Prevalence of Hepatitis B in Canadian First-Time Blood Donors: Association with Social Determinants of Health.

Hepatitis B is transmitted sexually, by blood contact, and vertically from mother to child. Chronic hepatitis B is often seen in immigrants from higher-prevalence countries and their Canadian-born children. We assessed the relationship between hepatitis B and social determinants of health. Included were 1,539,869 first-time Canadian blood donors from April 2005 to December 2022. All donations were tested for hepatitis B markers. Logistic regression was fit with chronic hepatitis B as the dependent variable and age, sex, year, and ethnocultural composition and material deprivation quintiles as independent variables. Chronic hepatitis B prevalence was 47.5/100,000 (95% CI 41.5-53.5, years 2017-2022). Chronic hepatitis B prevalence was elevated in males, older age groups, and those living in more materially deprived and higher ethnocultural neighbourhoods. Of 212,518 donors from 2020 to 2022 with race/ethnicity data, chronic hepatitis B prevalence was highest in East Asians. The findings are consistent with infections in immigrants, acquired in their country of origin, in their Canadian-born children and in those with other risks. As blood donors are a low-risk population unaware of their infection and unlikely to seek testing, our results highlight the ongoing public health challenges of diagnosing chronic hepatitis B and treating it when appropriate.

Prevalence of human T-cell lymphotropic virus-1/2 in Canada over 33 years: A unique contribution of blood donors to public health surveillance.

OBJECTIVES: Estimate HTLV-1/2 (human T-cell lymphotropic viruses) prevalence in Canadian blood donors and the association of demographic variables with infection and their corresponding risk factors. METHODS: First-time blood donors in all Canadian provinces (except Quebec) from 1990 to 2022 were included. Blood samples were tested for HTLV-1/2 by enzyme-linked immunoassay, confirmed by Western blot. Multivariable logistic regression with year, age group, sex, region, neighbourhood material deprivation, and ethnocultural composition indices predicted HTLV-1/2. Since 2005, all HTLV-1/2-positive donors (cases) were invited to participate in a risk factor interview, and 4 non-positive donors (controls per case) were matched for age, sex, and region. Case-control predictors of HTLV-1/2 were analyzed using logistic regression. RESULTS: There were 3,085,554 first-time donors from 1990 to 2022. HTLV-1/2 prevalence remained low (12 per 100,000 in 2022, 95% CI 6.4-23.5). The odds ratios predicting HTLV-1/2 were higher in females (2.0, 95% CI 1.5-2.6), older age groups (50 + ; 6.3, 95% CI 4.3-9.2), British Columbia and Ontario, those materially deprived (1.9, 95% CI 1.2-2.9), and those in ethnocultural neighbourhoods (7.5, 95% CI 3.2-17.3). Most HTLV-1/2 in Ontario was HTLV-1, whereas in British Columbia half were HTLV-2. Forty-three of 149 (28.8%) cases and 172 of 413 (41.6%) controls completed an interview. The strongest predictor of HTLV-1/2 in case-control analysis was birth in a high-prevalence country (OR 39.8, 95% CI 7.8-204.3) but about 50% of HTLV-1 and 90% of HTLV-2 were Canadian-born. CONCLUSION: HTLV-1/2 prevalence is low in blood donors. High-prevalence country of birth accounts for about half of HTLV-1; HTLV-2 positives are usually Canadian-born. HTLV-1/2 transmission likely occurs overseas and within Canada.

