Cerebral palsy in Canada, 2011-2031: results of a microsimulation modelling study of epidemiological and cost impacts. / La paralysie cérébrale au Canada, 2011-2031 : résultats d'une étude de modélisation par microsimulation des répercussions épidémiologiques et économiques.

INTRODUCTION: The objective of our study was to present model-based estimates and projections on current and future health and economic impacts of cerebral palsy in Canada over a 20-year time horizon (2011-2031). METHODS: We used Statistics Canada's Population Health Model (POHEM)-Neurological to simulate individuals' disease states, risk factors and health determinants and to describe and project health outcomes, including disease incidence, prevalence, life expectancy, health-adjusted life expectancy, health-related quality of life and health care costs over the life cycle of Canadians. Cerebral palsy cases were identified from British Columbia's health administrative data sources. A population-based cohort was then used to generate the incidence and mortality rates, enabling the projection of future incidence and mortality rates. A utility-based measure (Health Utilities Index Mark 3) was also included in the model to reflect various states of functional health to allow projections of health-related quality of life. Finally, we estimated caregiving parameters and health care costs from Canadian national surveys and health administrative data and included them as model parameters to assess the health and economic impact of cerebral palsy. RESULTS: Although the overall crude incidence rate of cerebral palsy is projected to remain stable, newly diagnosed cases of cerebral palsy will rise from approximately 1800 in 2011 to nearly 2200 in 2031. In addition, the number of people with the condition is expected to increase from more than 75 000 in 2011 to more than 94 000 in 2031. Direct health care costs in constant 2010 Canadian dollars were about $11 700 for children with cerebral palsy aged 1-4 years versus about $600 for those without the condition. In addition, people with cerebral palsy tend to have longer periods in poorer health-related quality of life. CONCLUSION: Individuals with cerebral palsy will continue to face challenges related to an ongoing need for specialized medical care and a rising need for supportive services. Our study offers important insights into future costs and impacts associated with cerebral palsy and provides valuable information that could be used to develop targeted health programs and strategies for Canadians living with this condition.

Trends in chronic disease incidence rates from the Canadian Chronic Disease Surveillance System. / Tendances des taux d'incidence des maladies chroniques d'après le Système canadien de surveillance des maladies chroniques.

INTRODUCTION: The Public Health Agency of Canada's Canadian Chronic Disease Surveillance System (CCDSS) produces population-based estimates of chronic disease prevalence and incidence using administrative health data. Our aim was to assess trends in incidence rates over time, trends are essential to understand changes in population risk and to inform policy development. METHODS: Incident cases of diagnosed asthma, chronic obstructive pulmonary disease (COPD), diabetes, hypertension, ischemic heart disease (IHD), and stroke were obtained from the CCDSS online infobase for 1999 to 2012. Trends in national and regional incidence estimates were tested using a negative binomial regression model with year as a linear predictor. Subsequently, models with year as a restricted cubic spline were used to test for departures from linearity using the likelihood ratio test. Age and sex were covariates in all models. RESULTS: Based on the models with year as a linear predictor, national incidence rates were estimated to have decreased over time for all diseases, except diabetes; regional incidence rates for most diseases and regions were also estimated to have decreased. However, likelihood ratio tests revealed statistically significant departures from a linear year effect for many diseases and regions, particularly for hypertension. CONCLUSION: Chronic disease incidence estimates based on CCDSS data are decreasing over time, but not at a constant rate. Further investigations are needed to assess if this decrease is associated with changes in health status, data quality, or physician practices. As well, population characteristics that may influence changing incidence trends also require exploration.

Type 1 diabetes incidence and prevalence trends in a cohort of Canadian children and youth.

