Association between hypnotics use and increased mortality: causation or confounding?

PURPOSE: Many research studies have found associations between benzodiazepines and/or z-hypnotics (BZZ) and increasing mortality, leading to a discussion about causation or confounding. This study suggests a factor that could produce this association through confounding. METHODS: The Norwegian population in 2010 supplied 8862 deaths ages 41-80 and 898,289 controls. Index dates were added to control records which corresponded to death dates. BZZ use was recorded for 2 years before death/index date. RESULTS: Persons exposed to BZZ were more likely (OR = 2.3) to die than those who were not. With proximity of death, increasingly larger proportions of the prospective deaths received prescriptions for BZZ, until in the last 2 months 40-45% received BZZ. The frequency of BZZ use in controls increased with age as opposed to the death cohort where all ages showed similar rates of BZZ use. In the last few months before death, the youngest age group had an OR = 5.8 for BZZ use while the oldest age group an OR = 1.8, adjusted for age and sex. Opioid use showed a similar pattern of increasing use near death. CONCLUSIONS: The increased use of BZZ with approaching death is consistent with increasing symptomatic treatment in terminal illness. Thus, the association of BZZ and mortality is more likely to be due to confounding than to causality. Further evidence from this and other research includes similar use patterns for other drugs such as opioids, the lack of specificity in cause of death and the size of the association regarding age and time to death.

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.

Implementation of ICD-10 in Canada: how has it impacted coded hospital discharge data?

BACKGROUND: The purpose of this study was to assess whether or not the change in coding classification had an impact on diagnosis and comorbidity coding in hospital discharge data across Canadian provinces. METHODS: This study examined eight years (fiscal years 1998 to 2005) of hospital records from the Hospital Person-Oriented Information database (HPOI) derived from the Canadian national Discharge Abstract Database. The average number of coded diagnoses per hospital visit was examined from 1998 to 2005 for provinces that switched from International Classifications of Disease 9(th) version (ICD-9-CM) to ICD-10-CA during this period. The average numbers of type 2 and 3 diagnoses were also described. The prevalence of the Charlson comorbidities and distribution of the Charlson score one year before and one year after ICD-10 implementation for each of the 9 provinces was examined. The prevalence of at least one of the seventeen Charlson comorbidities one year before and one year after ICD-10 implementation were described by hospital characteristics (teaching/non-teaching, urban/rural, volume of patients). RESULTS: Nine Canadian provinces switched from ICD-9-CM to ICD-I0-CA over a 6 year period starting in 2001. The average number of diagnoses coded per hospital visit for all code types over the study period was 2.58. After implementation of ICD-10-CA a decrease in the number of diagnoses coded was found in four provinces whereas the number of diagnoses coded in the other five provinces remained similar. The prevalence of at least one of the seventeen Charlson conditions remained relatively stable after ICD-10 was implemented, as did the distribution of the Charlson score. When stratified by hospital characteristics, the prevalence of at least one Charlson condition decreased after ICD-10-CA implementation, particularly for low volume hospitals. CONCLUSION: In conclusion, implementation of ICD-10-CA in Canadian provinces did not substantially change coding practices, but there was some coding variation in the average number of diagnoses per hospital visit across provinces.

Cardiovascular outcomes after a change in prescription policy for clopidogrel.

BACKGROUND: Drug-reimbursement policies may have an adverse effect on patient outcomes if they interfere with timely access to efficacious medications for acute medical conditions. Clopidogrel in combination with aspirin is the recommended standard of care for patients receiving coronary stents to prevent thrombosis. We examined the population-level effect of a change by a Canadian provincial government in a pharmacy-benefits program from a prior-authorization policy to a less restrictive, limited-use policy on access to clopidogrel among patients undergoing percutaneous coronary intervention (PCI) with stenting after acute myocardial infarction. METHODS: We conducted a population-based, retrospective, time-series analysis from April 1, 2000, to March 31, 2005, of all patients 65 years of age or older with acute myocardial infarction who underwent PCI with stenting in Ontario, Canada. The primary outcome was the composite rate of death, recurrent acute myocardial infarction, PCI, and coronary-artery bypass grafting at 1 year, with adjustment for sex and age. The secondary outcome was major bleeding. RESULTS: The rate of clopidogrel use within 30 days after hospital discharge following myocardial infarction increased from 35% in the prior-authorization period to 88% in the limited-use period. The median time to the first dispensing of a clopidogrel prescription decreased from 9 days in the first period to 0 days in the second period. The 1-year composite cardiovascular outcome significantly decreased from 15% in the prior-authorization group to 11% in the limited-use group (P=0.02). Rates of bleeding in the two groups did not change. CONCLUSIONS: The removal of a prior-authorization program led to improvement in timely access to clopidogrel for coronary stenting and improved cardiovascular outcomes.

