Trends in discharges from the HIV/AIDS ward at a tertiary Canadian Hospital from 2005 to 2014.

Advances in HIV therapies have transformed HIV infection into a manageable chronic disease. Accordingly, hospital admission trends among people living with HIV may have evolved over time. This study describes discharge diagnoses from the dedicated HIV/AIDS ward at St. Paul's Hospital in Vancouver, Canada. A retrospective database review of admissions to the HIV/AIDS ward between 1 July 2005 and 30 June 2014 was conducted. Primary discharge diagnoses were manually categorized by condition and reviewed by two physicians. Data were analysed in 12-month intervals. Trends were fitted using generalized estimating equations. A total of 1595 individuals with 3919 admissions were included. The median age was 46 years, 77.1% identified as male, 63.6% had a history of injection drug use (IDU) and 61.8% had a history of hepatitis C virus exposure. The most common reasons for admission included non-opportunistic respiratory tract infections (18.2%), cellulitis (7.3%), gastroenteritis (6.0%), endocarditis/bacteremia (4.9%) and bone/joint infections (3.5%). The proportion of admissions attributable to opportunistic infections declined from 16.2% in 2005 to 5.5% in 2014. Over this period, the proportion of individuals on antiretroviral therapy and with virologic suppression increased (odds ratio 1.19 [95% confidence interval 1.16, 1.23] and 1.22 [95% confidence interval 1.17, 1.26], respectively). These results demonstrate a decline in admissions related to opportunistic infections but increased admissions due to other infections among people living with HIV. Preventive and outpatient care for respiratory infections and complications of IDU may further improve health care outcomes and decrease hospital admissions in this setting.

Health-related quality-of-life and receipt of women-centered HIV care among women living with HIV in Canada.

We measured health-related quality of life (HRQOL) using the SF-12 among women living with HIV (WLWH) in Canada between August 2013 and May 2015. We investigated differences by perceived receipt of women-centered HIV care (WCHC), assessed using an evidence-based definition with a 5-point Likert item: "Overall, I think that the care I have received from my HIV clinic in the last year has been women-centered" (dichotomized into agree vs. disagree/neutral). Of 1308 participants, 26.3 percent were from British Columbia, 48.2 percent from Ontario, and 25.5 percent from Québec. The median age was 43 years (interquartile range = 36-51). Most (42.2 percent) were White, 29.4 percent African/Caribbean/Black, and 21.0 percent Indigenous. Overall, 53.4 percent perceived having received WCHC. Mean physical and mental HRQOL scores were 43.8 (standard deviation [SD] = 14.4) and 41.7 (SD = 14.2), respectively. Women perceiving having received WCHC had higher mean physical (44.7; SD = 14.0) and mental (43.7; SD = 14.1) HRQOL scores than those not perceiving having received WCHC (42.9; SD = 14.8 and 39.5; SD = 14.0, respectively; p < .001). In multivariable linear regression, perceived WCHC was associated with higher mental (ß = 3.48; 95 percent confidence interval: 1.90, 5.06) but not physical HRQOL. Improving HRQOL among Canadian WLWH, which was lower than general population estimates, is needed, including examining the potential of WCHC as an effective model of clinical care.

Pathways From HIV-Related Stigma to Antiretroviral Therapy Measures in the HIV Care Cascade for Women Living With HIV in Canada.

BACKGROUND: Associations between HIV-related stigma and reduced antiretroviral therapy (ART) adherence are widely established, yet the mechanisms accounting for this relationship are underexplored. There has been less attention to HIV-related stigma and its associations with ART initiation and current ART use. We examined pathways from HIV-related stigma to ART initiation, current ART use, and ART adherence among women living with HIV in Canada. METHODS: We used baseline survey data from a national cohort of women living with HIV in Canada (n = 1425). Structural equation modeling using weighted least squares estimation methods was conducted to test the direct effects of HIV-related stigma dimensions (personalized, negative self-image, and public attitudes) on ART initiation, current ART use, and 90% ART adherence, and indirect effects through depression and HIV disclosure concerns, adjusting for sociodemographic factors. RESULTS: In the final model, the direct paths from personalized stigma to ART initiation (ß = -0.104, P < 0.05) and current ART use (ß = -0.142, P < 0.01), and negative self-image to ART initiation (ß = -0.113, P < 0.01) were significant, accounting for the mediation effects of depression and HIV disclosure concerns. Depression mediated the pathways from personalized stigma to ART adherence, and negative self-image to current ART use and ART adherence. Final model fit indices suggest that the model fit the data well [χ(25) = 90.251, P < 0.001; comparative fit index = 0.945; root-mean-square error of approximation = 0.044]. CONCLUSIONS: HIV-related stigma is associated with reduced likelihood of ART initiation and current ART use, and suboptimal ART adherence. To optimize the benefit of ART among women living with HIV, interventions should reduce HIV-related stigma and address depression.

