Research

Areas of research

The OHTN Cohort Study research program focuses on four key areas of research

1. Social and Behavioral Research
2. Clinical Research
3. HIV Prevention Research
4. Health Services Research

The current scientific protocol and research policies can be found here.

Publications

Current Publication List.

Contact the OCS Study Coordinator at [email protected] if interested in a publication that is not available as a full text online.

OCS publication guidelines

Recent Conferences

Below are presentations and posters presented at recent conferences. These presentations were developed by study staff or external researchers in collaborative research teams. Click the title to access the poster or presentation slides.

You can access conference presentations and posters archive here.

2025 Canadian Conference on HIV/AIDS Research (CAHR)

Poster Presentations

• Bekele et al. Uptake of three doses of COVID-19 vaccine among people living with HIV who have completed a 2-dose primary series: Findings from the Ontario HIV Treatment Network (OHTN) Cohort Study.
  
  “Uptake of 3 doses of COVID-19 vaccine was significantly lower among women, heterosexual men, and people who identified as Black, used recreational drugs, and received care inEastern Ontario/ Southwestern Ontario. A targeted approach may help to improve uptake of updated COVID-19 vaccines in these groups”.

• Rehman et al. Association between virtual visits and health outcomes of people living with HIV: A cross-sectional study.
  
  “Virtual care has become a common way to access HIV services in Ontario, but its impact has not been well understood. This study found that people living with HIV who received virtual or blended care had good adherence to treatment, viral suppression, and mental health compared.”

• Rehman et al. Socio-economical determinants of use of virtual care in HIV care in a clinical cohort in Ontario, Canada: A cross-sectional study.
  
  “Virtual care was introduced to improve access to HIV services, but its use varies across different socio-demographic groups. This study found that people living outside Toronto, women, non-MSM individuals, those with lower education, and those recently diagnosed with HIV were less likely to use virtual care, highlighting the need to address equity in virtual healthcare access.”

• Su at al. Five-Year Trajectories of Disability and the Associated Factors Among Adults Aging with HIV in the Ontario HIV Treatment Network Cohort Study.
  
  “Disability experiences among adults living with HIV were episodic in nature and followed three distinct trajectories (low, medium, and high disability) over a 5-year period. These trajectories were influenced by a range of intrinsic (e.g., age, gender, race/ethnicity, household income, comorbidities) and extrinsic (e.g., HIV stigma and social support) contextual factors.” 

• Lazor et al. A comprehensive profile of cannabis consumers living with HIV after legalization: The Ontario Cannabis and HIV Survey.
  
  “Over half of the study participants reported consumption of cannabis for recreational purposes, while only 12% reported medical use. Trends in types of product consumed were similar for both recreational and medicinal use purposes aside from edibles, hash, beverages and concentrates, which were more commonly used recreationally, and liquid oil drops and topicals, which were more commonly used medicinally.”

• Lazor et al. Feasibility of Evaluating Standard THC Units (STU) Across Product Types Among People Living with HIV in Ontario, Canada.
  
  “Calculation of a STU by product type was feasible using THC content ranges and amounts consumed, and we saw participants reporting a broad range of STUs across different cannabis product types.”

Oral Presentations

• Light at al. Self-reported anal cancer screening prior to release of new clinical guidelines: Results from the Ontario HIV Treatment Network (OHTN) Cohort Study.
  
  “New international guidelines recommend annual anal cancer screening for people living with HIV aged 35+ for MSM and age 45+ for all others. Data from the OCS show that in 2023, the year prior to the release of these guidelines, the proportion reporting an anal cytology (Pap) test were 27% for MSM, 5.3% for women, and 4.1% for heterosexual men. Implementation of the guidelines requires scaling up screening practice among MSM and targeted efforts to introduce screening to women and heterosexual men for whom it will likely be new practice.”

• Xi et al. Trends in Annual Healthcare Costs among People Living with HIV in Ontario, Canada from 2003 to 2018: Results from a Population-Based Study.
  
  “Healthcare cost trends for people living with HIV in Ontario have fluctuated over time, primarily reflecting changes in medication costs. Differential healthcare costs across populations warrants further study, including the role of delayed diagnoses and care.”

• Rueda et al. Investigating intersectional inequalities of gender, age, and race in cannabis use among Ontarians living with HIV: the Ontario HIV Treatment Network Cohort Study.
  
  “This was a first application of an Intersectional Multi-Level Analysis of Individual Heterogeneity and Discriminatory Accuracy (I-MAIHDA) using data from the OHTN Cohort Study. Findings showed that the contribution of people’s social identities on frequency of cannabis use was largely additive, but for some there was also an interaction effect which either enhanced or suppressed frequency of use, highlighting a need for tailored messaging and equitable resources and supports.”

• Su et al. Dual Trajectories of Disability and Physical Activity in Adults Aging with HIV: Insights from a Population-Based Longitudinal Study in Ontario, Canada.
  