BACKGROUND AND OBJECTIVE: Incidence rates of type 1 diabetes have long been on the rise across the globe, however, there is emerging evidence that the rate of rise may be slowing. The objective of this study was to describe trends in the incidence and prevalence of type 1 diabetes in a sample of Canadian children and youth. METHODS: Cases were extracted using linked administrative datasets and a validated diabetes case-finding definition. Incidence and prevalence trends were analyzed using the JoinPoint regression analysis program. RESULTS: A small increase in the incidence of type 1 diabetes was observed over the 11-year period from 2002-2003 to 2012-2013. Total incident cases per year ranged from 201 (2005-2006) to 250 (2007-2008). Total prevalent cases per year ranged from 1790 (2002-2003) to 2264 (2012-2013). Incidence was highest among children aged 5 to 14 years, and lowest in the youngest (1-4 years) and oldest (15-19 years) age brackets. The most significant increase in incidence was in children aged 10 to 14 years. Age-standardized prevalence increased significantly throughout the study period. CONCLUSION: These results are similar to data from the United States but differ from European data with respect to the annual percent change for incidence as well as age-specific incidence trends. In keeping with the low mortality rates associated with type 1 diabetes, the prevalence continues to rise.

The Canadian Chronic Disease Surveillance System: A model for collaborative surveillance.

Chronic diseases have a major impact on populations and healthcare systems worldwide. Administrative health data are an ideal resource for chronic disease surveillance because they are population-based and routinely collected. For multi-jurisdictional surveillance, a distributed model is advantageous because it does not require individual-level data to be shared across jurisdictional boundaries. Our objective is to describe the process, structure, benefits, and challenges of a distributed model for chronic disease surveillance across all Canadian provinces and territories (P/Ts) using linked administrative data. The Public Health Agency of Canada (PHAC) established the Canadian Chronic Disease Surveillance System (CCDSS) in 2009 to facilitate standardized, national estimates of chronic disease prevalence, incidence, and outcomes. The CCDSS primarily relies on linked health insurance registration files, physician billing claims, and hospital discharge abstracts. Standardized case definitions and common analytic protocols are applied to the data for each P/T; aggregate data are shared with PHAC and summarized for reports and open access data initiatives. Advantages of this distributed model include: it uses the rich data resources available in all P/Ts; it supports chronic disease surveillance capacity building in all P/Ts; and changes in surveillance methodology can be easily developed by PHAC and implemented by the P/Ts. However, there are challenges: heterogeneity in administrative databases across jurisdictions and changes in data quality over time threaten the production of standardized disease estimates; a limited set of databases are common to all P/Ts, which hinders potential CCDSS expansion; and there is a need to balance comprehensive reporting with P/T disclosure requirements to protect privacy. The CCDSS distributed model for chronic disease surveillance has been successfully implemented and sustained by PHAC and its P/T partners. Many lessons have been learned about national surveillance involving jurisdictions that are heterogeneous with respect to healthcare databases, expertise and analytical capacity, population characteristics, and priorities.

Incidence and prevalence trends of youth-onset type 2 diabetes in a cohort of Canadian youth: 2002-2013.

OBJECTIVE: Youth-onset type 2 diabetes is an emerging disease. We estimated incidence and prevalence trends of youth-onset type 2 diabetes between 2002 and 2013 in the Canadian province of British Columbia. METHODS: This population-based cohort study used a validated diabetes case-finding definition and algorithm to differentiate type 2 from type 1 diabetes to identify youth <20 years with type 2 diabetes within linked population-based administrative data. Age-standardized incidence and prevalence were calculated. JoinPoint regression and double exponential smooth modeling were used. RESULTS: From 2002/2003 to 2012/2013, the incidence of youth-onset type 2 diabetes increased from 3.45 (95% confidence interval, CI: 2.43, 4.80) to 5.16 (95% CI: 3.86, 6.78)/100 000. The annual percent change (APC) in incidence was 3.74 (95% CI: 1.61, 5.92; P = 0.003) overall, while it was 5.94 (95% CI: 1.84, 10.20; P = 0.009) and 0.53 (95% CI: -5.04, 6.43; P = 0.837) in females and males, respectively. The prevalence increased from 0.009% (95% CI: 0.007, 0.011) in 2002/2003 to 0.021% (95% CI: 0.018, 0.024) in 2012/2013 with an APC of 7.89 (95% CI: 6.41, 9.40; P < 0.0001). In females, it increased from 0.012% (95% CI: 0.009, 0.015) to 0.027% (95% CI: 0.023, 0.032) and in males from 0.007% (95% CI: 0.005, 0.009) to 0.015% (95% CI: 0.012, 0.019). By 2030, we forecast a prevalence of 0.046% (95% CI: 0.043, 0.048). CONCLUSIONS: Youth-onset type 2 diabetes is increasing with higher rates in females vs males. If these rates continue, in 2030, the number of cases will increase by 5-fold. These data are needed to set priorities for diabetes prevention in youth.