Cohort profile: The Canadian HIV Women's Sexual and Reproductive Health Cohort Study (CHIWOS).

Globally, women are at increased vulnerability to HIV due to biological, social, structural, and political reasons. Women living with HIV also experience unique issues related to their medical and social healthcare, which makes a clinical care model specific to their needs worthy of exploration. Furthermore, there is a dearth of research specific to women living with HIV. Research for this population has often been narrowly focused on pregnancy-related issues without considering their complex structural inequalities, social roles, and healthcare and biological needs. For these reasons, we have come together, as researchers, clinicians and community members in Canada, to develop the Canadian HIV Women's Sexual and Reproductive Health Cohort Study (CHIWOS) to investigate the concept of women-centred HIV care (WCHC) and its impact on the overall, HIV, women's, mental, sexual, and reproductive health outcomes of women living with HIV. Here, we present the CHIWOS cohort profile, which describes the cohort and presents preliminary findings related to perceived WCHC. CHIWOS is a prospective, observational cohort study of women living with HIV in British Columbia (BC), Ontario, and Quebec. Two additional Canadian provinces, Saskatchewan and Manitoba, will join the cohort in 2018. Using community-based research principles, CHIWOS engages women living with HIV throughout the entire research process meeting the requirements of the 'Greater Involvement of People living with HIV/AIDS'. Study data are collected through an interviewer-administered questionnaire that uses a web-based platform. From August 2013 to May 2015, a total of 1422 women living with HIV in BC, Ontario, and Quebec were enrolled and completed the baseline visit. Follow-up interviews are being conducted at 18-month intervals. Of the 1422 participants at baseline, 356 were from BC (25%), 713 from Ontario (50%), 353 from Quebec (25%). The median age of the participants at baseline was 43 years (range, 16-74). 22% identified as Indigenous, 30% as African, Caribbean or Black, 41% as Caucasian/White, and 7% as other ethnicities. Overall, 83% of women were taking antiretroviral therapy at the time of the baseline interview and of them, 87% reported an undetectable viral load. Of the 1326 women who received HIV medical care in the previous year and responded to corresponding questions, 57% (95% CI: 54%-60%) perceived that the care they received from their primary HIV doctor had been women-centred. There were provincial and age differences among women who indicated that they received WCHC versus not; women from BC or Ontario were more likely to report WCHC compared to participants in Quebec. They were also more likely to be younger. CHIWOS will be an important tool to develop care models specific for women living with HIV. Moreover, CHIWOS is collecting extensive information on socio-demographics, social determinants of health, psychological factors, and sexual and reproductive health and offers an important platform to answer many relevant research questions for and with women living with HIV. Information on the cohort can be found on the study website (http://www.chiwos.ca).

Is there a rural/urban gap in the quality of HIV care for treatment-naïve HIV-positive individuals initiating antiretroviral therapy in British Columbia?

