1. Prevalence, Trends, and Correlates of HIV Pre-Exposure Prophylaxis (PrEP) Use During Sexual Events by Sexual Minority Men in Montreal, Toronto, and Vancouver
Lachowsky NJ1, Cui Z2, Bacani N2, Armstrong HL2,3, Olarewaju G2, Messier-Peet M4, Apelian H4, Rodrigues R5, Noor S5, Skakoon-Sparling S5, Moore DM2,3, Jollimore J6, Lambert G4, Cox J7, Grace D8, Hart TA5,8, and the Engage team
1. University of Victoria; 2. BC Centre for Excellence in HIV/AIDS; 3. University of British Columbia; 4. Direction Régionale de Santé Publique de Montréal; 5. Ryerson University; 6. Community Based Research Centre Society; 7. McGill University; 8. University of Toronto

2. Conflict of Interest Disclosures
In the past 2 years I have been an employee of: University of Victoria
In the past 2 years I have been a consultant for: None
In the past 2 years I have held investments in the following pharmaceutical organizations, medical devices companies or communications firms: None
In the past 2 years I have been a member of the Scientific advisory board for: None
In the past 2 years I have been a speaker for: None
In the past 2 years I have received research support (grants) from: Canadian Blood Services, Canadian Foundation for AIDS Research, CIHR, CIHR HIV Clinical Trials Network, Gilead Science Canada, Island Health, Mitacs, Michael Smith Foundation for Health Research, Public Health Agency of Canada, University of Victoria, Vancouver Foundation
In the past 2 years I have received honoraria from: Saskatchewan Health Research Foundation, Michael Smith Foundation for Health Research
I agree to disclose approved and non-approved indications for medications in this presentation: YES
I agree to use generic names of medications in this presentation: YES
There are relationships to disclose: YES (see above)

3. Background
Since Health Canada approval in 2016,1 PrEP awareness and use has increased markedly2
PrEP access varies across Canada:
Indigenous people with status: free access via non-insured health benefits
British Columbia: free access via BC-CfE within provincial clinical guidelines
Ontario: free if <25, over 65, or ODSP/Ontario Works
income-contingent access to coverage via provincial drug plan (Trillium)
Quebec : co-pay via provincial health plan (RAMQ) up to $83.33/month
Private health insurance plans
Tan et al. CMAJ 2017
Mosley et al. AIDS Behav 2018

4. Background (continued)
Sexual event-level analyses can provide granular evidence of the impact of HIV PrEP-use on the sexual behaviour of gay, bisexual, and other men who have sex with men (gbMSM).3
“One with many” design
We examined the prevalence, trends and correlates of sexual event-level HIV PrEP-use among urban gbMSM
Cite good for first point here too
3. Lachowsky et al. (2016) STDs

5. What is Engage? Mixed-method biobehavioural cohort study
Initiated in 2014 in Toronto, Montreal, and Vancouver
Focused on the health of gbMSM (inclusive of trans men):
Eligible if sexually active (past six months) and aged ≥16 years
Computer-assisted surveys & biomedical testing
Uses respondent-driven sampling (RDS)
Social network-based chain recruitment

6. Methods
“Partner Matrix” asks questions on their last sexual encounter with up to their five most recent partners in the last 6 months
Outcome: Participant and/or partner PrEP use
Data from all visits between Feb 2017 – Feb 2019 (2 years)
RDS-II weights applied to all analyses
Multivariable logistics regression to evaluate temporal trends (6-monthly) and factors associated with event-level PrEP use
General estimating equations accounted for individual as main clustering level using an exchange correlation structure
City and visit number were controlled for in the models
CODE
proc genmod data = sex_prep_mdl;
class PART_ID SEX_EL_PREP_USE city &vars/param=ref ref=first;
model SEX_EL_PREP_USE = visit_num city &vars/dist=binomial link=logit type3;
repeated subject = PART_ID/type = exch;
weight wt;
run;

7. Results: Study Sample 2198 participants 3486 study visits
11474 sexual events
3277 events with PrEP use (28.6%)
Sample size by city (% of overall):
Montreal: n=1179 (53.6%)
Toronto: n=422 (19.2%)
Vancouver: n=597 (27.2%)
Descriptive statistics:
90.4% cisgender
75.6% gay-identified
63.9% Canadian/European-identified
63.9% earned <$30,000/year
43.2% aged <30 years
44.1% have a current romantic partner
23.7% completed high school or less education
15.6% identified as living with HIV
9.2% reported recent PrEP use (individual-level)
Average of 3.3 events per visit
40 visits did not have any sexual events
1201 events had a missing outcome

8. Event-Level PrEP Use: Trends by HIV Status
HIV- trend P<0.001
Difference by HIV Status: P=0.2143
Overall trend P<0.001
PLHIV trend P=0.318

9. Event-Level PrEP Use: Trends by City
trend P<0.001
trend P<0.001
Difference by City: P=0.0422
trend P=0.062

10. Event-Level PrEP Use: Multivariable Correlates
AOR
95% CI
Relationship With Partner (ref: current romantic partner)
Transactional sex (money, goods, or drugs)
2.82
( )
One-time hookup
3.39
( )
Other (e.g. friends, casual)
3.22
( )
Recent Place (ref: my/their home)
Bathhouse
0.66
( )
Sexual Activity (separate variables)
Received oral sex (ref: did not)
0.79
( )
Condom used as bottom (ref: did not)
0.60
( )
Condom used as top (ref: did not)
0.40
( )
Gave rim job (ref: did not)
1.22
( )
Participant Substance Use (separate variables)
Alcohol, 5+ drinks (ref: not used)
0.67
( )
Crystal methamphetamine (ref: not used)
0.65
( )
Poppers (ref: not used)
1.71
( )
Model controls for:
City
Age
Income
Ethnicity
Sexual identity
Education
Relationship status
HIV status

11. Discussion Event-level PrEP-use increased over time and varied by city
Vancouver’s marked increase a result of provincial PrEP coverage?
Contextual factors should inform future health promotion
PrEP-reported events more common with non-romantic partners, notably during transactional sex
PrEP-reported events less likely to involve substances associated with condom non-use (e.g. binge drinking, crystal meth)
Less PrEP-reported events at bathhouses due to non-verbal conversations?

12. Strengths & Limitations
Novel approach to use sexual events as analytic unit
Greater causal evidence (temporal association)
Distribution of study visits vary by city
Limited follow-up visits
Outcome was self-reported PrEP use for participant or partner
Either or both could have reported PrEP use
Self-reported by participant (future research should explore dyadic data)
How accurate are self-reports of PrEP use?

13. Conclusions
PrEP use is reported in one third to half of all sexual events in Canada’s largest urban centres
Access to PrEP is an important individual and community issue
Need to consider equity in PrEP implementation
Key factors include both social determinants and contextual partner- level and event-level
Future research can examine issue with more granularity
PrEP use by participant and by partner
Addition or substitution of other prevention practices
e.g. condoms + lube, strategic positioning

14. Community & Public Health Partners
Acknowledgements
Community & Public Health Partners

15. Acknowledgements
Academic Partners

16. Acknowledgements
Funders