Table 4.
PrEP adherence based on intracellular tenofovir diphosphate levels at month 3 or 6
| Description | Total | JOOTRH and KMET Kisumu | Tutu Teen Truck Cape Town a | Ward 21 Johannesburg a |
|---|---|---|---|---|
| N samples tested (% of eligible visits b ) | 193 (16.7%) | 65 (11.3%) | 32 (11.1%) | 96 (32.9%) |
| DBS TFV‐DP fmol/punch Median (IQR) | 510 (16–1263) | BLQ c (16–341) | 770 (56–1404) | 1063 (218–1394) |
| Estimated average weekly PrEP use d | ||||
| 7 doses/week (≥1450 fmol/punch) | 19.0% | 10.8% | 25.0% | 21.9% |
| 4–6 doses/week (800–1449 fmol/punch) | 28.2% | 9.2% | 25.0% | 41.7% |
| 2–3 doses/week (400–799 fmol/punch) | 5.1% | 4.6% | 3.1% | 6.3% |
| <2 doses/week (31.25–399 fmol/punch) | 19.5% | 23.1% | 28.1% | 14.6% |
| None (BLQ c , <31.25 fmol/punch) | 28.2% | 52.3% | 18.8% | 15.6% |
The three cities included two facilities each, two of which (Jeppestown clinic in Johannesburg and Weltevreden clinic in Cape Town) were excluded in this table because they had few or no specimens available for testing.
Eligible visits for TFV‐DP assessment were month 3 and/or 6 visits, where the participant had PrEP supply from the prior visit sufficient for daily dosing, from 11% of visits from participants with PrEP supply estimated to be sufficient for daily dosing were randomly selected from the two sites, which sent all DBS samples collected, and all from the third site, which sent a subset of 33% DBS samples collected.
Below limit of quantification (<31.25 fmol/punch).
Thresholds for intracellular tenofovir diphosphate levels in red blood cells associated with average doses per week in the 6 weeks prior to the DBS sample were based on directly observed dosing studies in studies of MSM, which measured TFV‐DP levels