Rurally located people living with HIV (PLWH) face unique challenges associated with remoteness that may negatively affect their HIV care outcomes. The Programmatic Compliance Score (PCS) has been used previously as a quality of care metric, and is predictive of mortality for treatment-naïve individuals initiating combination antiretroviral therapy (cART). This study looked at whether the rurality of PLWH impacted their PCS. PCS was calculated for PLWH (≥19 years old) initiating cART in British Columbia between 2000 and 2013. Rurality was determined at the time of cART initiation using two methodologies: (1) a categorical postal code method; and (2) the General Practice Rurality Index (GPRI), a score representing an individual's degree of rurality. Ordinal logistic regression modeling was used to assess the relationship between rurality and PCS. Among 4616 PLWH with an evaluable PCS, 176 were classified as rural and 3512 as urban (928 had an unknown postal code). After adjusting for age, sex, hepatitis C status, Indigenous ancestry, and year of cART initiation, categorical rurality was not associated with a worse PCS (adjusted odds ratio (AOR) 1.04; 95% CI: 0.77-1.39). However, an increasing degree of rurality was associated with a worse PCS (AOR (per 10 increase in GPRI) 1.13; 95% CI: 1.06-1.20). Given that a poor PCS has been shown to be predictive of all-cause mortality for individuals initiating cART, strategies to improve access to HIV care for rural individuals should be evaluated.

Rates and predictors of injury in a population-based cohort of people living with HIV.

OBJECTIVES: Injuries are responsible for 10% of the global burden of disease; however, the epidemiology of injury among people living with HIV (PLHIV) has not been well elucidated. This study seeks to characterize rates and predictors of injury among PLHIV compared to the general population in British Columbia (BC), Canada. DESIGN: A population-based dataset was created via linkage between the BC Centre for Excellence in HIV/AIDS and PopulationDataBC. METHODS: PLHIV aged 20 years and older were compared to a random 10% sample of the adult general population. The International Classification of Diseases 9 and 10 codes were used to classify unintentional and intentional injuries based on the external cause of the injury from 1996 to 2013. Generalized estimating equation (GEE) Poisson regression models were fit to estimate the effect of HIV status on rates of unintentional and intentional injury, and to identify correlates of injury among PLHIV. RESULTS: The crude incidence rate of unintentional injury was 18.56/1000 person-years [95% confidence interval (CI) 17.77-19.39] among PLHIV and 8.51/1000 person-years (95% CI 8.42-8.59) in the general population. Among PLHIV, 13.45% of deaths were due to injury, compared to 5.52% of deaths in the general population. In adjusted models, PLHIV were more likely to report unintentional (incidence rate ratio 1.42, 95% CI 1.32-1.52) and intentional injury (incidence rate ratio 1.93, 95% CI 1.70-2.18) compared to the general population. CONCLUSIONS: We identified elevated rates of intentional and unintentional injury among PLHIV. Injuries are largely preventable; as such, targeted efforts are needed to decrease the burden of injury-related disability and death among PLHIV.

Sexual inactivity and sexual satisfaction among women living with HIV in Canada in the context of growing social, legal and public health surveillance.

INTRODUCTION: Women represent nearly one-quarter of the 71,300 people living with HIV in Canada. Within a context of widespread HIV-related stigma and discrimination and on-going risks to HIV disclosure, little is known about the influence of growing social, legal and public health surveillance of HIV on sexual activity and satisfaction of women living with HIV (WLWH). METHODS: We analyzed baseline cross-sectional survey data for WLWH (≥16 years, self-identifying as women) enrolled in the Canadian HIV Women's Sexual and Reproductive Health Cohort Study (CHIWOS), a multisite, longitudinal, community-based research study in British Columbia (BC), Ontario (ON) and Quebec (QC). Sexual inactivity was defined as no consensual sex (oral or penetrative) in the prior six months, excluding recently postpartum women (≤6 months). Satisfaction was assessed using an item from the Sexual Satisfaction Scale for Women. Multivariable logistic regression analysis examined independent correlates of sexual inactivity. RESULTS: Of 1213 participants (26% BC, 50% ON, 24% QC), median age was 43 years (IQR: 35, 50). 23% identified as Aboriginal, 28% as African, Caribbean and Black, 41% as White and 8% as other ethnicities. Heterosexual orientation was reported by 87% of participants and LGBTQ by 13%. In total, 82% were currently taking antiretroviral therapy (ART), and 77% reported an undetectable viral load (VL<40 copies/mL). Overall, 49% were sexually inactive and 64% reported being satisfied with their current sex lives, including 49% of sexually inactive and 79% of sexually active women (p<0.001). Sexually inactive women had significantly higher odds of being older (AOR=1.06 per year increase; 95% CI=1.05-1.08), not being in a marital or committed relationship (AOR=4.34; 95% CI=3.13-5.88), having an annual household income below $20,000 CAD (AOR: 1.44; 95% CI=1.08-1.92), and reporting high (vs. low) HIV-related stigma (AOR=1.81; 95% CI=1.09-3.03). No independent association was found with ART use or undetectable VL. CONCLUSIONS: Approximately half of WLWH in this study reported being sexually inactive. Associations with sexual dissatisfaction and high HIV-related stigma suggest that WLWH face challenges navigating healthy and satisfying sexual lives, despite good HIV treatment outcomes. As half of sexually inactive women reported being satisfied with their sex lives, additional research is required to determine whether WLWH are deliberately choosing abstinence as a means of resisting surveillance and disclosure expectations associated with sexual activity. Findings underscore a need for interventions to de-stigmatize HIV, support safe disclosure and re-appropriate the sexual rights of WLWH.