RéSUMé: OBJECTIFS: Estimer la prévalence des sous-types du virus T-lymphotrope humain (HTLV-1 et HTLV-2) dans le sang des donneurs de sang canadiens, et évaluer le lien avec des variables démographiques et des facteurs de risque donnés. MéTHODES: Cette étude a porté sur toutes les personnes ayant fait leur premier don entre 1990 et 2022 au Canada, sauf au Québec. Les échantillons de sang ont été soumis à un test immunoenzymatique, puis à un test Western Blot de confirmation. Les données ont été analysées au moyen de la régression logistique en utilisant comme indices l'année, la tranche d'âge, le sexe, la région, le quartier, la privation matérielle et la composition ethnoculturelle. Depuis 2005, tous les donneurs positifs au HTLV-1/2 (cas) ont été conviés à un entretien ayant pour but de déterminer leurs facteurs de risque, et quatre donneurs négatifs (cas-témoins) ont été appariés à chaque cas en fonction de l'âge, du sexe et de la région. Les facteurs de prédiction d'infection au HTLV-1/2 des cas-témoins ont été analysés au moyen de la régression logistique. RéSULTATS: Entre 1990 et 2022, le nombre de primodonneurs s'élevait à 3 085 554. La prévalence du HTLV-1/2 est demeurée faible (12,2 sur 100 000 en 2022, IC 95%: 6,4­23,5). Le rapport de cotes était plus élevé chez les femmes (2,0, IC 95% 1,5­2,6), chez les personnes de plus de 50 ans (6,3, IC 95% 4,3­9,2), en Colombie-Britannique et en Ontario, chez les personnes touchées par la privation matérielle (1,9, IC 95% 1,2­2,9) et chez les personnes vivant dans des quartiers ethnoculturels (7,5, IC 95% 3,2­17,3). La plupart des cas de HTLV-1/2 rencontrés en Ontario concernaient le HTLV-1, tandis qu'en Colombie-Britannique, la moitié des cas concernait le HTLV-2. Quarante-trois cas sur 149 (28,8 %) et 172 cas-témoins sur 413 (41,6 %) ont passé l'entretien. L'analyse des cas-témoins a révélé que le facteur de prédiction le plus important d'infection au HTLV-1/2 était le fait d'être né dans un pays à forte prévalence (RC 39,8, IC 95% 7,8­204,3); toutefois environ 50 % des cas-témoins de HTLV-1 et 90 % des cas témoins de HTLV-2 étaient nés au Canada. CONCLUSION: La prévalence du HTLV-1/2 est faible dans le sang des donneurs de sang. Pays de naissance à forte prévalence représente à peu près la moitié des cas de HTLV-1; les donneurs positifs au HTLV-2 la plupart du temps sont nés au Canada. La transmission du HTLV-1/2 survient probablement outre-mer et au Canada.

SARS-CoV-2 vaccination in Canadian blood donors: Insight into donor representativeness of the general population.

Introduction: Blood donors world-wide were indispensable for monitoring anti-SARS-CoV-2 antibodies generated by infection and vaccination during the pandemic. Prior to the pandemic, donor vaccination behaviours were under-studied. We aimed to compare the percentage of Canadian blood donors with SARS-CoV-2 vaccination antibodies with the percentage of the general population who received at least one dose of vaccine each month during initial vaccine deployment. We also report donor attitudes towards SARS-CoV-2 vaccination. Methods: Canadian blood donors were randomly selected for SARS-CoV-2 antibody testing over 2021 (N = 165,240). The percentage of donor samples with vaccination antibodies were compared with the percentage of general population who received at least one dose of vaccine in each month of 2021 except February. A random sample of Canadian blood donors were surveyed about vaccination intent and attitudes (N = 4,558 participated, 30.4 % response rate). Results: The percentages of the general population vaccinated and donors with vaccination antibodies increased from 1 % to over 90 %. General population vaccination was greater early in vaccine deployment than donors (p < 0.05), greater in donors than the general population by mid-2021 (p < 0.05) but they were similar by the end of 2021. While 52.6 % of surveyed donors had received vaccine in May 2021, a further 41.1 % intended to when eligible. Most donors thought COVID-19 infection could be serious (83.5 %) and that it was important to be vaccinated even if previously infected (77.8 %). Conclusion: Early pandemic vaccine prioritization to at-risk individuals and healthcare workers gave rise to higher general population vaccination percentages, while donors had higher vaccine antibody percentages as vaccine was deployed to progressively younger age groups. Since blood donors may be more willing to receive vaccination, under pandemic conditions they may be valuable for monitoring vaccination-induced seroprevalence.

Data quality in healthcare: A report of practical experience with the Canadian Primary Care Sentinel Surveillance Network data.

