Dissertation
Elevated bacterial STI incidence in Canada: reframing clinical decision making for HIV prep beyond risk compensation
Doctor of Philosophy (Ph.D.), Drexel University
Sep 2022
DOI:
https://doi.org/10.17918/00001351
Abstract
Rates of sexually transmitted infections (STI) have increased among gay, bisexual, and men who have sex with other men (GBM) in Canada, particularly gonorrhea and syphilis. If left untreated, these bacterial STI can cause serious sequalae among GBM such infertility and prostatitis as well as increase the risk of HIV transmission. Based on the theory of risk compensation, pre-exposure prophylaxis (PrEP) has been hypothesized as the primary contributing factor to the recent growth in bacterial STI incidence. However, findings are conflicting due to the methodological challenges of assessing how PrEP use facilitate behavioral changes for other prevention strategies such as condom use, subsequently increasing bacterial STI risk. Thus, this dissertation examined whether a) time-varying PrEP uptake affected cumulative bacterial STI incidence, b) condomless anal sex mediated the relation between PrEP uptake and bacterial STI, and c) characteristics of sexual partnerships were associated with elevated bacterial STI incidence among GBM in the era of PrEP. To answer address these research aims, this dissertation used data from the iCruise study, an online longitudinal study of GBM in Ontario, Canada. I used methods in causal inference to construct marginal structural models to evaluate the effect of PrEP uptake on rates of bacterial STI incidence and mediation models to quantify the indirect effect through condomless anal sex. In the final aim, I broaden the scope of possible mechanisms contributing to increased STI risk and adopt a descriptive epidemiology approach to generate hypotheses regarding the potential impact of partnership characteristics on STI incidence. Overall, this dissertation did not find sufficient evidence of risk compensation among iCruise participants. It demonstrates that a different mechanism (or a set of mechanisms) may better explain the observed increases in STI incidence among GBM and those on PrEP.
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Details
- Title
- Elevated bacterial STI incidence in Canada
- Creators
- Nguyen Khai Tran
- Contributors
- Seth Welles (Advisor)Neal D. Goldstein (Advisor)
- Awarding Institution
- Drexel University
- Degree Awarded
- Doctor of Philosophy (Ph.D.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- xv, 114 pages
- Resource Type
- Dissertation
- Language
- English
- Academic Unit
- Dana and David Dornsife School of Public Health; Epidemiology and Biostatistics; Drexel University
- Other Identifier
- 991019104610904721