Changes in the rates of awareness, treatment and control of hypertension in Canada over the past two decades.

BACKGROUND: Analyses of medication databases indicate marked increases in prescribing of antihypertensive drugs in Canada over the past decade. This study was done to examine the trends in the prevalence of hypertension and in control rates in Canada between 1992 and 2009. METHODS: Three population-based surveys, the 1986-1992 Canadian Heart Health Surveys, the 2006 Ontario Survey on the Prevalence and Control of Hypertension and the 2007-2009 Canadian Health Measures Survey, collected self-reported health information from, and measured blood pressure among, community-dwelling adults. RESULTS: The population prevalence of hypertension was stable between 1992 and 2009 at 19.7%-21.6%. Hypertension control improved from 13.2% (95% confidence interval [CI] 10.7%-15.7%) in 1992 to 64.6% (95% CI 60.0%-69.2%) in 2009, reflecting improvements in awareness (from 56.9% [95% CI 53.1%-60.5%] in 1992 to 82.5% [95% CI 78.5%-86.0%] in 2009) and treatment (from 34.6% [95% CI 29.2%-40.0%] in 1992 to 79.0% [95% CI 71.3%-86.7%] in 2009) among people with hypertension. The size of improvements in awareness, treatment and control were similar among people who had or did not have cardiovascular comorbidities Although systolic blood pressures among patients with untreated hypertension were similar between 1992 and 2009 (ranging from 146 [95% CI 145-147] mm Hg to 148 [95% CI 144-151] mm Hg), people who did not have hypertension and patients with hypertension that was being treated showed substantially lower systolic pressures in 2009 than in 1992 (113 [95% CI 112-114] v. 117 [95% CI 117-117] mm Hg and 128 [95% CI 126-130] v. 145 [95% CI 143-147] mm Hg). INTERPRETATION: The prevalence of hypertension has remained stable among community-dwelling adults in Canada over the past two decades, but the rates for treatment and control of hypertension have improved markedly during this time.

In-hospital mortality in 13,263 survivors of out-of-hospital cardiac arrest in Canada.

BACKGROUND: There is a substantial mortality rate in patients admitted alive after out-of-hospital cardiac arrest. The primary objective of our study was to examine trends in in-hospital survival in out-of-hospital cardiac arrest survivors in Canada between 1994 and 2004. The secondary objective was to examine predictors of in-hospital survival in these patients. METHODS: Data on hospital admissions from April 1, 1994, to March 31, 2004, were obtained from the Health Person-oriented Information Database, maintained by Statistics Canada. We included all patients with a primary diagnosis of cardiac arrest who survived to hospital admission. We assessed survival to hospital discharge in all patients admitted alive. RESULTS: In Canada, 13,263 patients survived community arrest between 1994 and 2004. The annual incidence of hospital admission after out-of-hospital cardiac arrest decreased by 33%, from 5.37 per 100,000 in 1994 to 3.63 per 100,000 in 2004 (P < .0001 for trend). Subsequently, 5,045 patients (38.03%) survived to hospital discharge. The survival rate did not change during the duration of the study. Invasive coronary artery disease management was associated with a greatly increased chance of survival (odds ratio 21.98, 95% CI 17.62-27.42). Also male gender, heart failure, and acute myocardial ischemia were independent positive predictors of survival to hospital discharge; greater age and comorbidities were negative predictors of survival. Finally, there were significant interprovincial variations in survival rates. CONCLUSIONS: Our study, the largest of its kind, has 4 main findings. Firstly, between 1993 and 2004, there was a significant and steady decline in admission rates after community cardiac arrest. Second, there was no change in the in-hospital survival rates. Thirdly, invasive management of coronary artery disease was associated with a greatly improved chance of survival, and finally, there were important regional variations in survival rates.

National trends in rates of death and hospital admissions related to acute myocardial infarction, heart failure and stroke, 1994-2004.