Data quality (DQ) is the degree to which a given dataset meets a user's requirements. In the primary healthcare setting, poor quality data can lead to poor patient care, negatively affect the validity and reproducibility of research results and limit the value that such data may have for public health surveillance. To extract reliable and useful information from a large quantity of data and to make more effective and informed decisions, data should be as clean and free of errors as possible. Moreover, because DQ is defined within the context of different user requirements that often change, DQ should be considered to be an emergent construct. As such, we cannot expect that a sufficient level of DQ will last forever. Therefore, the quality of clinical data should be constantly assessed and reassessed in an iterative fashion to ensure that appropriate levels of quality are sustained in an acceptable and transparent manner. This document is based on our hands-on experiences dealing with DQ improvement for the Canadian Primary Care Sentinel Surveillance Network database. The DQ dimensions that are discussed here are accuracy and precision, completeness and comprehensiveness, consistency, timeliness, uniqueness, data cleaning and coherence.

Detecting Patients With Nonvalvular Atrial Fibrillation and Atrial Flutter in the Canadian Primary Care Sentinel Surveillance Network: First Steps.

BACKGROUND: A recent feasibility assessment of quality indicators for nonvalvular atrial fibrillation/atrial flutter (NVAF/AFL) identified the Canadian Primary Care Sentinel Surveillance Network, a national outpatient electronic medical record (EMR) system, as a data source for measurement. As a first step, we adapted and validated an existing EMR case definition. METHODS: A diagnosis of NVAF/AFL was defined using International Classification of Disease, 9th Revision, Clinical Modification codes (427.3) in either the physician billing, encounter diagnosis, or health condition fields. We identified all presumed cases in a single clinical site with the algorithm and selected a random sample of those who were presumed NVAF/AFL negative with the same algorithm. A chart audit diagnosis of "definite" NVAF/AFL was confirmed by electrocardiogram and nonvalvular diagnosis confirmed after echocardiogram, attending physician, or specialist letter review. To demonstrate face validity, clinical characteristics were compared for patients with and without NVAF/AFL. RESULTS: The case definition identified a possible 184 patients with and 184 without NVAF/AFL. The case validation resulted in a sensitivity of 100% (95% confidence interval [CI], 100-100), specificity of 84.3% (95% CI, 78.8-89.9), and positive and negative predictive value of 74.7% (95% CI, 66.4-83.2) and 100% (95% CI 100-100), respectively. Patients with NVAF/AFL were older (63 vs 42 years) and had a higher proportion of cardiovascular comorbidities and relevant medications. CONCLUSIONS: We think it is possible that with further validation work, NVAF/AFL can be accurately identified using this large pan-Canadian EMR system and used as a future tool to measure quality of care in the outpatient setting.

CONTEXTE: Dans le cadre d'une étude récente visant à déterminer s'il est possible d'utiliser des indicateurs de qualité pour évaluer les soins prodigués en cas de fibrillation auriculaire (FA) non valvulaire/flutter auriculaire, le Réseau canadien de surveillance sentinelle en soins primaires, un système national regroupant des données provenant des dossiers médicaux électroniques (DME) de patients vus en contexte de soins ambulatoires, a été retenu comme source de données pour une telle évaluation. Dans un premier temps, nous avons adapté et validé une définition de cas existante dans les DME. MÉTHODOLOGIE: On considérait qu'il y avait diagnostic de FA non valvulaire/flutter auriculaire si le code de la Classification internationale des maladies (9e révision, Modification clinique) correspondant (code 427.3) figurait dans un des champs de facturation des actes médicaux, des diagnostics de consultation ou des problèmes de santé du DME. Nous avons relevé tous les cas de FA non valvulaire/flutter auriculaire présumés d'une même clinique à l'aide de l'algorithme établi et constitué un échantillon aléatoire de patients qui, selon le même algorithme, ne présentaient pas de FA non valvulaire/flutter auriculaire. On a ensuite vérifié les dossiers pour confirmer le diagnostic; le cas de FA non valvulaire/flutter auriculaire était « certain ¼ si le dossier comprenait un électrocardiogramme positif et un diagnostic confirmé par échocardiographie, ou une note du médecin traitant ou d'un spécialiste confirmant le diagnostic. Pour démontrer la validité apparente de l'algorithme, les caractéristiques cliniques des patients atteints de FA non valvulaire/flutter auriculaire ont été comparées à celles des patients sans FA non valvulaire/flutter auriculaire. RÉSULTATS: La définition de cas a permis de repérer 184 patients ayant possiblement une FA non valvulaire/flutter auriculaire, et 184 autres patients sans FA non valvulaire/flutter auriculaire. À l'issue de la validation, la sensibilité de la définition de cas s'établissait à 100 % (intervalle de confiance [IC] à 95 % : 100 à 100), sa spécificité, à 84,3 % (IC à 95 % : 78,8 à 89,9), et ses valeurs prédictives positive et négative, à respectivement 74,7 % (IC à 95 % : 66,4 à 83,2) et 100 % (IC à 95 % : 100 à 100). Les patients atteints de FA non valvulaire/flutter auriculaire étaient plus âgés (63 vs 42 ans) et recevaient un traitement pour des affections cardiovasculaires concomitantes dans une plus forte proportion. CONCLUSIONS: Nous croyons qu'en approfondissant les travaux de validation, il serait possible de repérer avec précision les cas de FA non valvulaire/flutter auriculaire à partir des données de ce système pancanadien de surveillance des DME et de les utiliser pour évaluer la qualité des soins aux patients vus en contexte ambulatoire.

