Estimating the completeness of physician billing claims for diabetes case ascertainment: a multiprovince investigation. / Estimation de l'exhaustivité des demandes de remboursement des médecins dans une optique de détermination des cas de diabète : étude menée dans plusieurs provinces.

INTRODUCTION: Previous research has suggested that how physicians are paid may affect the completeness of billing claims for estimating chronic disease. The purpose of this study is to estimate the completeness of physician billings for diabetes case ascertainment. METHODS: We used administrative data from eight Canadian provinces covering the period 1 April 2014 to 31 March 2016. The patient cohort was stratified into two mutually exclusive groups based on their physician remuneration type: fee-for-service (FFS), for those paid only on that basis; and non-fee-for-service (NFFS). Using diabetes prescription drug data as our reference data source, we evaluated whether completeness of disease case ascertainment varied with payment type. Diabetes incidence rates were then adjusted for completeness of ascertainment. RESULTS: The cohort comprised 86 110 patients. Overall, equal proportions received their diabetes medications from FFS and NFFS physicians. Overall, physician payment method had little impact upon the percentage of missed diabetes cases (FFS, 14.8%; NFFS, 12.2%). However, the difference in missed cases between FFS and NFFS varied widely by province, ranging from -1.0% in Nova Scotia to 29.9% in Newfoundland and Labrador. The difference between the observed and adjusted disease incidence rates also varied by province, ranging from 22% in Prince Edward Island to 4% in Nova Scotia. CONCLUSION: The difference in the loss of cases by physician remuneration method varied across jurisdictions. This loss may contribute to an underestimation of disease incidence. The method we used could be applied to other chronic diseases for which drug therapy could serve as reference data source.

Population coverage of the Canadian Chronic Disease Surveillance System: a survey of the contents of health insurance registries across Canada. / Couverture de la population dans le Système canadien de surveillance des maladies chroniques : enquête sur le contenu des registres d'assurance-maladie au Canada.

INTRODUCTION: Health insurance registries, which capture insurance coverage and demographic information for entire populations, are a critical component of population health surveillance and research when using administrative data. Lack of standardization of registry information across Canada's provinces and territories could affect the comparability of surveillance measures. We assessed the contents of health insurance registries across Canada to describe the populations covered and document registry similarities and differences. METHODS: A survey about the data and population identifiers in health insurance registries was developed by the study team and representatives from the Public Health Agency of Canada. The survey was completed by key informants from most provinces and territories and then descriptively analyzed. RESULTS: Responses were received from all provinces; partial responses were received from the Northwest Territories. Demographic information in health insurance registries, such as primary address, date of birth and sex, were captured in all jurisdictions. Data captured on familial relationships, ethnicity and socioeconomic status varied among jurisdictions, as did start and end dates of coverage and frequency of registry updates. Identifiers for specific populations, such as First Nations individuals, were captured in some, but not all jurisdictions. CONCLUSION: Health insurance registries are a rich source of information about the insured populations of the provinces and territories. However, data heterogeneity may affect who is included and excluded in population surveillance estimates produced using administrative health data. Development of a harmonized data framework could support timely and comparable population health research and surveillance results from multi-jurisdiction studies.

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.

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.

Impact of diabetes mellitus on life expectancy and health-adjusted life expectancy in Canada.

The objectives of this study were to estimate life expectancy (LE) and health-adjusted life expectancy (HALE) for Canadians with and without diabetes and to evaluate the impact of diabetes on population health using administrative and survey data.Mortality data from the Canadian Chronic Disease Surveillance System (2004 to 2006) and Health Utilities Index data from the Canadian Community Health Survey (2000 to 2005) were used. Life table analysis was applied to calculate LE, HALE, and their confidence intervals using the Chiang and the adapted Sullivan methods.LE and HALE were significantly lower among people with diabetes than for people without the disease. LE and HALE for females without diabetes were 85.0 and 73.3 years, respectively (males: 80.2 and 70.9 years). Diabetes was associated with a loss of LE and HALE of 6.0 years and 5.8 years, respectively, for females, and 5.0 years and 5.3 years, respectively, for males, living with diabetes at 55 years of age. The overall gains in LE and HALE after the hypothetical elimination of prevalent diagnosed diabetes cases in the population were 1.4 years and 1.2 years, respectively, for females, and 1.3 years for both LE and HALE for males.The results of the study confirm that diabetes is an important disease burden in Canada impacting the female and male populations differently. The methods can be used to calculate LE and HALE for other chronic conditions, providing useful information for public health researchers and policymakers.

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.

Health-Adjusted Life Expectancy among Canadian Adults with and without Hypertension.

Hypertension can lead to cardiovascular diseases and other chronic conditions. While the impact of hypertension on premature death and life expectancy has been published, the impact on health-adjusted life expectancy has not, and constitutes the research objective of this study. Health-adjusted life expectancy (HALE) is the number of expected years of life equivalent to years lived in full health. Data were obtained from the Canadian Chronic Disease Surveillance System (mortality data 2004-2006) and the Canadian Community Health Survey (Health Utilities Index data 2000-2005) for people with and without hypertension. Life table analysis was applied to calculate life expectancy and health-adjusted life expectancy and their confidence intervals. Our results show that for Canadians 20 years of age, without hypertension, life expectancy is 65.4 years and 61.0 years, for females and males, respectively. HALE is 55.0 years and 52.8 years for the two sexes at age 20; and 24.7 years and 22.9 years at age 55. For Canadians with hypertension, HALE is only 48.9 years and 47.1 years for the two sexes at age 20; and 22.7 years and 20.2 years at age 55. Hypertension is associated with a significant loss in health-adjusted life expectancy compared to life expectancy.

Women with multiple primary breast cancers diagnosed within a five year period, 1994-1998.

INTRODUCTION: Women diagnosed with a primary breast cancer are at higher risk for a second primary. Few studies have focused on a comparison of women with single breast primary cancers and women with multiple primary breast cancers. The 1994-1998 NAACCR dataset aggregated from high quality registries representing more than one-third of the US population provides a unique opportunity to examine the incidence of multiple primary breast cancers in a large population. MATERIALS AND METHODS: Using this multi-registry dataset, we describe the incidence pattern of malignant synchronous (within 2 months) and short-term metachronous (from 3 to 60 months) multiple primaries and single primary breast cancers by demographic and tumor characteristics. RESULTS: Synchronous multiple primary tumors were more similar in age, stage, and tumor grade to single breast tumors than they were to short-term metachronous tumors. The short-term metachronous tumors did not resemble either the synchronous tumors or the single primaries. DISCUSSION: These findings may indicate that while synchronous multiple primaries may have treatment implications different from single primaries, their etiology may be similar to single breast primaries. Further, they may actually be multi-centric single primaries. The two-month interval between multiple primaries is arbitrary and may not distinguish between the synchronous tumors and those occurring within 12 months of the index tumor. The rules for defining and counting breast primaries have implications for interpretation of incidence rates and temporal trends. These data also suggest the need for standard definitions for multiple primary breast tumors among clinicians, pathologists, and surveillance epidemiologists.