The causal effect of opioid substitution treatment on HAART medication refill adherence.

BACKGROUND: People who inject drugs (PWID) account for roughly 13% of the prevalent HIV/AIDS population outside of sub-Saharan Africa, and access to opioid substitution treatment (OST) is limited in many settings globally. OST likely facilitates access to HAART, yet sparse evidence is available to support this hypothesis. Our objective was to determine the causal impact of OST exposure on HAART adherence among HIV-positive PWID in a Canadian setting. METHODS: We executed a retrospective cohort study using linked population-level data for British Columbia, Canada (January 1996-March 2010). We considered HIV-positive PWID after meeting HAART initiation criteria. A marginal structural model was estimated on a monthly timescale using inverse probability of treatment weights. The primary outcome was 95% HAART adherence, according to pharmacy refill compliance. Exposure to OST was defined as 95% of OST receipt, and we controlled for a range of fixed and time-varying covariates. RESULTS: Our study included 1852 (63.3%) HIV-positive PWID with a median follow-up of 5.5 years; 34% were female and 39% had previously accessed OST. The baseline covariate-adjusted odds of HAART adherence following OST exposure was 1.96 (95% confidence interval: 1.72-2.24), although the adjusted odds estimated within the marginal structural model was 1.68 (1.48-1.92). Findings were robust to sensitivity analyses on model specification. CONCLUSION: In a setting characterized by universal healthcare and widespread access to both office-based OST and HAART, OST substantially increased the odds of HAART adherence. This underlines the need to address barriers to OST globally to reduce the disease burden of both opioid dependence and HIV/AIDS.

The impact of clinical, demographic and risk factors on rates of HIV transmission: a population-based phylogenetic analysis in British Columbia, Canada.

BACKGROUND: The diversification of human immunodeficiency virus (HIV) is shaped by its transmission history. We therefore used a population based province wide HIV drug resistance database in British Columbia (BC), Canada, to evaluate the impact of clinical, demographic, and behavioral factors on rates of HIV transmission. METHODS: We reconstructed molecular phylogenies from 27,296 anonymized bulk HIV pol sequences representing 7747 individuals in BC-about half the estimated HIV prevalence in BC. Infections were grouped into clusters based on phylogenetic distances, as a proxy for variation in transmission rates. Rates of cluster expansion were reconstructed from estimated dates of HIV seroconversion. RESULTS: Our criteria grouped 4431 individuals into 744 clusters largely separated with respect to risk factors, including large established clusters predominated by injection drug users and more-recently emerging clusters comprising men who have sex with men. The mean log10 viral load of an individual's phylogenetic neighborhood (composed of 5 other individuals with shortest phylogenetic distances) increased their odds of appearing in a cluster by >2-fold per log10 viruses per milliliter. CONCLUSIONS: Hotspots of ongoing HIV transmission can be characterized in near real time by the secondary analysis of HIV resistance genotypes, providing an important potential resource for targeting public health initiatives for HIV prevention.

Costs of health resource utilization among HIV-positive individuals in British Columbia, Canada: results from a population-level study.

