The Best Predictor of Future Behavior May Be the Past: Exploring Behavior Change in Men Who Have Sex with Men Using Pre-exposure Prophylaxis in the Netherlands

Abstract

Pre-exposure prophylaxis (PrEP) use prevents HIV transmission, and may lead to changes in sexual behavior. We aimed to explore sexual behavior over time, and identify predictors of behavior change in men who have sex with men (MSM) using PrEP at sexual health centers (SHC) in the Netherlands. We used longitudinal data from the national STI surveillance database (January 2018-June 2021) of HIV-negative MSM who first initiated PrEP in the national PrEP pilot. We modelled behavior change after PrEP initiation, and identified predictors of behavior change using multi-state Markov models. The probability of stopping group sex, chemsex, use of poppers or erection stimulants, and having ≥ 10 partners in the past 6 months among included MSM (n = 4,349, n SHC visits = 21,820) was higher compared to the probability of starting with these behaviors after PrEP initiation. However, MSM who used condoms consistently during anal sex had a high probability of changing to inconsistent condom use (0.8) at the next visit, and inconsistent condom users mostly remained inconsistent (0.8). First visit, visiting the SHC more often (vs. regular), and STI diagnosis were predictors of starting or continuing with most of the behaviors associated with increased risk. Behavior change was less likely among older participants (> 34 compared to ≤ 34 years), and during COVID-19 lockdown and post-lockdown periods compared to pre-COVID-19. Although condom use decreased over time, transitions towards stopping with other behaviors associated with increased likelihood of acquiring an STI after PrEP initiation were common. This may suggest increased sexual empowerment, especially among younger MSM. Predictors of behavior change may help to identify MSM who are likely to start with or continue to engage in these behaviors in the near future and to provide suitable and timely counselling about behavior and PrEP adherence.

Keywords: Men who have sex with men; Pre-exposure prophylaxis; Sexual behavior; Sexual orientation; Sexually transmitted infections.

Fig. 1

Flowchart of clients included in the study who initiated PrEP use in the national PrEP pilot and who had at least two consultations at an SHC between January 2018 and June 2021. Chemsex was defined as the use of (a combination of) crystal meth, mephedrone or gamma-hydroxybutyric acid/gamma-butyrolactone (GHB/GBL) before or during sex. GP = General Practitioner; HIV = Human Immunodeficiency Virus; MSM = Men Who Have Sex with Men; MSMW = Men Who Have Sex with Men and Women; PrEP = Pre-Exposure Prophylaxis

Fig. 2

Transition probabilities for moving from one category at the current visit to another at the next visit for group sex

Fig. 3

Transition probabilities for moving from one category at the current visit to another at the next visit for chemsex

Fig. 4

Transition probabilities for moving from one category at the current visit to another at the next visit for poppers and erection stimulants

Fig. 5

Transition probabilities for moving from one category at the current visit to another at the next visit for number of partners

Fig. 6

Transition probabilities for moving from one category at the current visit to another at the next visit for receptive anal sex. T1 = current visit; T2 = next visit; No = no insertive anal sex, Yes cons = Yes, consistent condom use, Yes incons = Yes, inconsistent condom use

Fig. 7

Transition probabilities for moving from one category at the current visit to another at the next visit for insertive anal sex T1 = current visit; T2 = next visit; No = no insertive anal sex, Yes cons = Yes, consistent condom use, Yes incons = Yes, inconsistent condom use