BACKGROUND: Rates of death from cardiovascular and cerebrovascular diseases have been steadily declining over the past few decades. Whether such declines are occurring to a similar degree for common disorders such as acute myocardial infarction, heart failure and stroke is uncertain. We examined recent national trends in mortality and rates of hospital admission for these 3 conditions. METHODS: We analyzed mortality data from Statistic Canada's Canadian Mortality Database and data on hospital admissions from the Canadian Institute for Health Information's Hospital Morbidity Database for the period 1994-2004. We determined age- and sex-standardized rates of death and hospital admissions per 100,000 population aged 20 years and over as well as in-hospital case-fatality rates. RESULTS: The overall age- and sex-standardized rate of death from cardiovascular disease in Canada declined 30.0%, from 360.6 per 100,000 in 1994 to 252.5 per 100 000 in 2004. During the same period, the rate fell 38.1% for acute myocardial infarction, 23.5% for heart failure and 28.2% for stroke, with improvements observed across most age and sex groups. The age- and sex-standardized rate of hospital admissions decreased 27.6% for stroke and 27.2% for heart failure. The rate for acute myocardial infarction fell only 9.2%. In contrast, the relative decline in the in-hospital case-fatality rate was greatest for acute myocardial infarction (33.1%; p < 0.001). Much smaller relative improvements in case-fatality rates were noted for heart failure (8.1%) and stroke (8.9%). INTERPRETATION: The rates of death and hospital admissions for acute myocardial infarction, heart failure and stroke in Canada changed at different rates over the 10-year study period. Awareness of these trends may guide future efforts for health promotion and health care planning and help to determine priorities for research and treatment.

Long-term trends in use of and expenditures for cardiovascular medications in Canada.

BACKGROUND: Medication expenditures have become the fastest growing sector of costs within the Canadian health care system. Evaluation of the use of cardiovascular medications is important to determine the magnitude of the growth, to identify which medications dominate the landscape and to detect interprovincial differences in utilization. We describe long-term trends in the use of and expenditures for cardiovascular medications in Canada, by drug class and by province. METHODS: For these analyses, we used volume and expenditure data related to prescriptions for cardiovascular medications obtained from IMS Health Canada's CompuScript Audit database for the period 1996-2006. Here, we describe national and provincial patterns of utilization and expenditures for specified classes of cardiovascular medications. RESULTS: The use of cardiovascular medications increased sharply in Canada during the study period, with related costs rising by over 200% during this period to surpass $5 billion in 2006. Changes in population demographics, risk factors and inflation appeared to account for about two-thirds of the observed growth in expenditures. Use of newer medication classes (statins, angiotensin-receptor blockers, angiotensin-converting-enzyme inhibitors), for which patented brand name medications predominate, accounted for almost one-third of the cost increases. Interprovincial differences in total expenditures for cardiovascular drugs portrayed a descending gradient from east to west, with greatest variability for the newer drug classes. INTERPRETATION: Prescriptions and expenditures for cardiovascular medications in Canada escalated over the study period. Projected increases may reach potentially unsustainable levels. Greater emphasis on the use of cost-effective medications is required to limit further increases. Factors influencing interprovincial differences warrant further study.

The effect of universal influenza immunization on mortality and health care use.