Estimating multimorbidity prevalence with the Canadian Chronic Disease Surveillance System. / Estimation de la prévalence de la multimorbidité au moyen du Système canadien de surveillance des maladies chroniques.

INTRODUCTION: The Public Health Agency of Canada's Canadian Chronic Disease Surveillance System (CCDSS) uses a validated, standardized methodology to estimate prevalence of individual chronic diseases, such as diabetes. Expansion of the CCDSS for surveillance of multimorbidity, the co-occurrence of two or more chronic diseases, could better inform health promotion and disease prevention. The objective of this study was to assess the feasibility of using the CCDSS to estimate multimorbidity prevalence. METHODS: We used administrative health data from seven provinces and three territories and five validated chronic conditions (i.e. cardiovascular disease, respiratory disease, mental illness, hypertension and diabetes) to estimate multimorbidity prevalence. We produced age-standardized (using Canada's 1991 population) and age-specific estimates for two multimorbidity definitions: (1) two or more conditions, and (2) three or more conditions from the five validated conditions, by sex, fiscal year and geography. RESULTS: Among Canadians aged 40 years and over in the fiscal year 2011/12, the prevalence of two or more and three or more chronic conditions was 26.5% and 10.2%, respectively, which is comparable to other estimates based on administrative health data. The increase in multimorbidity prevalence with increasing age was similar across provinces. The difference in prevalence for males and females varied by province and territory. We observed substantial variation in estimates over time. Results were consistent for the two definitions of multimorbidity. CONCLUSION: The CCDSS methodology can produce comparative estimates of multimorbidity prevalence across provinces and territories, but there are challenges in using it to estimate temporal trends. Further expansion of the CCDSS in the number and breadth of validated case definitions will improve the accuracy of multimorbidity surveillance for the Canadian population.

INTRODUCTION: Le Système canadien de surveillance des maladies chroniques (SCSMC) de l'Agence de la santé publique du Canada utilise une méthode validée et normalisée pour estimer la prévalence des maladies chroniques, par exemple le diabète. L'élargissement de la portée du SCSMC pour inclure la surveillance de la multimorbidité et de la présence concomitante de deux maladies chroniques ou plus pourrait mieux guider la promotion de la santé et la prévention des maladies. L'objectif de notre étude était de déterminer s'il était possible de recourir au SCSMC pour estimer la prévalence de la multimorbidité. MÉTHODOLOGIE: Nous avons utilisé les données administratives sur la santé de sept provinces et de trois territoires portant sur cinq affections chroniques validées (maladies cardiovasculaires, maladies respiratoires, maladies mentales, hypertension et diabète) pour estimer la prévalence de la multimorbidité. Nous avons produit des estimations normalisées selon l'âge et spécifiques selon l'âge (à l'aide des données démographiques canadiennes de 1991) pour deux définitions de la multimorbidité, soit deux affections ou plus ou trois affections ou plus sur les cinq affections validées, selon le sexe, la période et la zone géographique. RÉSULTATS: Au cours de l'exercice 2011-2012, la prévalence d'au moins deux et d'au moins trois affections chroniques chez les Canadiens de 40 ans ou plus se situait à respectivement 26,5 % et 10,2 %, ce qui est comparable à d'autres estimations faites à partir des données administratives sur la santé. L'augmentation de la prévalence de la multimorbidité avec l'âge était similaire dans toutes les provinces. Les différences de prévalence entre hommes et femmes variaient selon les provinces et territoires. Nous avons également observé une variation importante des estimations au fil des années. Les résultats obtenus étaient comparables pour les deux définitions de la multimorbidité. CONCLUSION: La méthodologie du SCSMC permet de produire des estimations comparatives de la prévalence de la multimorbidité dans l'ensemble des provinces et des territoires, mais son utilisation pour estimer les variations temporelles pose des difficultés. L'augmentation du nombre et de la portée des définitions de cas validées dans le SCSMC permettra d'améliorer l'exactitude de la surveillance de la multimorbidité auprès de la population canadienne.

