Research Papers

@article{A2021,
title = {Estimating an individual-level deprivation index for HIV/HCV coinfected persons in Canada},
author = {A, Palayew; AM, Schmidt; S, Saeed; CL Cooper; A, Wong; V, Martel-Laferrière; S, Walmsley; J, Cox; MB, Klein;},
url = {https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0249836},
doi = {10.1371/journal.pone.0249836},
year = {2021},
date = {2021-04-19},
journal = {PLOS One},
abstract = {Background
HIV-HCV coinfected individuals are often more deprived than the general population. However, deprivation is difficult to measure, often relying on aggregate data which does not capture individual heterogeneity. We developed an individual-level deprivation index for HIV-HCV co-infected persons that encapsulated social, material, and lifestyle factors.

Methods
We estimated an individual-level deprivation index with data from the Canadian Coinfection Cohort, a national prospective cohort study. We used a predetermined process to select 9 out of 19 dichotomous variables at baseline visit to include in the deprivation model: income >$1500/month; education >high school; employment; identifying as gay or bisexual; Indigenous status; injection drug use in last 6 months; injection drug use ever; past incarceration, and past psychiatric hospitalization. We fitted an item response theory model with: severity parameters (how likely an item was reported), discriminatory parameters, (how well a variable distinguished index levels), and an individual parameter (the index). We considered two models: a simple one with no provincial variation and a hierarchical model by province. The Widely Applicable Information Criterion (WAIC) was used to compare the fitted models. To showcase a potential utility of the proposed index, we evaluated with logistic regression the association of the index with non-attendance to a second clinic visit (as a proxy for disengagement) and using WAIC compared it to a model containing all the individual parameters that compose the index as covariates.

Results
We analyzed 1547 complete cases of 1842 enrolled participants. According to the WAIC the hierarchical model provided a better fit when compared to the model that does not consider the individual’s province. Values of the index were similarly distributed across the provinces. Overall, past incarceration, education, and unemployment had the highest discriminatory parameters. However, in each province different components of the index were associated with being deprived reflecting local epidemiology. For example, Saskatchewan had the highest severity parameter for Indigenous status while Quebec the lowest. For the secondary analysis, 457 (30%) failed to attend a second visit. A one-unit increase in the index was associated with 17% increased odds (95% credible interval, 2% to 34%) of not attending a second visit. The model with just the index performed better than the model with all the components as covariates in terms of WAIC.

Conclusion
We estimated an individual-level deprivation index in the Canadian Coinfection cohort. The index identified deprivation profiles across different provinces. This index and the methodology used may be useful in studying health and treatment outcomes that are influenced by social disparities in co-infected Canadians. The methodological approach described can be used in other studies with similar characteristics.},
keywords = {Hepatitis C virus, HIV, HIV-HCV co-infection, Injection drug use, People who inject drugs},
pubstate = {published},
tppubtype = {article}
}

@article{T2018b,
title = {Injection drug use, food insecurity, and HIV-HCV co-infection: a longitudinal cohort analysis},
author = {McLinden T and Moodie EEM and Harper S and Hamelin AM and Anema A and Aibibula W and Klein MB and Cox J},
url = {https://pubmed.ncbi.nlm.nih.gov/29716392/},
doi = {10.1080/09540121.2018.1465171},
year = {2018},
date = {2018-10-01},
journal = {AIDS Care},
abstract = {Injection drug use (IDU) and food insecurity (FI) are highly prevalent among individuals living with HIV-hepatitis C virus (HCV) co-infection. We quantified the association between IDU and FI among co-infected individuals using biannual data from the Canadian Co-infection Cohort (N = 608, 2012-2015). IDU (in the past six months) and IDU frequency (non-weekly/weekly in the past month) were self-reported. FI (in the past six months) and FI severity (marginal FI, moderate FI, and severe FI) were measured using the Household Food Security Survey Module. Generalized estimating equations were used to estimate risk ratios (RR) quantifying the associations between IDU, IDU frequency, and FI with Poisson regression. The associations between IDU, IDU frequency, and FI severity were quantified by relative-risk ratios (RRR) estimated with multinomial regression. At the first time-point in the analytical sample, 54% of participants experienced FI in the past six months, 31% engaged in IDU in the six months preceding the FI measure, and 24% injected drugs in the past month. After adjustment for confounding, IDU in the past six months (RR = 1.15, 95% confidence interval [CI] = 1.04-1.28) as well as non-weekly (RR = 1.15, 95% CI = 1.02-1.29) and weekly IDU (RR = 1.21, 95% CI = 1.07-1.37) in the past month are associated with FI. Weekly IDU in the past month is also strongly associated with severe FI (RRR = 2.68, 95% CI = 1.47-4.91). Our findings indicate that there is an association between IDU and FI, particularly weekly IDU and severe FI. This suggests that reductions in IDU may mitigate FI, especially severe FI, in this vulnerable subset of the HIV-positive population.},
keywords = {Food insecurity, Hepatitis C virus, HIV, Injection drug use},
pubstate = {published},
tppubtype = {article}
}

@article{T2017b,
title = {Injection Drug Use, Unemployment, and Severe Food Insecurity Among HIV-HCV Co-Infected Individuals: A Mediation Analysis},
author = {McLinden T and Moodie EEM and Hamelin AM and Harper S and Walmsley SL and Paradis G and Aibibula W and Klein MB and Cox J},
url = {https://pubmed.ncbi.nlm.nih.gov/28726043/},
doi = {10.1007/s10461-017-1850-2},
year = {2017},
date = {2017-12-01},
journal = {AIDS and Behaviour},
abstract = {Severe food insecurity (FI), which indicates reduced food intake, is common among HIV-hepatitis C virus (HCV) co-infected individuals. Given the importance of unemployment as a proximal risk factor for FI, this mediation analysis examines a potential mechanism through which injection drug use (IDU) is associated with severe FI. We used biannual data from the Canadian Co-infection Cohort (N = 429 with 3 study visits, 2012-2015). IDU in the past 6 months (exposure) and current unemployment (mediator) were self-reported. Severe FI in the following 6 months (outcome) was measured using the Household Food Security Survey Module. An overall association and a controlled direct effect were estimated using marginal structural models. Among participants, 32% engaged in IDU, 78% were unemployed, and 29% experienced severe FI. After adjustment for confounding and addressing censoring through weighting, the overall association (through all potential pathways) between IDU and severe FI was: risk ratio (RR) = 1.69 (95% confidence interval [CI] = 1.15-2.48). The controlled direct effect (the association through all potential pathways except that of unemployment) was: RR = 1.65 (95% CI = 1.08-2.53). We found evidence of an overall association between IDU and severe FI and estimated a controlled direct effect that is suggestive of pathways from IDU to severe FI that are not mediated by unemployment. Specifically, an overall association and a controlled direct effect that are similar in magnitude suggests that the potential impact of IDU on unemployment is not the primary mechanism through which IDU is associated with severe FI. Therefore, while further research is required to understand the mechanisms linking IDU and severe FI, the strong overall association suggests that reductions in IDU may mitigate severe FI in this vulnerable subset of the HIV-positive population.},
keywords = {Hepatitis C virus, HIV, Injection drug use, Severe food insecurity, Unemployment},
pubstate = {published},
tppubtype = {article}
}