BACKGROUND: In 2000, Ontario, Canada, initiated a universal influenza immunization program (UIIP) to provide free influenza vaccines for the entire population aged 6 mo or older. Influenza immunization increased more rapidly in younger age groups in Ontario compared to other Canadian provinces, which all maintained targeted immunization programs. We evaluated the effect of Ontario's UIIP on influenza-associated mortality, hospitalizations, emergency department (ED) use, and visits to doctors' offices. METHODS AND FINDINGS: Mortality and hospitalization data from 1997 to 2004 for all ten Canadian provinces were obtained from national datasets. Physician billing claims for visits to EDs and doctors' offices were obtained from provincial administrative datasets for four provinces with comprehensive data. Since outcomes coded as influenza are known to underestimate the true burden of influenza, we studied more broadly defined conditions. Hospitalizations, ED use, doctors' office visits for pneumonia and influenza, and all-cause mortality from 1997 to 2004 were modelled using Poisson regression, controlling for age, sex, province, influenza surveillance data, and temporal trends, and used to estimate the expected baseline outcome rates in the absence of influenza activity. The primary outcome was then defined as influenza-associated events, or the difference between the observed events and the expected baseline events. Changes in influenza-associated outcome rates before and after UIIP introduction in Ontario were compared to the corresponding changes in other provinces. After UIIP introduction, influenza-associated mortality decreased more in Ontario (relative rate [RR] = 0.26) than in other provinces (RR = 0.43) (ratio of RRs = 0.61, p = 0.002). Similar differences between Ontario and other provinces were observed for influenza-associated hospitalizations (RR = 0.25 versus 0.44, ratio of RRs = 0.58, p < 0.001), ED use (RR = 0.31 versus 0.69, ratio of RRs = 0.45, p < 0.001), and doctors' office visits (RR = 0.21 versus 0.52, ratio of RRs = 0.41, p < 0.001). Sensitivity analyses were carried out to assess consistency, specificity, and the presence of a dose-response relationship. Limitations of this study include the ecological study design, the nonspecific outcomes, difficulty in modeling baseline events, data quality and availability, and the inability to control for potentially important confounders. CONCLUSIONS: Compared to targeted programs in other provinces, introduction of universal vaccination in Ontario in 2000 was associated with relative reductions in influenza-associated mortality and health care use. The results of this large-scale natural experiment suggest that universal vaccination may be an effective public health measure for reducing the annual burden of influenza.

Comparison of provincial prescription drug plans and the impact on patients' annual drug expenditures.

BACKGROUND: Reimbursement for outpatient prescription drugs is not mandated by the Canada Health Act or any other federal legislation. Provincial governments independently establish reimbursement plans. We sought to describe variations in publicly funded provincial drug plans across Canada and to examine the impact of this variation on patients' annual expenditures. METHODS: We collected information, accurate to December 2006, about publicly funded prescription drug plans from all 10 Canadian provinces. Using clinical scenarios, we calculated the impact of provincial cost-sharing strategies on individual annual drug expenditures for 3 categories of patients with different levels of income and 2 levels of annual prescription burden ($260 and $1000). RESULTS: We found that eligibility criteria and cost-sharing details of the publicly funded prescription drug plans differed markedly across Canada, as did the personal financial burden due to prescription drug costs. Seniors pay 35% or less of their prescription costs in 2 provinces, but elsewhere they may pay as much as 100%. With few exceptions, nonseniors pay more than 35% of their prescription costs in every province. Most social assistance recipients pay 35% or less of their prescription costs in 5 provinces and pay no costs in the other 5. In an example of a patient with congestive heart failure, his out-of-pocket costs for a prescription burden of $1283 varied between $74 and $1332 across the provinces. INTERPRETATION: Considerable interprovincial variation in publicly funded prescription drug plans results in substantial variation in annual expenditures by Canadians with identical prescription burdens. A revised pharmaceutical strategy might reduce these major inequities.

Improvement in stroke mortality in Canada and the United States, 1990 to 2002.

BACKGROUND: In the United States and Canada, folic acid fortification of enriched grain products was fully implemented by 1998. The resulting population-wide reduction in blood homocysteine concentrations might be expected to reduce stroke mortality if high homocysteine levels are an independent risk factor for stroke. METHODS AND RESULTS: In this population-based cohort study with quasi-experimental intervention, we used segmented log-linear regression to evaluate trends in stroke-related mortality before and after folic acid fortification in the United States and Canada and, as a comparison, during the same period in England and Wales, where fortification is not required. Average blood folate concentrations increased and homocysteine concentrations decreased in the United States after fortification. The ongoing decline in stroke mortality observed in the United States between 1990 and 1997 accelerated in 1998 to 2002 in nearly all population strata, with an overall change from -0.3% (95% CI, -0.7 to 0.08) to -2.9 (95% CI, -3.5 to -2.3) per year (P=0.0005). Sensitivity analyses indicate that changes in other major recognized risk factors are unlikely to account for the reduced number of stroke-related deaths in the United States. The fall in stroke mortality in Canada averaged -1.0% (95% CI, -1.4 to -0.6) per year from 1990 to 1997 and accelerated to -5.4% (95% CI, -6.0 to -4.7) per year in 1998 to 2002 (P< or =0.0001). In contrast, the decline in stroke mortality in England and Wales did not change significantly between 1990 and 2002. CONCLUSIONS: The improvement in stroke mortality observed after folic acid fortification in the United States and Canada but not in England and Wales is consistent with the hypothesis that folic acid fortification helps to reduce deaths from stroke.

