Assessment of Demographic and Socio-Behavioral Factors on Adherence to HIV Pre-Exposure Prophylaxis Using a Markov Modeling Approach

Abstract

Purpose: Adherence is important for the effectiveness of human immunodeficiency virus (HIV) preexposure prophylaxis (PrEP). The objective of the current work is to assess the impact of multiple demographic and socio-behavioral factors on the adherence to tenofovir-based PrEP among HIV serodiscordant couples in East Africa using Markov mixed-effects modeling approach. Methods: The Partners Demonstration Project was a prospective, open-label, implementation science-driven study of HIV PrEP among heterosexual HIV serodiscordant couples in Kenya and Uganda. The uninfected partner received oral PrEP according to the “bridge to antiretroviral therapy [ART]” strategy (i.e., until the infected partner had been on ART for ≥6 months). Adherence was monitored electronically; demographic and socio-behavioral data were collected during study visits. Analyzed data reflect 12 months of follow-up per participant. A two-state, first-order, discrete time Markov model was developed with longitudinal adherence data characterized by “dose taking (1)” and “dose missing (0).” Covariate effects were linearly added in the logit domain of transition probability parameters (P01 and P10) in the model. The full covariate model was initially developed, followed by backward elimination process to reduce the model. All significant covariates reported by a prior primary statistical analysis of the same data were included in the full covariate model. Results: The model included data from 920 participants, who were predominantly male (65%). Significant covariates associated with higher adherence were 25 years or older [odds ratio (OR) for P10, 0.61], female sex (OR for P10, 0.67), participant wanting the relationship with the partner to succeed (OR for P10, 0.79; OR for P01, 1.45), and sex with partner either with 100% or <100% condom use compared to those reported no sex (OR for P10, 0.84; OR for P01, 1.21). Significant covariates associated with lower adherence were partner on ART >6 months (OR for P01, 0.86; OR for P10, 1.34), subject in the study for >6 months (OR for P01, 0.8; OR for P10, 1.25), and problematic alcohol use (OR for P01, 0.63; OR for P10, 1.16). Conclusion: The developed Markov model provides a mechanistic understanding of relationship between demographic, socio-behavioral covariates, and PrEP adherence, by indicating the pattern of adherence influenced by each factor over time. Such data can be used for further intervention development to promote PrEP adherence.

PrEP Use Awareness and Interest Cascade among MSM and Transgender Women Living in Bali, Indonesia

“…Consisting of some of the same active regiments used in antiretroviral (ARV) therapy (ART), HIV pre-exposure prophylaxis (PrEP) has been shown to protect against HIV infection in MSM and TGW [ 6 , 7 ], provided that users are adherent [ 8 , 9 , 10 , 11 , 12 ]. Individuals need to take PrEP during periods of high risk of exposure to HIV, a concept that has been termed “prevention-effective adherence” [ 12 ].…”

Infectious Disease Modelling of HIV Prevention Interventions: A Systematic Review and Narrative Synthesis of Compartmental Models

“…Instead, a standard reduction of efficacy was applied to all groups receiving the intervention or alternatively adherence differences were enveloped into the differing rates of infections by risk group level. Stratification by subgroup should be considered as adherence is impacted by many factors including age [ 87 – 90 ], ethnicity [ 90 ], and sex/gender [ 88 , 89 ].…”

Perceived influence of alcohol consumption, substance use, and mental health on PrEP adherence and condom use among PrEP-prescribed gay, bisexual, and other men-who-have-sex-with-men: a qualitative investigation

“…On the one hand, evidence from some quantitative and qualitative investigations has provided support for associations between lower PrEP adherence and alcohol consumption [29][30][31][32][33][34], substance use [33][34][35][36][37][38][39][40][41], and depression [40][41][42][43]; suggesting that these factors may hinder one's motivation and/or ability to take PrEP as prescribed. In contrast, findings from other studies have demonstrated that some GBMSM are able to successfully adhere to their PrEP regimens, even when experiencing addictions-and mental health-related concerns [36-39, 44, 45].…”