Prion disease risk perception in Canadian medical laboratories.

BACKGROUND: There are no national guidelines specific for handling prion-associated specimens in Canadian medical laboratories. Medical laboratory workers may perceive themselves at risk of prion transmission and, on occasion, decline to process such specimens. OBJECTIVE: To examine the knowledge, attitudes and reported behaviours of medical laboratory workers in relation to prion disease to understand their risk perception and the need for national laboratory guidelines on prion infection control. DESIGN: Survey development and cross-sectional web-based administration. METHODS: The survey was developed through key informant interviews and a modified Delphi process. Medical laboratory workers across Canada were invited by laboratory managers and national organizations to complete the web-based survey. RESULTS: Twelve key informant interviews were performed. Consensus for questionnaire content was reached through two rounds of the Delphi process. Responses were received from 426 Canadian medical laboratory workers; 37% of medical laboratory staff reported processing prion-associated specimens. Different protocols for specimen processing were followed, and 18% believed they were at risk when processing these specimens. Less than one-third of those receiving specimens believed they were adequately trained. The mean (±SD) knowledge score was 9.25±4.5/24; individuals who had received training scored significantly higher than those who were untrained (P<0.01). Eighty-one per cent of respondents would be more comfortable processing specimens if national guidelines existed and were used in their laboratory. CONCLUSION: There is a high perception of risk and few perceived benefits of processing prion-associated specimens. National guidelines for prion infection control in medical laboratories and adequate training would enable medical laboratory workers to process these specimens efficiently and confidently.

HISTORIQUE: Il n'existe pas de lignes directrices nationales propres à la manipulation d'échantillons associés aux infections à prion dans les laboratoires médicaux canadiens. Les travailleurs de ces laboratoires peuvent se percevoir comme vulnérables à la transmission d'une infection à prion et parfois refuser de traiter ces échantillons. OBJECTIF: Examiner les connaissances, les attitudes et les comportements déclarés des travailleurs de laboratoire pour comprendre leur perception du risque et la nécessité de préparer des lignes directrices nationales de laboratoire sur le contrôle des infections à prion. CONCEPTION: Élaboration de l'administration transversale d'un sondage par voie électronique. MÉTHODOLOGIE: Les chercheurs ont préparé le sondage par suite d'entrevues avec des informateurs clés et d'une méthode Delphi modifiée. Des directeurs de laboratoire et des organisations nationales ont invité les travailleurs de laboratoire du Canada à répondre au sondage par voie électronique. RÉSULTATS: Les chercheurs ont effectué 12 entrevues auprès d'informateurs clés. Ils sont parvenus à un consensus quant au contenu du questionnaire après deux rondes de la méthode Delphi. Ils ont reçu la réponse de 426 travailleurs de laboratoire canadiens, dont 37 % déclaraient traiter des échantillons liés à des infections à prion. Divers protocoles de traitement des échantillons étaient respectés, et 18 % des travailleurs se sentaient vulnérables dans le cadre de ce traitement. Moins du tiers des travailleurs qui recevaient ces échantillons se sentaient bien formés pour le faire. L'indice de connaissance moyen s'élevait à 9,25/24 (ÉT±4,5). Les personnes qui avaient reçu une formation obtenaient un indice considérablement plus élevé que celles qui n'en avaient pas reçu (P<0,01). Quatre-vingt-un pour cent des répondants seraient plus à l'aise de traiter les échantillons s'il existait des lignes directrices nationales mises en œuvre dans leur laboratoire. CONCLUSION: La perception du risque est élevée et celle des avantages du traitement des échantillons liés à des infections à prion est faible. Des lignes directrices nationales sur le contrôle des infections à prion dans les laboratoires médicaux et une formation convenable permettraient aux travailleurs de laboratoire de traiter ces échantillons avec efficacité et en toute confiance.

Using qualitative methods to investigate risk perception of Canadian medical laboratory workers in relation to current prion disease infection control policies.

The aim of this study was to determine the rationale, methodology, and progress of risk perceptions of laboratory workers in relation to existing prion disease infection control policies in Canadian medical laboratories. This study developed a Web survey that investigated the knowledge, behavior, and attitudes of laboratory staff in order to (1) identify strengths, weaknesses, and gaps of current prion infection prevention and control guidelines and (2) inform the development of national medical lab specific guidelines. The use of qualitative methods to develop a relevant survey is described and future research activities are outlined. Preliminary, qualitative data indicate that, among laboratory staff, there is a high degree of perceived susceptibility toward prion transmission in medical laboratories. Significant barriers to following existing prion infection control guidelines are reported with few benefits of following these guidelines. As a result, laboratories take precautions above those that are required when processing suspect prion-infected specimens, which may result in testing delays. A focused survey for laboratory staff that addresses these issues will provide insight on the necessary steps that will ensure safe and efficient diagnostic testing for suspect prion specimens.