Use of implantable cardioverter defibrillators in Canadian and US survivors of out-of-hospital cardiac arrest.

BACKGROUND: Cardiac arrest due to ventricular arrhythmia in the absence of a reversible cause or contraindication has been a class I indication for insertion of an implantable cardioverter defibrillator since 1998. We compared and contrasted the use of implantable cardioverter defibrillator therapy in Canada and the United States among adults who survived a cardiac arrest. METHOD: Data on hospital separations from April 1, 1994 through March 31, 2003 were obtained from the Health Person-Oriented Information Database maintained by Statistics Canada and from the US National Hospital Discharge Survey on all patients with a primary diagnosis of cardiac arrest, ventricular fibrillation or ventricular flutter for the same 9-year period. We excluded all records of patients with a secondary diagnosis of acute myocardial infarction. RESULTS: In Canada, 3793 patients survived to discharge after a cardiac arrest; 628 (16.6%) of these were implanted with a cardioverter defibrillator before discharge. The implant rate rose steadily from 5.4% in 1994/95 to 26.7% in 2002/03. In the United States, 23 688 (30.2%) of 78 538 such survivors received an implantable cardioverter defibrillator before discharge. Logistic regression analysis indicated that sex, age, fiscal year, the hospital's teaching status, hospital size and patient history of heart failure were positive predictors of implantable cardioverter defibrillator implantation. Age, renal failure, liver failure and cancer were negative predictors of receiving an implantable cardioverter defibrillator. INTERPRETATION: The rate of use of implantable cardioverter defibrillator therapy for cardiac arrest survivors in Canada is increasing, but still is lower than the rate in the United States.

Incidence, comorbidity, case fatality and readmission of hospitalized stroke patients in Canada.

BACKGROUND: Stroke is a leading cause of death and disability, and poses a significant burden of care for those who survive. OBJECTIVES: To estimate the incidence of hospitalization for stroke and describe the impact of age, sex and comorbidity on in-hospital mortality, length of stay and readmission rates. METHODS: Health insurance numbers were used to link acute care hospitalizations across Canada in 1999/2000 for stroke patients with no discharges for a stroke within the preceding five years. Patients were followed up for one year from the date of their initial admission. RESULTS: The numbers of men (15,367) and women (16,740) in the study were similar. The incidence of all types of stroke (International Classification of Diseases, ninth revision, codes 430, 431 and 434/436) for hospitalized men and women was 14.4 per 10,000, with a 15-fold rise from 8.7 for the age group of 45 to 64 years to 131.9 per 10,000 for the age group 80 years and older. For the index episode, stroke patients spent an average of 21.0 days in the hospital, and 18.2% died in the hospital within 28 days. Of those who survived the first episode, 10.3% were readmitted to the hospital within one year with a recurrent stroke, and overall 37.1% were readmitted for any cause (including stroke). Among these stroke patients, hypertension was codiagnosed in 35%; diabetes in 17%; arrhythmia in 15%; ischemic heart disease in 13.6%; and congestive heart failure in 5%. CONCLUSIONS: Hospital records linked by patient identification can produce more accurate national estimates of patients hospitalized with stroke than any current countrywide surveillance system.

Identifying priorities in methodological research using ICD-9-CM and ICD-10 administrative data: report from an international consortium.

BACKGROUND: Health administrative data are frequently used for health services and population health research. Comparative research using these data has been facilitated by the use of a standard system for coding diagnoses, the International Classification of Diseases (ICD). Research using the data must deal with data quality and validity limitations which arise because the data are not created for research purposes. This paper presents a list of high-priority methodological areas for researchers using health administrative data. METHODS: A group of researchers and users of health administrative data from Canada, the United States, Switzerland, Australia, China and the United Kingdom came together in June 2005 in Banff, Canada to discuss and identify high-priority methodological research areas. The generation of ideas for research focussed not only on matters relating to the use of administrative data in health services and population health research, but also on the challenges created in transitioning from ICD-9 to ICD-10. After the brain-storming session, voting took place to rank-order the suggested projects. Participants were asked to rate the importance of each project from 1 (low priority) to 10 (high priority). Average ranks were computed to prioritise the projects. RESULTS: Thirteen potential areas of research were identified, some of which represented preparatory work rather than research per se. The three most highly ranked priorities were the documentation of data fields in each country's hospital administrative data (average score 8.4), the translation of patient safety indicators from ICD-9 to ICD-10 (average score 8.0), and the development and validation of algorithms to verify the logic and internal consistency of coding in hospital abstract data (average score 7.0). CONCLUSION: The group discussions resulted in a list of expert views on critical international priorities for future methodological research relating to health administrative data. The consortium's members welcome contacts from investigators involved in research using health administrative data, especially in cross-jurisdictional collaborative studies or in studies that illustrate the application of ICD-10.

