Recent HIV Risk Behavior and Partnership Type Predict HIV Pre-Exposure Prophylaxis Adherence in Men Who Have Sex with Men.

Abstract

Men who have sex with men (MSM) reporting higher HIV risk behavior over time are often more adherent to pre-exposure prophylaxis (PrEP), but it is unclear if recent risk behavior and partnership type affect long-term PrEP adherence. HIV-negative MSM and transgender women completing the 48-week randomized study TAPIR (Daily Text Messages to Support Adherence to PrEP in At-Risk for HIV Individuals) were included. At baseline and weeks 24 and 48, a modified Calculated Risk (mCalcR) Score estimated the likelihood of HIV seroconversion over 1 year based on reported condomless anal sex acts in the last month and current sexually transmitted infection. mCalcR scores were categorized as low, moderate, and high/very high risk. Partnership type was classified as no partner/single HIV-negative partner (no/single-), single HIV-positive partner (single+), or multiple partners of any serostatus (multi) in the past 3 months. PrEP adherence was measured by intracellular tenofovir-diphosphate (TFV-DP) levels. Among 313 individuals, there was no difference in mCalcR category from baseline to week 48. There was a significant change in partnership type, with no/single partnerships increasing from 0.5% to 9%. Participants with moderate and high/very risk had higher TFV-DP levels than the low-risk group. No/single participants had lower TFV-DP levels than those reporting single+ or multi. Although there was a shift toward lower-risk partnerships, HIV risk category remained stable over time. Individuals with riskier behaviors and partnerships had higher PrEP drug levels, suggesting continued motivation for and adherence to PrEP.