Multiple sclerosis in Canada 2011 to 2031: results of a microsimulation modelling study of epidemiological and economic impacts. / La sclérose en plaques au Canada, 2011-2031 : résultats d'une étude de modélisation par microsimulation des répercussions épidémiologiques et économiques.

INTRODUCTION: The objective of our study was to present model-based estimates and projections on current and future health and economic impacts of multiple sclerosis (MS) in Canada over a 20-year time horizon (2011-2031). METHODS: Using Statistics Canada's Population Health Microsimulation Model (POHEM) framework, specifically the population-based longitudinal, microsimulation model named POHEM-Neurological, we identified people with MS from health administrative data sources and derived incidence and mortality rate parameters from a British Columbia population-based cohort for future MS incidence and mortality projections. We also included a utility-based measure (Health Utilities Index Mark 3) reflecting states of functional health to allow projections of health-related quality of life. Finally, we estimated caregiving parameters and health care costs from Canadian national surveys and health administrative data and included them as model parameters to assess the health and economic impact of the neurological conditions. RESULTS: The number of incident MS cases is expected to rise slightly from 4051 cases in 2011 to 4794 cases per 100 000 population in 2031, and the number of Canadians affected by MS will increase from 98 385 in 2011 to 133 635 in 2031. The total per capita health care cost (excluding out-of-pocket expenses) for adults aged 20 and older in 2011 was about $16 800 for individuals with MS, and approximately $2500 for individuals without a neurological condition. Thus, after accounting for additional expenditures due to MS (excluding out-of-pocket expenses), total annual health sector costs for MS are expected to reach $2.0 billion by 2031. As well, the average out-of-pocket expenditure for people with MS was around $1300 annually throughout the projection period. CONCLUSION: MS is associated with a significant economic burden on society, since it usually affects young adults during prime career- and family-building years. Canada has a particularly high prevalence of MS, so research such as the present study is essential to provide a better understanding of the current and future negative impacts of MS on the Canadian population, so that health care system policymakers can best plan how to meet the needs of patients who are affected by MS. These findings also suggest that identifying strategies to prevent MS and more effectively treat the disease are needed to mitigate these future impacts.

INTRODUCTION: L'objectif de notre étude est de présenter des estimations et des projections des répercussions épidémiologiques et économiques de la sclérose en plaques (SP) au Canada sur 20 ans (2011-2031). MÉTHODOLOGIE: Nous avons utilisé un modèle de microsimulation de la santé de la population (POHEM) de Statistique Canada, plus précisément le modèle longitudinal de microsimulation démographique appelé POHEM - Maladies neurologiques. Nous avons sélectionné les personnes atteintes de SP à partir de sources de données administratives sur la santé et dérivé les paramètres liés à l'incidence de la maladie et au taux de décès d'une étude de cohorte de la Colombie-Britannique afin de prévoir quels seront l'incidence de la SP et son taux de décès. Nous avons également inclus une mesure reposant sur l'utilité (Health Utilities Index Mark 3) qui rend compte des états de santé fonctionnelle afin de réaliser des projections sur la qualité de vie liée à la santé. Enfin, nous avons estimé les paramètres de prestation de soins et de coûts des soins de santé à partir de sondages nationaux du Canada et de données administratives sur la santé et nous les avons inclus comme paramètres dans le modèle visant à évaluer les répercussions économiques et sur la santé des maladies neurologiques. RÉSULTATS: On anticipe une légère augmentation du nombre de cas incidents de SP, passant de 4 051 cas pour 100 000 personnes en 2011 à 4 974 en 2031. Le nombre de Canadiens touchés par la SP passera ainsi de 98 385 en 2001 à 133 635 en 2031. Le coût total des soins de santé par personne (à l'exception des dépenses directes) pour les adultes de 20 ans et plus atteints de SP en 2011 était d'environ 16 800 $, contre un peu moins de 2500 $ pour ceux ne souffrant d'aucune affection neurologique. Si on comptabilise les dépenses supplémentaires liées à la SP (à l'exception des dépenses directes), les coûts totaux annuels de la SP pour le secteur de la santé devraient donc atteindre deux milliards de dollars d'ici 2031. Par ailleurs, les dépenses directes moyennes des personnes atteintes de SP seront d'environ 1300 $ par année tout au long de la période de projection. CONCLUSION: La SP est associée à un important fardeau économique pour la société car elle touche surtout de jeunes adultes à un moment fondateur pour leur vie professionnelle et leur vie familiale. Sa prévalence étant particulièrement élevée au Canada, des recherches comme la nôtre sont essentielles afin de mieux comprendre les répercussions actuelles et futures de la SP sur la population canadienne, afin que les décideurs du réseau de la santé puissent mieux planifier les besoins en soins de santé pour les malades qui en sont atteints. Selon ces résultats, des stratégies pour prévenir la SP et la traiter plus efficacement sont essentielles pour en atténuer les futures répercussions.