In a retrospective study of chronic obstructive pulmonary disease inpatients, respiratory comorbidities were significantly associated with prognosis.

BACKGROUND AND OBJECTIVE: Comorbidities may be related to the prognosis for chronic obstructive pulmonary disease (COPD). We examined respiratory comorbidities associated with length of stay and in-hospital mortality among COPD patients. METHODS: We used the Hospital Person Oriented Information (HPOI) database of Statistics Canada for a 5-year period. Over 4 years (fiscal years 1994-1995 to 1998-1999), 143,135 records listed COPD as the most responsible diagnosis for men and 122,065 records for women aged 40 years or more, and 75,780 men and 69,539 women were admitted to hospital at least once. Logistic regression modeling was used to examine the relationships between respiratory comorbidities and hospital outcomes adjusting for covariates. RESULTS: Of the COPD patients, 10% had pneumonia-influenza and 3% had asthma as comorbid conditions. Women had a higher prevalence of asthma than men. The median length of stay at hospital was approximately 7 days, and 95% of patients were discharged alive. The odds ratio (95% confidence interval) for pneumonia-influenza in relation to in-hospital death was 3.56 (3.31, 3.83) for men and 3.29 (3.00, 3.61) for women. For comorbid asthma the corresponding odds ratios were 0.56 (0.36, 0.61) and 0.54 (0.35, 0.57), respectively. CONCLUSIONS: COPD inpatients with pneumonia-influenza had a worse prognosis and those with asthma had a better prognosis.

Regional variation in self-reported heart disease prevalence in Canada.

BACKGROUND: Cardiovascular disease is the leading cause of death in Canada. OBJECTIVE: To provide an analysis of the self-reported prevalence of heart disease and three specific cardiac conditions--myocardial infarction (MI), angina and congestive heart failure (CHF)--in subgroups of the Canadian population. METHODS: Data from the Public Use Microdata File from Statistics Canada's 2000/2001 Canadian Community Health Survey (CCHS) were used to estimate the crude self-reported prevalence of heart disease, MI, angina and CHF in Canada. The data are reported by age and sex groups, as well as by province or territory and health region. RESULTS: Based on the 2000/2001 CCHS data, it was estimated that among Canadians 12 years of age and older, 5.0% (n=1,286,000) have heart disease, 2.1% (n=537,000) have had a heart attack, 1.9% (n=483,000) have angina and 1.0% (n=264,000) have CHF. Marked variation in the prevalence of heart disease and the other specific cardiac conditions exists across age and sex groups, and across geographical regions. The prevalence of heart disease is low among those younger than 50 years; thereafter, the prevalence of heart disease increases and is more common among men than among women. By 70 years of age, at least one in four men and one in five women report having heart disease. Large differences in the burden of heart disease were observed across provinces, territories and health regions. Comparison of the highest and lowest prevalence rates among provinces and territories revealed a 1.9-fold difference for heart disease, a 2.8-fold difference for MI, a 2.3-fold difference for angina and a 3.3-fold difference for CHF. CONCLUSIONS: Large regional differences in the prevalence of heart disease and other specific cardiac conditions were observed across Canada. These data may assist health system planners to identify those regions and population subgroups most affected by heart disease, and to support the development of heart disease prevention and treatment programs.

Sex difference in hospitalization due to asthma in relation to age.

To describe the sex and age differences in asthma hospitalization among the Canadian population, we conducted an analysis based on a total of 9,486,173 hospital records in Canada for a 3-year period (1994/1995, 1995/1996, and 1996/1997), including 204,304 asthma patients and 288,977 asthma-related records. Asthma as one of the first five diagnoses, accounted for 3.0% of total hospitalizations, which was almost constant across the 3-year study period. The 3-year cumulative incidence of asthma hospitalization was substantially higher for young boys than girls, and it was reversed for adults. The incidence ratio for females vs. males for asthma hospitalization reached 2.8 for individuals 25 to 34 years of age, decreased gradually with increasing age, and then approached unity for those aged 80 years or more. The data suggest that sex is an important determinant for asthma, and the sex effect varies considerably over a life span.

