Suchergebnisse

A recent article in The Lancet establishing the principles of inclusion health, highlighted substantial gaps in our understanding of the drivers of health inequalities in socially excluded groups such as people with a history of incarceration, people who experience homelessness, sex workers, people with mental illness, and people who inject drugs1. Cross-sectoral data linkage of electronic health records with services working with socially excluded groups was one of the key recommendations of this article. The magnitude of health disparities observed in people that experience social exclusion necessitates an international public health response and addressing the determinants of social exclusion has been identified as a key component of closing the gap of Indigenous disadvantage2. This symposium will establish data linkage as a key component of the inclusion health and will complement the efforts of the Pan American Health Oranization's (PAHO) Commission on Equity and Health Inequalities in the Americas.
Traditional survey methodology is costly and often results in studies that are highly parochial in nature. Due to difficulties recruiting and retaining marginalized groups, these studies are commonly forced to adopt methodological concessions, often selecting the most convenient participants (i.e., selection bias) or incurring increased rates of loss-to-follow-up (i.e., attrition bias). Conversely, global studies aimed at modelling the burden of disease are often not sufficiently nuanced to answer specific inferential research questions. Data-linkage has the potential to overcome these common biases and limitations. Thus, harmonised international data-linkage studies are an important component of the inclusion health response to identify the determinants of health inequalities in socially excluded groups and inform the global inclusion health agenda.
This symposium will bring together facilitators from three countries with extensive experience conducting data linkage studies that generate evidence on health and social inequality in socially excluded groups. Using a current multinational study as an example, barriers to international data-linkage studies, methodological solutions, and distributed approaches to generating international comparative evidence will be presented. Innovative examples of cross-sectoral approaches to linkage with social service, correctional and national survey data will be discussed. The development of a novel framework for identifying social exclusion exposures and determinants of health inequalities typically not captured in administrative health data will also be discussed. The session will conclude with a discussion aimed at forming the foundation of an international data linkage project to address these current gaps identified in the inclusion health series and best practice for translation to policy and practice to address health disparities in socially excluded groups.
References

Aldridge et al. Morbidity and mortality in homeless individuals, prisoners, sex workers, and individuals with substance use disorders in high-income countries: a systematic review and meta-analysis. The Lancet. 2017;391(10117):241-250. https://doi.org/10.1016/S0140-6736(17)31869-X
Greenwood M et al. Challenges in health equity for Indigenous peoples in Canada. The Lancet. 2018;Epub ahead of print. https://doi.org/10.1016/S0140-6736(18)30177-6

IntroductionMost chronic hepatitis B virus (HBV) infections in Canada are diagnosed among immigrants from endemic countries and lack traditional risk factors while most acute infections are usually diagnosed in Caucasian population with co-occurring risk factors. Thus, understanding geographical distribution of HBV infection by ethnicity could inform screening and care strategies.
Objectives and ApproachWe identified geographic clusters of HBV infection in British Columbia by ethnicity during the years 1990-2015 using the BC Hepatitis Testers Cohort (BC-HTC). The BC-HTC includes ~1.7 million individuals tested for HCV or HIV at the BC Public Health Laboratory or reported as a case of HCV, HIV, or HBV linked to healthcare administrative databases. We plotted maps of HBV diagnoses (acute and chronic) rate at the Dissemination Area level between 1990-2015 stratified by ethnicity and compared this distribution with injection drug use (IDU) distribution in BC.
ResultsThe distribution of HBV varied considerably by ethnicity. From 1990 to 2015, a higher rate of HBV infection was found among East Asians and Caucasians followed by South Asians and other ethnicities. East Asians with highest rates were mainly concentrated in Vancouver city, Burnaby and Richmond (Metro Vancouver) while South Asians with highest rates were mostly concentrated in urban areas in Surrey and Abbotsford. Caucasians with higher rates were clustered in Downtown Eastside in Vancouver, Surrey and Abbotsford (Metro Vancouver) and urban areas in Greater Victoria (Vancouver Island), Prince George (Northern BC) and Kamloops (Interior BC). The distribution of IDU closely followed the distribution of HBV among Caucasians but did not align with other ethnic groups.
Conclusion/ImplicationsResults highlight distinct areas of HBV infection clustering by ethnicity, which differ from areas with high IDU distribution except in Caucasians. Findings support ethnicity-based HBV screening/prevention and care services to areas with immigrants from HBV-endemic countries and integrated HBV and harm reduction services for early diagnosis and treatment in Caucasians.

