 (− 1.66 to − 0.68) | < 0.001 | − 35% (− 39% to − 31%) | < 0.001 | − 1% (− 3% to 1%) | 0.21 |
| 3-months | − 0.38 (− 0.91 to 0.15) | 0.16 | − 30% (− 34% to -25%) | < 0.001 | − 1% (− 3% to 0%) | 0.11 |
| 6-months | − 0.46 (− 1.02 to 0.11) | 0.11 | − 30% (− 35% to − 26%) | < 0.001 | − 1% (− 2% to 2%) | 0.60 |
| 12-months | − 1.12 (− 1.64 to − 0.60) | < 0.001 | − 26% (− 30% to − 21%) | < 0.001 | − 1% (− 2% to 1%) | 0.55 |
| >12-months | − 2.03 (− 2.63 to − 1.44) | < 0.001 | − 29% (− 34% to − 24%) | <0.001 | 0% (− 2% to 2%) | 0.97 |
| 3. Limit to participants who knew their partner was living with HIV > 3 mos prior enrollment, n = 231 | ||||||
| PrEP initiation | − 0.44 (− 0.96 to 0.08) | 0.10 | − 6% (− 11% to − 1%) | 0.02 | 0% (− 3% to 2%) | 0.94 |
| Time since PrEP initiation | ||||||
| 1-month | − 0.68 (− 1.38 to 0.03) | 0.06 | − 9% (− 16% to − 2%) | 0.008 | − 2% (− 5% to 1%) | 0.22 |
| 3-months | − 0.19 (− 0.90 to 0.53) | 0.61 | − 6% (− 13% to 1%) | 0.12 | − 3% (− 7% to 0%) | 0.05 |
| 6-months | 0.27 (− 0.44 to 0.99) | 0.45 | − 6% (− 13% to 1%) | 0.10 | − 2% (− 5% to 2%) | 0.30 |
| 12-months | − 0.21 (− 0.84 to 0.41) | 0.50 | − 6% (− 12% to 0%) | 0.05 | 1% (− 2% to 4%) | 0.58 |
| >12-months | − 0.78 (− 1.34 to − 0.21) | 0.01 | − 5% (− 11% to 0%) | 0.07 | 2% (− 1% to 5%) | 0.19 |
Associations measured using individual longitudinal data and linear regression models with fixed effects for individuals, fertility intentions (trying, not trying, pregnant), sex with a non-study partner (study partner outcomes only), treatment for a genital infection, use of hormonal contraception, calendar month, and number of sex acts (any condomless sex outcome only)
MD mean difference, CI confidence interval, P p-value, PP percentage point change
aParticipant reports having condomless sex with study partner at least once in the past month
bParticipants took > 80% of expected doses, measured using electronic medication even monitoring (MEMS) bottle caps