Mucopolysaccharidosis type II detection by Naïve Bayes Classifier: An example of patient classification for a rare disease using electronic medical records from the Canadian Primary Care Sentinel Surveillance Network.

Identifying patients with rare diseases associated with common symptoms is challenging. Hunter syndrome, or Mucopolysaccharidosis type II is a progressive rare disease caused by a deficiency in the activity of the lysosomal enzyme, iduronate 2-sulphatase. It is inherited in an X-linked manner resulting in males being significantly affected. Expression in females varies with the majority being unaffected although symptoms may emerge over time. We developed a Naïve Bayes classification (NBC) algorithm utilizing the clinical diagnosis and symptoms of patients contained within their de-identified and unstructured electronic medical records (EMR) extracted by the Canadian Primary Care Sentinel Surveillance Network (CPCSSN). To do so, we created a training dataset using published results in the scientific literature and from all MPS II symptoms and applied the training dataset and its independent features to compute the conditional posterior probabilities of having MPS II disease as a categorical dependent variable for 506497 male patients. The classifier identified 125 patients with the highest likelihood for having the disease and 18 features were selected to be necessary for forecasting. Next, a Recursive Backward Feature Elimination algorithm was employed, for optimal input features of the NBC model, using a k-fold Cross-Validation with 3 replicates. The accuracy of the final model was estimated by the Validation Set Approach technique and the bootstrap resampling. We also investigated that whether the NBC is as accurate as three other Bayesian networks. The Naïve Bayes Classifier appears to be an efficient algorithm in assisting physicians with the diagnosis of Hunter syndrome allowing optimal patient management.

Superoxide dismutase responses of strawberry cultivars to infection by Mycosphaerella fragariae.

In controlled conditions, the effect of leaf infection by Mycosphaerella fragariae on total superoxide dismutase (SOD, EC 1.15.1.1) activity and induction of SOD isozymes was studied in three different strawberry cultivars, i.e. "Joliette" (resistant), "Honeoye" (partially resistant) and "Kent" (susceptible). Infection of the strawberry leaves with M. fragariae resulted in increase in SOD activities in all three cv. Total SOD increased 1d after inoculation in Joliette and Kent, and 2d after inoculation in Honeoye and reached the highest level in all three cv, at the 2nd day after inoculation, then slowly declined afterward. Total SODs in Joliette and Honeoye at the 2nd day after inoculation were 4516 and 4947Ug(-1) FW, respectively, which were significantly higher than that of Kent (3255Ug(-1)FW). Banding pattern of SOD isozymes in all three cv was also affected by infection. Electrophoresis profile of infected cv revealed two newly synthesized isozymes in Joliette and Honeoye, in which one band, i.e. R(f) = 0.53 was observed exclusively in inoculated Joliette and Honeoye. Therefore, it is considered to be associated with leaf spot resistance.