ObjectivesThe COVID-19 pandemic has necessitated access to large health system datasets to inform the public health response. To meet this need, the Provincial Health Services Authority and the British Columbia (BC) Ministry of Health collaborated to create a population-based platform that integrates COVID-19 datasets with sociodemographic and administrative health data.
ApproachA BC COVID Data Library proof-of-concept was created as a cloud-based, dynamic platform composed of de-identified datasets. The BC COVID-19 Cohort (BCC19C) represents a subset composed of people accessing COVID-19 health services (e.g., testing, vaccination) and linked health histories. Provincial COVID-19 datasets are updated daily and include COVID-19 lab tests, case surveillance, vaccinations and hospitalizations/deaths. These can be linked to administrative data holdings for the BC population, which are updated weekly/monthly and include vital statistics, medications, hospital admissions, medical visits, among others. A patient matching algorithm creates unique patient keys that allows the same individual to be linked across datasets.
ResultsThe BCC19C has been used provincially to 1) support ongoing surveillance, reporting, and modelling of COVID-19; 2) describe and characterize the epidemiology of COVID-19; and 3) inform acute care planning, public health interventions and health care services in BC. Ongoing and completed BCC19C analyses include assessment of vaccine safety, vaccine effectiveness, and characteristics associated with infection and severe outcomes; use of medical visit data for syndromic surveillance and monitoring of unintended outcomes of the pandemic (e.g., mental health visits); and characterization of long-COVID. Availability of linked administrative data holdings has been crucial for identifying non-COVID control groups, measuring sociodemographics and co-morbidities, and complementing COVID-19 datasets for more complete capture of health outcomes (e.g., deaths, hospitalizations).
ConclusionsThe large scope/breadth and timeliness of the linkable datasets integrated within the COVID Data Library and the BCC19C has supported the public health response in BC. Additional linkage to other data sources will further strengthen this data platform.

AbstractIntroductionPeople living with HIV (PLWH) and/or who inject drugs may experience lower vaccine effectiveness (VE) against SARS‐CoV‐2 infection.MethodsA validated algorithm was applied to population‐based, linked administrative datasets in the British Columbia COVID‐19 Cohort (BCC19C) to ascertain HIV status and create a population of PLWH and matched HIV‐negative individuals. The study population was limited to individuals who received an RT‐PCR laboratory test for SARS‐CoV‐2 between 15 December 2020 and 21 November 2021 in BC, Canada. Any history of injection drug use (IDU) was ascertained using a validated administrative algorithm. We used a test‐negative study design (modified case−control analysis) and multivariable logistic regression to estimate adjusted VE by HIV status and history of IDU.ResultsOur analysis included 2700 PLWH and a matched population of 375,043 HIV‐negative individuals, among whom there were 351 and 103,049 SARS‐CoV‐2 cases, respectively. The proportion of people with IDU history was much higher among PLWH compared to HIV‐negative individuals (40.7% vs. 4.3%). Overall VE during the first 6 months after second dose was lower among PLWH with IDU history (65.8%, 95% CI = 43.5–79.3) than PLWH with no IDU history (80.3%, 95% CI = 62.7–89.6), and VE was particularly low at 4–6 months (42.4%, 95% CI = −17.8 to 71.8 with IDU history vs. 64.0%; 95% CI = 15.7–84.7 without), although confidence intervals were wide. In contrast, overall VE was 88.6% (95% CI = 88.2–89.0) in the matched HIV‐negative population with no history of IDU and remained relatively high at 4–6 months after second dose (84.6%, 95% CI = 83.8–85.4). Despite different patterns of vaccine protection by HIV status and IDU history, peak estimates were similar (≥88%) across all populations.ConclusionsPLWH with a history of IDU may experience lower VE against COVID‐19 infection, although findings were limited by a small sample size. The lower VE at 4–6 months may have implications for booster dose prioritization for PLWH and people who inject drugs. The immunocompromising effect of HIV, substance use and/or co‐occurring comorbidities may partly explain these findings.