Alzheimer's and other dementias in Canada, 2011 to 2031: a microsimulation Population Health Modeling (POHEM) study of projected prevalence, health burden, health services, and caregiving use.

BACKGROUND: Worldwide, there is concern that increases in the prevalence of dementia will result in large demands for caregivers and supportive services that will be challenging to address. Previous dementia projections have either been simple extrapolations of prevalence or macrosimulations based on dementia incidence. METHODS: A population-based microsimulation model of Alzheimer's and related dementias (POHEM:Neurological) was created using Canadian demographic data, estimates of dementia incidence, health status (health-related quality of life and mortality risk), health care costs and informal caregiving use. Dementia prevalence and 12 other measures were projected to 2031. RESULTS: Between 2011 and 2031, there was a projected two-fold increase in the number of people living with dementia in Canada (1.6-fold increase in prevalence rate). By 2031, the projected informal (unpaid) caregiving for dementia in Canada was two billion hours per year, or 100 h per year per Canadian of working age. CONCLUSIONS: The projected increase in dementia prevalence was largely related to the expected increase in older Canadians, with projections sensitive to changes in the age of dementia onset.

Care delivery in youth with type 2 diabetes - are we meeting clinical practice guidelines?

BACKGROUND: Studies indicate high rates of treatment failure and early onset diabetes-related complications in youth-onset type 2 diabetes (T2D). We aim to describe the quality of care provided to children and youth with T2D. METHODS: This prospective cohort study used administrative datasets to describe individuals aged 10-24 yr diagnosed with T2D at <20 yr of age (488 individuals; 2111 person-years). The primary outcome was being 'at goal' for adherence to Canadian clinical practice guidelines (CPGs). This was defined as having either optimal [three diabetes-related physician visits/year, three hemoglobin A1C (A1C) tests/year, and all recommended screening tests for complications (i.e., retinopathy, nephropathy)] or good (two diabetes-related physician visits/year, two A1C tests/year, and at least two screening tests) adherence to CPGs. Descriptive statistics and logistic regression modeling were used. RESULTS: Sixty eight percentage person-years had poor adherence to CPGs (<2 physician visits and A1c tests/year and no screening tests). Only 29% and 25% were at goal for adherence in the 15-19 and 20-24 yr age groups, respectively. There was a 52% decreased odds of being at goal for adherence 4 yr after diagnosis of T2D (p < 0.001). For every year increase in age at diagnosis, there was a 5% decreased odds of being at goal (p = 0.04). CONCLUSIONS: Youth with T2D are not receiving high quality care, and older youth and young adults are particularly at risk. Future research is needed to understand the effectiveness of care in the context of poor adherence as well as patient, physician, and health system factors that might improve adherence.

Assessing the burden of hospitalized and community-care heart failure in Canada.

BACKGROUND: The surveillance of heart failure (HF) is currently conducted using either survey or hospital data, which have many limitations. Because Canada is collecting medical information in administrative health data, the present study seeks to propose methods for the national surveillance of HF using linked population-based data. METHODS: Linked administrative data from 5 Canadian provinces were analyzed to estimate prevalence, incidence, and mortality rates for persons with HF between 1996/1997 and 2008/2009 using 2 case definitions: (1) 1 hospitalization with an HF diagnosis in any field (H_Any) and (2) 1 hospitalization in any field or at least 2 physician claims within a 1-year period (H_Any_2P). One hospitalization with an HF diagnosis code in the most responsible diagnosis field (H_MR) was also compared. Rates were calculated for individuals aged ≥ 40 years. RESULTS: In 2008/2009, combining the 5 provinces (approximately 82% of Canada's total population), both age-standardized HF prevalence and incidence were underestimated by 39% and 33%, respectively, with H_Any when compared with H_Any_2P. Mortality was higher in patients with H_MR compared with H_Any. The degree of underestimation varied by province and by age, with older age groups presenting the largest differences. Prevalence estimates were stable over the years, especially for the H_Any_2P case definition. CONCLUSIONS: The prevalence and incidence of HF using inpatient data alone likely underestimates the population rates by at least 33%. The addition of physician claims data is likely to provide a more inclusive estimate of the burden of HF in Canada.