  “Disability (no disability; low disability; medium disability; high disability) and physical activity (barely active; decreasing activity; increasing activity; highly active) each followed four distinct trajectories over four years and were interconnected among adults aging with HIV. These findings highlight the importance of ongoing monitoring and the potential role of physical activity in mitigating disability among adults living with HIV.”

Working with the OCS

How can I access OHTN Cohort Study data? The OHTN Cohort Study encourages new and past collaborators to submit proposals for analysis projects. The following 5 steps are required to complete the Research Application Process (RAP).

Step 1: Research idea
We know that developing a research idea can be challenging especially when one is not familiar with the scope and limitations of the OHTN Cohort Study. In an effort to support collaborators to develop focused research questions we ask that they submit an OHTN Cohort Study Concept Sheet to the OHTN Cohort Study research coordinator. Following review and approval of an OHTN Cohort Study Concept Sheet, collaborator(s) may submit a “Data Scan Request” form to obtain aggregate-level OHTN Cohort Study data to assess study feasibility.

Step 2: Developing an OCS Project Proposal
Collaborators will be encouraged to complete an OCS Project Proposal only after the review and approval of an OCS Concept Sheet. All Research Project Proposals must contain the information set out in the OCS Research Proposal Form, in particular, whether OHTN Cohort Study data are sought in Standard Release or Conditional Release format. It’s important to note that the Research Project Proposal must be eligible for implicit approval by the research ethics board (REB) of the University of Toronto or have obtained research ethics board (REB) review and approval from the University of Toronto.

Step 3: OHTN Cohort Study: Scientific Review of Research Project Proposals
The OHTN Cohort Study Scientific Steering Committee conducts scientific review to ensure that the research objectives and the analytical plan of each proposal are scientifically feasible and methodologically sound. The Scientific Steering Committee will also assess the necessity of each data element requested in the Research Project proposal to assess whether the proposal presents a risk of residual disclosure and, if so, to recommend how any such risk may be addressed. A Research Project Proposal that has obtained research ethics board (REB) approval from the University of Toronto may be exempted from OHTN’s scientific review by the OHTN Cohort Study Principal Investigator. Following scientific review, the Scientific Steering Committee may recommend the Research Project Proposal for approval as proposed or with revision(s). A proposal will proceed for review by the Governance Committee if and as approved by the Scientific Steering Committee.

Step 4: Community Review by OHTN Cohort Study Governance Committee
The purpose of community review by the Governance Committee is to review each Research Project Proposal following successful scientific review for ethical considerations and for consistency with the OHTN and OHTN Cohort Study’ guiding principles. The Governance Committee may, approve the Research Project Proposal as proposed or with comments and/or revision(s). Once approved, a Research Project Proposal is a “Research Project”.

Step 5: Release of OHTN Cohort Study Data
The OHTN will disclose to Research Project PIs (or their Research Project Team members) only that OHTN Cohort Study Data which has been approved for collection, use and/or disclosure in accordance with steps 3 and 4 above. The OHTN will disclose approved OHTN Cohort Study Data in a release format that provides OHTN Cohort Study participants with the greatest possible protection of their privacy and confidentiality while still meeting the administrative and/or research purposes for which the collection, use and/or disclosure of OHTN Cohort Study data have been authorized.

Working with Indigenous Data

The OCS encourages researchers to conduct analysis on key populations, including those communities disproportionately impacted by HIV. In order to meet current guidance regarding Indigenous data, the OCS has implemented a specific review process for studies of Indigenous Peoples, or that include research questions that will be analyzed by Indigeneity. To submit a research study with a specific focus on Indigenous Peoples, please use the Indigenous Research Proposal Form.

In addition to the steps outlined above, an Indigenous Research study must be reviewed by the Indigenous Data Governance Circle.

Further, preliminary analyses must be submitted to the Indigenous Data Governance Circle before publication or dissemination.

For proposals that include a sub-analysis by group, analyses about Indigenous Peoples must be submitted for review by the Indigenous Data Governance Circle before publication. For more information contact [email protected].

Working with the OCS at ICES

The OCS provides a linked data set to the Institute for Clinical Evaluative Sciences (ICES). Working with the OCS allows for the inclusion of provincial administrative data in an OCS analysis. To work with the OCS at ICES, you must receive approval from the OCS governance committee and submit the project for approval at ICES.

OHTN Cohort Study Questionnaire

The OHTN Cohort Study questionnaire was introduced in 2007 to augment the scope of data collected through clinical chart extraction. Participants are requested to complete an interviewer administered questionnaire yearly. The questionnaire is modular allowing the OHTN Cohort Study the flexibility to ask different questions every year. The base interview module takes approximately 60 minutes to complete. Each year there may be additional sections which are added up to a time maximum of 60 minutes. Participant responses are collected electronically, with no identifying information. Questionnaires are offered in English, French, and Spanish, depending on the capacity of the site.

The list of current topics are here. If you’d like a copy of the full questionnaire, please email [email protected].