A prospective cohort study of predictors of upper extremity arteriovenous fistula maturation.

BACKGROUND: A substantial proportion of arteriovenous fistulas fail to function adequately for hemodialysis. Existing studies on arteriovenous fistula failure prediction assess patency rather than the more clinically relevant outcome of arteriovenous fistula function. We hypothesized that preoperative demographic and ultrasound characteristics, and postoperative assessment by an experienced vascular access nurse would predict which arteriovenous fistulas will not function adequately for hemodialysis. METHODS: Prospective cohort study of chronic kidney disease patients at a tertiary care center in Vancouver, Canada, with arteriovenous fistula creation between 2009 and 2013. Pre and postoperative clinical assessment and ultrasound blood vessel mapping were performed by an experienced vascular access nurse. The primary outcome was failure to achieve a fistula used successfully for hemodialysis (FUSH). RESULTS: Outcomes were assessed in 200 patients; 123 (61.5%) arteriovenous fistulas were radiocephalic. Overall, 26.5% of arteriovenous fistulas had FUSH failure (34.1% of lower arm vs 14.3% of upper arm, p = 0.002). Univariate predictors of FUSH failure included older age (p = 0.03), female sex (p = 0.05), smaller arterial diameter (p ⩽ 0.001), lower artery volume flow (p = 0.04), and smaller vein diameter (p = 0.01). In multivariable analysis, artery diameter (odds ratio: 0.44, 95% confidence interval: 0.28-0.68) most significantly predicted FUSH failure. Vascular access nurse assessment 6 weeks postoperatively correctly predicted outcome in 83.8% of FUSH and 65.0% of FUSH failure. CONCLUSION: Smaller artery diameter most strongly predicted FUSH failure. Early postoperative nursing assessment was more useful to predict FUSH than FUSH failure, and as such was insufficient in determining which arteriovenous fistulas should be abandoned as many predicted to fail could be salvaged with further intervention.

Validation of Self-Reported Race in a Canadian Provincial Renal Administrative Database.

BACKGROUND: Administrative data are commonly used to study clinical outcomes in renal disease. Race is an important determinant of renal health delivery and outcomes in Canada but is not validated in most administrative data, and the correlation with census-based definitions of race is unknown. OBJECTIVES: Validation of self-reported race (SRR) in a Canadian provincial renal administrative database (Patient Records and Outcome Management Information System [PROMIS]) and comparison with the Canadian census categories of race. DESIGN: Prospective patient survey study to validate SRR in PROMIS. SETTING: British Columbia, Canada. PATIENTS: Adult patients registered in PROMIS. MEASUREMENTS: Survey SRR was used as gold standard to validate SRR in PROMIS. Self-reported race in PROMIS was compared with census race categories. METHODS: This is a cross-sectional telephone survey of a random sample of all adults in PROMIS conducted between February 2016 and November 2016. Responders selected a race category from PROMIS and from the Canadian census. Sensitivity (Sn) and specificity (Sp) were calculated with 95% confidence intervals (CIs). RESULTS: A total of 21 039 patients met inclusion criteria, 1677 were selected for the survey and 637 participated (38% response rate). There were no differences between the PROMIS, sampled, and responder populations. PROMIS SRR had an accuracy of 95.3% (95% CI: 94.2%-97.0%) when validated against the survey SRR with Sn and Sp ≥90% in all race groups except in Aboriginals (Sn 87.5%). The positive and negative predictive values were ≥95%, except in very low and high-prevalence groups, respectively. The Canadian census had an accuracy of 95.7% (95% CI: 94.4%-97.6%) when validated against PROMIS SRR with Sn and Sp ≥90%. The results did not differ in subgroups based on age, sex, birth outside Canada, or renal group (glomerulonephritis, chronic kidney disease, hemodialysis, peritoneal dialysis, transplant recipients, or live donors). LIMITATIONS: Analysis of minority groups and lower prevalence groups is limited by sample size. Results may not be generalizable to other administrative databases. CONCLUSIONS: We have shown high accuracy of PROMIS SRR that validates its use in the secondary analysis of administrative data for research. There is high correlation between PROMIS and census race categories which allows linkage with other data sources that use census-based definitions of race.