Surveillance of ischemic heart disease should include physician billing claims: population-based evidence from administrative health data across seven Canadian provinces.

BACKGROUND: Canadian provinces and territories routinely collect health information for administrative purposes. This study used Canadian medical and hospital administrative data for population-based surveillance of diagnosed ischemic heart disease (IHD). METHODS: Hospital discharge abstracts and physician billing claims data from seven provinces were analyzed to estimate prevalence and incidence of IHD using three validated algorithms: a) one hospital discharge abstract with an IHD diagnosis or procedure code (1H); b) 1H or at least three physician claims within a one-year period (1H3P) and c) 1H or at least two physician claims within a one-year period (1H2P). Crude and age-standardized prevalence and incidence rates were calculated for Canadian adults aged 20 +. RESULTS: IHD prevalence and incidence varied by province, were consistently higher among males than females, and increased with age. Prevalence and incidence were lower using the 1H method compared to using the 1H2P or 1H3P methods in all provinces studied for all age groups. For instance, in 2006/07, crude prevalence by province ranged from 3.4%-5.5% (1H), from 4.9%-7.7% (1H3P) and from 6.0%-9.2% (1H2P). Similarly, crude incidence by province ranged from 3.7-5.9 per 1,000 (1H), from 5.0-6.9 per 1,000 (1H3P) and from 6.1-7.9 per 1,000 (1H2P). CONCLUSIONS: Study findings show that incidence and prevalence of diagnosed IHD will be underestimated by as much as 50% using inpatient data alone. The addition of physician claims data are needed to better assess the burden of IHD in Canada.

Adherence to clinical practice guidelines in the management of children, youth, and young adults with type 1 diabetes--a prospective population cohort study.

OBJECTIVE: To describe adherence to clinical practice guidelines for the treatment of childhood type 1 diabetes and identify associated patient and system level factors. STUDY DESIGN: This prospective cohort study used population-based administrative data to describe individuals aged 1-24 years who had been diagnosed with type 1 diabetes at <20 years of age (1472 unique individuals and 5883 person-years over a 7-year period) living in British Columbia, Canada. The outcome measure was proportion 'at goal,' which was defined as having optimal adherence (3 diabetes-related physician visits/year, 3 hemoglobin A1c (HbA1c) tests/year, 1 glucagon prescription dispensed/year, and appropriate screening for diabetes-related comorbidity [ie, hypothyroidism] and complications [ie, retinopathy and nephropathy]), or good adherence to guidelines (2 diabetes-related physician visits/year, 2 HbA1c tests/year, and appropriate screening for diabetes-related comorbidity and complications). Statistical methods included descriptive statistics and logistic regression modeling. RESULTS: Fifty-four percent person-years had poor adherence to guidelines (<2 diabetes-related physician visits and HbA1c tests/year) and 7.4% had optimal adherence. The proportion of person-years at goal was higher in females vs males (41.0% vs 37.6%; P = .007). Individuals 4-years post-diagnosis of diabetes were 78% less likely to be at goal compared with the year of diagnosis (P < .0001). CONCLUSIONS: The treatment of pediatric type 1 diabetes likely does not meet national and international standards. Future studies should explore facilitators and barriers to adherence to guidelines among health care providers, patients, and families, and whether adherence to guidelines is associated with glycemic control.

Comparison of diagnosed, self-reported, and physically-measured hypertension in Canada.