BACKGROUND: Through delayed HIV disease progression, highly active antiretroviral therapy (HAART) may reduce direct medical costs, thus at least partially offsetting therapy costs. Recent findings regarding the secondary preventive benefits of HAART necessitate careful consideration of funding allocations for HIV/AIDS care. Our objective is to estimate non-HAART direct medical costs at different levels of disease progression and over time in British Columbia, Canada. METHODS: We considered the population of individuals with HIV/AIDS within a set of linked disease registries and health administrative databases (N = 11,836) from 1996 to 2010. Costs of hospitalization, physician billing, diagnostic testing and non-HAART medications were calculated in 2010 Canadian dollars. Effects of covariates on quarterly costs were assessed with a two-part model with logit for probability of non-zero costs and a generalized linear model (GLM). Net effects of CD4 strata on direct non-HAART medical costs were evaluated over time during the study period. RESULTS: Compared with person-quarters in which CD4 >500/mm(3), costs were Can$185 (95 % confidence interval [CI] 132-239) greater for CD4 350-500/mm(3), Can$441 (95 % CI 366-516) greater for CD4 200-350/mm(3) and Can$1,173 (95 % CI 1,051-1,294) greater when CD4 <200/mm(3). Prior to HIV care initiation, individuals incurred costs Can$385 (95 % CI 283-487) greater than in periods with CD4 >500/mm(3). Hospitalization comprised the majority of the increment in costs amongst those with no measured CD4. Evaluated at CD4 state conditional means, those with CD4 <200/mm(3) incurred quarterly costs of Can$5,781 (95 % CI 4,716-6,846) versus Can$1,307 (95 % CI 1,154-1,460; p < 0.001) for CD4 ≥500/mm(3) in 2010. CONCLUSION: Non-HAART direct medical costs were substantially lower for individuals during periods of sustained virologic suppression and high CD4 count. HIV treatment and prevention evaluations require detailed health resource use data to inform funding allocation decisions.

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.

Process monitoring of an HIV treatment as prevention program in British Columbia, Canada.

BACKGROUND: In light of accumulated scientific evidence of the secondary preventive benefits of antiretroviral therapy, a growing number of jurisdictions worldwide have formally started to implement HIV Treatment as Prevention (TasP) programs. To date, no gold standard for TasP program monitoring has been described. Here, we describe the design and methods applied to TasP program process monitoring in British Columbia (BC), Canada. METHODS: Monitoring indicators were selected through a collaborative and iterative process by an interdisciplinary team including representatives from all 5 regional health authorities, the BC Centre for Disease Control (BCCDC), and the BC Centre for Excellence in HIV/AIDS (BC-CfE). An initial set of 36 proposed indicators were considered for inclusion. These were ranked on the basis of 8 criteria: data quality, validity, scientific evidence, informative power of the indicator, feasibility, confidentiality, accuracy, and administrative requirement. The consolidated list of indicators was included in the final monitoring report, which was executed using linked population-level data. RESULTS: A total of 13 monitoring indicators were included in the BC TasP Monitoring Report. Where appropriate, indicators were stratified by subgroups of interest, including HIV risk group and demographic characteristics. Six Monitoring Reports are generated quarterly: 1 for each of the regional health authorities and a consolidated provincial report. CONCLUSIONS: We have developed a comprehensive TasP process monitoring strategy using evidence-based HIV indicators derived from linked population-level data. Standardized longitudinal monitoring of TasP program initiatives is essential to optimize individual and public health outcomes and to enhance program efficiencies.

Cohort profile: Seek and treat for the optimal prevention of HIV/AIDS in British Columbia (STOP HIV/AIDS BC).

The Seek and Treat for Optimal Prevention of HIV/AIDS (STOP HIV/AIDS) cohort is a census of all identified HIV-positive individuals in the province of British Columbia. It was formed through the linkage of nine provincial treatment, surveillance and administrative databases. This open cohort allows for bidirectional analyses from 1996 onward and is refreshed annually. Extensive data collection for cohort members includes demographic information, detailed clinical and laboratory data, complete prescription drug use including antiretroviral agents, and information on health service utilization encompassing inpatient and outpatient care, addictions treatment and palliative care. This cohort provides an unprecedented opportunity to evaluate, over an extended time period, patterns and determinants of key outcomes including engagement in the cascade of HIV care from diagnosis to treatment to viral suppression as well as monitoring trends in medical costs, health outcomes and other key healthcare delivery indicators at a population level with wide-ranging, high-quality data. The overall purpose of these activities is to enable the development and implementation of strategically targeted interventions to improve access to testing, care and treatment for all HIV-positive individuals living in British Columbia.