CONTEXTE: Les données administratives sont fréquemment utilisées pour étudier les issues cliniques en néphrologie. L'origine ethnique (OE) du patient est un déterminant important de la prestation de soins et des résultats en santé rénale au Canada, mais n'est pas validée dans la plupart des données administratives et la corrélation avec les définitions d'ethnies fondées sur le recensement demeure inconnue. OBJECTIFS: L'étude visait à valider l'origine ethnique autodéclarée (OEAD) dans une base de données administrative provinciale relative à la santé rénale (PROMIS), et à la comparer à l'origine ethnique inscrite au recensement canadien. TYPE D'ÉTUDE: Une étude prospective menée sous forme de sondage auprès de patients pour valider l'OEAD dans PROMIS. CADRE: Colombie-Britannique, Canada. SUJETS: Des patients adultes inscrits dans PROMIS. MESURES: L'OE mentionnée dans le sondage a servi d'étalon-or pour valider l'OEAD dans PROMIS, et cette dernière a été comparée à l'OE rapportée par le recensement. MÉTHODOLOGIE: Une enquête transversale conduite par téléphone entre février et novembre 2016 auprès d'un échantillon aléatoire d'adultes inscrits dans PROMIS. Les répondants devaient choisir une OE dans PROMIS et dans les catégories du recensement canadien. La sensibilité (Sn) et la spécificité (Sp) ont été calculées avec un intervalle de confiance à 95 % (IC 95 %). RÉSULTATS: Des 21 039 patients qui satisfaisaient les critères d'inclusion, 1 677 ont été sélectionnés pour le sondage et 637 ont participé (taux de réponse: 38 %). Aucune différence n'a été observée entre les populations de PROMIS, de l'échantillon et de répondants. L'OEAD dans PROMIS était exacte dans 95,3 % des cas (IC 95 %: 94,2-97,0 %), lorsque validée contre l'OEAD dans le sondage, avec une Sn et une Sp d'au moins 90 % pour tous les groupes ethniques, à l'exception des Autochtones (Sn: 87,5 %). Les valeurs prédictives positive et négative étaient d'au moins 95 %, sauf dans les groupes à très faible et à forte prévalence, respectivement. Le recensement canadien a montré une précision de 95,7 % (IC 95 %: 94,4-97,6 %) lorsque validé contre l'OEAD dans PROMIS avec une Sn et une Sp d'au moins 90 %. Les résultats n'ont pas varié dans les sous-groupes selon l'âge, le sexe, la naissance hors Canada ou le groupe de néphrologie (glomérulonéphrite, insuffisance rénale chronique, hémodialyse, dialyse péritonéale, receveurs d'une greffe ou donneurs vivants). LIMITES: L'analyse des groupes minoritaires et des groupes à faible prévalence est limitée par la taille de l'échantillon. Les résultats pourraient ne pas être généralisables à d'autres bases de données administratives. CONCLUSION: Nous avons montré la grande précision de l'OEAD dans PROMIS, ce qui valide son utilisation pour l'analyse secondaire de données administratives à des fins de recherche. Une forte corrélation existe entre les définitions de l'OE dans PROMIS et le recensement, ce qui permet d'établir des liens avec d'autres sources de données qui utilisent les mêmes définitions que le recensement.

Myocardial perfusion pressure in patients with hypertension and coronary artery disease: implications for DBP targets in hypertension management.

BACKGROUND: The target blood pressure (BP) in patients with hypertension and coronary artery disease (CAD) has been controversial. Whether patients with both diabetes mellitus and CAD should follow targets for either diabetes mellitus or CAD is uncertain. Focusing only on one determinant of coronary blood flow (CBF) - myocardial perfusion pressure (MPP) - coronary BP in patients with hypertension was used to estimate the impact of setting BP targets. METHODS: A consecutive series of 101 patients referred for coronary angiography for stable angina pectoris or possible CAD had BP measurements proximal and distal to coronary artery stenosis. Fractional flow reserve (FFR) was measured from adenosine-induced maximal hyperemia. DBP after the coronary stenosis was the MPP. The most severe coronary lesion for each person was selected. RESULTS: Of 101 patients, 65.0 ±â€Š10.6 years (mean ±â€ŠSD), there were 69 with hypertension and 33 with diabetes mellitus of whom 25 had diabetes mellitus along with hypertension. In hypertension, FFR was 0.83 ±â€Š0.08, range from 0.49 to 0.97, with 40% having FFR less than 0.8. There was a significant linear relationship between systemic DBP and MPP. CBF approximates zero with MMP of 50  mmHg under resting conditions and 40  mmHg with coronary vasodilatation. On the basis of our findings in hypertension, if DBP were 80, 70, 65 and 60  mmHg, 1.4, 7.1, 15.7 and 54.3%, respectively, of patients would have an MPP of less than 50  mmHg. The values were similar for patients with diabetes mellitus. CONCLUSION: In our patient group with moderate coronary artery stenosis, a target DBP of 60  mmHg or less would be associated with unacceptably low MPPs. In patients with diabetes mellitus, the presence and severity of CAD stenosis may be more important factor in setting BP targets for treatment of hypertension. Because the degree of coronary stenosis is unknown in most patients with hypertension and CAD, guideline recommendations should consider cautioning clinicians about the potential for myocardial ischaemia at low DBP.