BACKGROUND: Hypertension is a substantial health concern because it poses significant risks for cardiovascular morbidity and mortality and is highly prevalent in the population. Tracking hypertension is important because it is a risk factor for other conditions, but prevalence estimates might vary depending on the data source used. METHODS: This report describes 3 national population-based data sources for estimating hypertension prevalence in Canada and discusses their strengths and weaknesses to aid in their use for policy and program planning. They are compared based on: sample coverage, case identification, and prevalence estimates. RESULTS: Each source produces a different measure of hypertension prevalence, as follows: (1) diagnosed hypertension from the Canadian Chronic Disease Surveillance System (CCDSS) (2007/2008); (2) self-reported diagnosed hypertension from the Canadian Community Health Survey (CCHS) (2007-2008); and, (3) physically-measured hypertension from the Canadian Health Measures Survey (CHMS) (2007-2009). Crude rates and counts of hypertension prevalence among individuals aged 20 to 79 years of age, excluding pregnant women, are compared, resulting in prevalence ranging from 18.2% in self-report data to 20.3% in diagnosed data. The data sources differ in terms of target population, case identification, and limitations, which affects the estimates. CONCLUSIONS: Each source has unique strengths and is best suited for addressing particular research questions. For example, diagnosed hypertension can be used to determine health care utilization patterns, self-reported to examine health determinants, and measured high blood pressure to improve awareness, treatment, and control. Combined, they can address multiple issues and increase our knowledge of hypertension in Canada.

Validation of classification algorithms for childhood diabetes identified from administrative data.

OBJECTIVE: Type 1 diabetes is the most common form of diabetes among children; however, the proportion of cases of childhood type 2 diabetes is increasing. In Canada, the National Diabetes Surveillance System (NDSS) uses administrative health data to describe trends in the epidemiology of diabetes, but does not specify diabetes type. The objective of this study was to validate algorithms to classify diabetes type in children <20 yr identified using the NDSS methodology. PATIENTS AND METHODS: We applied the NDSS case definition to children living in British Columbia between 1 April 1996 and 31 March 2007. Through an iterative process, four potential classification algorithms were developed based on demographic characteristics and drug-utilization patterns. Each algorithm was then validated against a gold standard clinical database. RESULTS: Algorithms based primarily on an age rule (i.e., age <10 at diagnosis categorized type 1 diabetes) were most sensitive in the identification of type 1 diabetes; algorithms with restrictions on drug utilization (i.e., no prescriptions for insulin ± glucose monitoring strips categorized type 2 diabetes) were most sensitive for identifying type 2 diabetes. One algorithm was identified as having the optimal balance of sensitivity (Sn) and specificity (Sp) for the identification of both type 1 (Sn: 98.6%; Sp: 78.2%; PPV: 97.8%) and type 2 diabetes (Sn: 83.2%; Sp: 97.5%; PPV: 73.7%). CONCLUSIONS: Demographic characteristics in combination with drug-utilization patterns can be used to differentiate diabetes type among cases of pediatric diabetes identified within administrative health databases. Validation of similar algorithms in other regions is warranted.

Diagnosed hypertension in Canada: incidence, prevalence and associated mortality.

BACKGROUND: Hypertension is a leading risk factor for cardiovascular diseases. Our objectives were to examine the prevalence and incidence of diagnosed hypertension in Canada and compare mortality among people with and without diagnosed hypertension. METHODS: We obtained data from linked health administrative databases from each province and territory for adults aged 20 years and older. We used a validated case definition to identify people with hypertension diagnosed between 1998/99 and 2007/08. We excluded pregnant women from the analysis. RESULTS: This retrospective population-based study included more than 26 million people. In 2007/08, about 6 million adults (23.0%) were living with diagnosed hypertension and about 418,000 had a new diagnosis. The age-standardized prevalence increased significantly from 12.5% in 1998/99 to 19.6% in 2007/08, and the incidence decreased from 2.7 to 2.4 per 100. Among people aged 60 years and older, the prevalence was higher among women than among men, as was the incidence among people aged 75 years and older. The prevalence and incidence were highest in the Atlantic region. For all age groups, all-cause mortality was higher among adults with diagnosed hypertension than among those without diagnosed hypertension. INTERPRETATION: The overall prevalence of diagnosed hypertension in Canada from 1998 to 2008 was high and increasing, whereas the incidence declined during the same period. These findings highlight the need to continue monitoring the effectiveness of efforts for managing hypertension and to enhance public health programs aimed at preventing hypertension.