Hospital readmissions for asthma in children and young adults in Canada.

To examine the incidence rate of hospital readmission for asthma in relation to sex and age among Canadian children and young adults, we used data from 86,863 subjects under age 20 years when they had a first admission for asthma as 1 of first 5 diagnoses in Canada between April 1, 1994 and March 31, 1997. We calculated age- and sex-specific incidence rates, and used the Cox proportional hazards model for multivariate analysis. Of these subjects, 20,277 (23.3%) were readmitted to hospital for asthma during the study period. After adjusting for length of stay for first admission and province, the rate ratio for females vs. males was 0.86 for those under age 1 year, and close to unity for the 1-4-year and 5-9-year age groups, whereas it was 1.47 and 1.35 for the 10-14-year and 15-19-year age groups, respectively. The data showed similar trends for rehospitalization asthma as a primary diagnosis. The incidence rate of rehospitalization showed little sex difference between ages 1-9 years, but was markedly higher in females than in males 10-19 years of age. Airway size, female hormonal changes, increased use of cosmetic products, and cigarette smoking among adolescent girls may contribute to the age- and sex-differences in adolescence.

Ecological measures of socioeconomic status and hospital readmissions for asthma among Canadian adults.

BACKGROUND: Lack of an association between area-based socioeconomic status (SES) and readmission for asthma was investigated in a country with a universal health care system. METHODS: Data linkage analysis was conducted based on hospitalization data from Statistics Canada's Person-oriented Information Database and area-based SES data from the 1996 Census. Hospital records for 8333 asthma patients aged 20-64 years in all Canadian provinces except Quebec who were admitted in 1995/1996 were linked to determine the number of patients who were rehospitalized within the same fiscal year. The area-based SES of the patients was defined according to the average personal income and proportion of residents with a university degree in an enumeration area (EA). Incidence rates of readmission for asthma were calculated based on the total years at risk. Cox's proportional hazard model was used to adjust for age, sex, province, and length of stay for first admission. RESULTS: The incidence rate of asthma rehospitalization was 31.6 per 100 person-years for men and 37.2 per 100 person-years for women. Neither average EA income or education level was significantly associated with rehospitalization for asthma. Women living in poor areas tended to have an increased incidence of asthma rehospitalization, but the difference was not significant after adjustment for covariates using the Cox regression model. CONCLUSION: Socioeconomic status measured at the neighborhood level has no significant impact on rehospitalization for asthma among Canadian adults.

Burden of cardiovascular disease in Canada.

BACKGROUND: This report updates the death estimates for cardiovascular disease (CVD) in Canada and introduces a population-based perspective on disease prevalence and health-related quality of life (HRQOL) burden. METHODS: The Canadian Mortality Database was used to estimate the mortality of men and women in different age groups for the 139 Canadian health regions from 1950 to 1999. Heart disease prevalence and its impact on HRQOL were estimated using the 2000-2001 Canadian Community Health Survey (CCHS). Life table techniques were used to estimate the impact of heart disease on life and health expectancy. RESULTS: Although CVD remains the leading cause of death in Canada, between 1950 and 1999 the death rates from CVD dropped from 702 per 100,000 to 288 per 100,000 men, and from 562 per 100,000 to 175 per 100,000 women. Results from the CCHS indicated that 5.4% of men and 4.6% of women reported having heart disease as diagnosed by a medical professional. Of these individuals, 14% of men and 21% of women reported difficulty ambulating - about six times more than people without heart disease. In total, 4.5 years of life expectancy and 2.8 years of health expectancy were lost due to CVD. The study also found large differences in the burden of CVD among men and women and across the 139 Canadian health regions. CONCLUSIONS: CVD is a major disease burden in terms of both mortality and HRQOL and is an important source of health inequalities between populations in Canada. Any attempt to improve the health of Canadians or to reduce health inequalities should include interventions to reduce CVD mortality and morbidity. Given the present impact of CVD on HRQOL, reducing or eliminating heart disease may potentially result in an increase in life expectancy that will be larger than the gains in health expectancy.