The cascade of HIV care in British Columbia, Canada, 1996-2011: a population-based retrospective cohort study.

BACKGROUND: The cascade of HIV care has become a focal point for implementation efforts to maximise the individual and public health benefits of antiretroviral therapy. We aimed to characterise longitudinal changes in engagement with the cascade of HIV care in British Columbia, Canada, from 1996 to 2011. METHODS: We used estimates of provincial HIV prevalence from the Public Health Agency of Canada and linked provincial population-level data to define, longitudinally, the numbers of individuals in each of the eight stages of the cascade of HIV care (HIV infected, diagnosed, linked to HIV care, retained in HIV care, highly active antiretroviral therapy (HAART) indicated, on HAART, adherent to HAART, and virologically suppressed) in British Columbia from 1996 to 2011. We used sensitivity analyses to determine the sensitivity of cascade-stage counts to variations in their definitions. FINDINGS: 13,140 people were classified as diagnosed with HIV/AIDS in British Columbia during the study period. We noted substantial improvements over time in the proportions of individuals at each stage of the cascade of care. Based on prevalence estimates, the proportion of unidentified HIV-positive individuals decreased from 49·0% (estimated range 36·2-57·5%) in 1996 to 29·0% (11·6-40·7%) in 2011, and the proportion of HIV-positive people with viral suppression reached 34·6% (29·0-43·1%) in 2011. INTERPRETATION: Careful mapping of the cascade of care is crucial to understanding what further efforts are needed to maximise the beneficial effects of available interventions and so inform efforts to contain the spread of HIV/AIDS. FUNDING: British Columbia Ministry of Health, US National Institute on Drug Abuse (National Institutes of Health).

Application and validation of case-finding algorithms for identifying individuals with human immunodeficiency virus from administrative data in British Columbia, Canada.

OBJECTIVE: To define a population-level cohort of individuals infected with the human immunodeficiency virus (HIV) in the province of British Columbia from available registries and administrative datasets using a validated case-finding algorithm. METHODS: Individuals were identified for possible cohort inclusion from the BC Centre for Excellence in HIV/AIDS (CfE) drug treatment program (antiretroviral therapy) and laboratory testing datasets (plasma viral load (pVL) and CD4 diagnostic test results), the BC Centre for Disease Control (CDC) provincial HIV surveillance database (positive HIV tests), as well as databases held by the BC Ministry of Health (MoH); the Discharge Abstract Database (hospitalizations), the Medical Services Plan (physician billing) and PharmaNet databases (additional HIV-related medications). A validated case-finding algorithm was applied to distinguish true HIV cases from those likely to have been misclassified. The sensitivity of the algorithms was assessed as the proportion of confirmed cases (those with records in the CfE, CDC and MoH databases) positively identified by each algorithm. A priori hypotheses were generated and tested to verify excluded cases. RESULTS: A total of 25,673 individuals were identified as having at least one HIV-related health record. Among 9,454 unconfirmed cases, the selected case-finding algorithm identified 849 individuals believed to be HIV-positive. The sensitivity of this algorithm among confirmed cases was 88%. Those excluded from the cohort were more likely to be female (44.4% vs. 22.5%; p<0.01), had a lower mortality rate (2.18 per 100 person years (100PY) vs. 3.14/100PY; p<0.01), and had lower median rates of health service utilization (days of medications dispensed: 9745/100PY vs. 10266/100PY; p<0.01; days of inpatient care: 29/100PY vs. 98/100PY; p<0.01; physician billings: 602/100PY vs. 2,056/100PY; p<0.01). CONCLUSIONS: The application of validated case-finding algorithms and subsequent hypothesis testing provided a strong framework for defining a population-level cohort of HIV infected people in BC using administrative databases.