High Levels of Heterogeneity in the HIV Cascade of Care across Different Population Subgroups in British Columbia, Canada

Background The HIV cascade of care (cascade) is a comprehensive tool which identifies attrition along the HIV care continuum. We executed analyses to explicate heterogeneity in the cascade across key strata, as well as identify predictors of attrition across stages of the cascade. Methods Using linked individual-level data for the population of HIV-positive individuals in BC, we considered the 2011 calendar year, including individuals diagnosed at least 6 months prior, and excluding individuals that died or were lost to follow-up before January 1st, 2011. We defined five stages in the cascade framework: HIV ‘diagnosed’, ‘linked’ to care, ‘retained’ in care, ‘on HAART’ and virologically ‘suppressed’. We stratified the cascade by sex, age, risk category, and regional health authority. Finally, multiple logistic regression models were built to predict attrition across each stage of the cascade, adjusting for stratification variables. Results We identified 7621 HIV diagnosed individuals during the study period; 80% were male and 5% were <30, 17% 30–39, 37% 40–49 and 40% were ≥50 years. Of these, 32% were MSM, 28% IDU, 8% MSM/IDU, 12% heterosexual, and 20% other. Overall, 85% of individuals ‘on HAART’ were ‘suppressed’; however, this proportion ranged from 60%–93% in our various stratifications. Most individuals, in all subgroups, were lost between the stages: ‘linked’ to ‘retained’ and ‘on HAART’ to ‘suppressed’. Subgroups with the highest attrition between these stages included females and individuals <30 years (regardless of transmission risk group). IDUs experienced the greatest attrition of all subgroups. Logistic regression results found extensive statistically significant heterogeneity in attrition across the cascade between subgroups and regional health authorities. Conclusions We found that extensive heterogeneity in attrition existed across subgroups and regional health authorities along the HIV cascade of care in B.C., Canada. Our results provide critical information to optimize engagement in care and health service delivery

Estimated HIV cascade of care by risk category in 2011 for British Columbia.

<p>*MSM  =  men who have sex men, IDU  =  history of injection drug use, MSM/IDU  =  both MSM and IDU, Other  =  blood transfusion or perinatal exposure or unknown risk group (i.e., risk factor not requested or identified).</p

Adjusted odds ratios predicting attrition between stages of the 2011 HIV cascade of care based on sex, age, transmission risk category and regional health authority for British Columbia residents diagnosed with HIV before 2011.

<p>aOR  =  adjusted odds ratio; CI  =  confidence interval; Risk group categorized as men who have sex with men (MSM), having a history of injection drug use (IDU), both MSM and IDU (MSM/IDU), heterosexual (hetero), or other (blood transfusion or perinatal exposure or unknown risk group (i.e., risk factor not requested or identified)).</p><p>Adjusted odds ratios predicting attrition between stages of the 2011 HIV cascade of care based on sex, age, transmission risk category and regional health authority for British Columbia residents diagnosed with HIV before 2011.</p

Estimated HIV cascade of care by age category and sex in 2011 for British Columbia.

<p>*Age is defined as age as of January 1^st, 2011. There were 39 HIV-diagnosed individuals with missing gender and age information; none of these individuals were linked to HIV care.</p

Estimated HIV cascade of care by Regional Health Authority in 2011 for British Columbia.

<p>*There were 148 HIV-diagnosed individuals with missing Regional Health Authority information. Of these, 106 were linked to care; 51 of those linked to HIV care were retained in care; 24 of those retained in care were on antiretrovirals (ARVs) and 14 of those on ARV were suppressed.</p

Estimated HIV cascade of care overall and by sex in 2011 for British Columbia.

<p>*There were 39 HIV-diagnosed individuals with missing sex information; none of these individuals were linked to HIV care.</p

HIV Cascade of Care Definitions.

<p>HIV Cascade of Care Definitions.</p