Helen Johansen

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.

Hypertension prevalence, awareness, treatment and control in national surveys from England, the USA and Canada, and correlation with stroke and ischaemic heart disease mortality: a cross-sectional study.

Objective Comparison of recent national survey data on prevalence, awareness, treatment and control of hypertension in England, the USA and Canada, and correlation of these parameters with each country stroke and ischaemic heart disease (IHD) mortality. Design Non-institutionalised population surveys. Setting and participants England (2006 n=6873), the USA (2007–2010 n=10 003) and Canada (2007–2009 n=3485) aged 20–79 years. Outcomes Stroke and IHD mortality rates were plotted against countries’ specific prevalence data. Results Mean systolic blood pressure (SBP) was higher in England than in the USA and Canada in all age–gender groups. Mean diastolic blood pressure (DBP) was similar in the three countries before age 50 and then fell more rapidly in the USA, being the lowest in the USA. Only 34% had a BP under 140/90 mm Hg in England, compared with 50% in the USA and 66% in Canada. Prehypertension and stages 1 and 2 hypertension prevalence figures were the highest in England. Hypertension prevalence (≥140 mm Hg SBP and/or ≥90 mm Hg DBP) was lower in Canada (19·5%) than in the USA (29%) and England (30%). Hypertension awareness was higher in the USA (81%) and Canada (83%) than in England (65%). England also had lower levels of hypertension treatment (51%; USA 74%; Canada 80%) and control (<140/90 mm Hg; 27%; the USA 53%; Canada 66%). Canada had the lowest stroke and IHD mortality rates, England the highest and the rates were inversely related to the mean SBP in each country and strongly related to the blood pressure indicators, the strongest relationship being between low hypertension awareness and stroke mortality. Conclusions While the current prevention efforts in England should result in future-improved figures, especially at younger ages, these data still show important gaps in the management of hypertension in these countries, with consequences on stroke and IHD mortality.

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 inhospital 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.

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

BackgroundHealth 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.MethodsA 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.ResultsThirteen 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 countrys 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).ConclusionThe group discussions resulted in a list of expert views on critical international priorities for future methodological research relating to health administrative data. The consortiums 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.

Increases in Antihypertensive Prescriptions and Reductions in Cardiovascular Events in Canada

The Canadian Hypertension Education Program, an extensive professional education program to improve the management of hypertension, was started in 1999. There were very large increases in diagnosis and treatment of hypertension in the first 4 years after initiation of the program. The purpose of this study was to examine the association between the changes in antihypertensive therapy with changes in hospitalization and death from major hypertension-related cardiovascular diseases in Canada between 1992 and 2003. Using various national databases, Canadian standardized yearly mortality and hospitalization rates per 1000 for stroke, heart failure, and acute myocardial infarction were calculated for individuals aged ≥20 years and regressed against antihypertensive prescription rates. Changes in rates were examined in a time series analysis. There were significant reductions (P<0.0001) in the rate of death from stroke, heart failure, and myocardial infarction starting in 1999. There was also a reduction in hospitalization rate from stroke (P<0.0001) and heart failure (P<0.0001) but not myocardial infarction in 1999. The changes in death (P<0.001 for all 3 diseases) and hospitalization (P<0.0001 for stroke and heart failure; P=0.018 for acute myocardial infarction) were associated with the increases in antihypertensive prescriptions. This study demonstrates that the reduction in cardiovascular death and hospitalization rates is associated with an increase in antihypertensive prescriptions and that it coincides with the introduction of the Canadian Hypertension Education Program. The Canadian Hypertension Education Program educational model for improving health care could be adopted by other countries with well-developed professional and scientific societies.

Neonatal characteristics as risk factors for preschool asthma

Childhood asthma usually begins early in life. Neonatal characteristics are reportedly predictive of symptom onset. This investigation utilized data from a provincial health organization to evaluate the effect of several birth characteristics on asthma incidence and hospitalization for asthma during age 0-4. Using logistic regression, the odds ratios (OR) for the following variables indicate a significant (p < 0.05) association with physician-diagnosed preschool asthma: male gender (OR = 1.72), birthweight < 1500 g (OR = 2.11), prematurity (OR = 1.34), respiratory distress syndrome (RDS) in the presence (OR = 2.95) or absence (OR = 1.61) of bronchopulmonary dysplasia (BPD), and transient tachypnea of the newborn (TTN; OR = 1.36). Male gender (OR = 1.91), birthweight < 1500 g (OR = 2.56), RDS with and without BPD (OR = 3.35 and 2.50, respectively), TTN (OR = 2.08), and severe birth asphyxia (OR = 1.94) showed an important association with hospitalization due to asthma. Neonatal characteristics are important determinants for the risk of preschool asthma, even after mutual adjustment.

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.

Large Increases in Hypertension Diagnosis and Treatment in Canada After a Healthcare Professional Education Program

This study was conducted to compare the self-reported prevalence and treatment of hypertension in adult Canadians before and subsequent to the implementation of the Canadian Hypertension Education Program in 1999. Data were obtained from 5 cycles of the Canadian Health Surveys between 1994 and 2003 on respondents aged ≥20 years. Piecewise linear regression was used to calculate the average annual increase in rates, before and after 1999. Between 1994 and 2003, the percentage of adult Canadians aware of being diagnosed with hypertension increased by 51% (from 12.37% to 18.74%; P<0.001), and the percentage prescribed antihypertensive drugs increased by 66% (from 9.57% to 15.86%; P<0.001). After 1999, there was approximately a doubling of the annual rate of increase in the diagnosis of hypertension (from 0.52% of the population per year before 1999 to 1.03% per year after 1999; P<0.001) and the percentage prescribed antihypertensive drugs (from 0.54% of the population per year before 1999 versus 0.98% per year after 1999; P<0.001). The proportion of those aware of the diagnosis of hypertension but not being treated with drugs was reduced by half between 1994 and 2003 (from 31.47% untreated to 15.34% untreated; P<0.001). There was a greater increase in awareness of hypertension and use of antihypertensive drugs among men compared with women after 1999. The large increase in the diagnosis and treatment of hypertension in Canada between 1994 and 2003 is consistent with an overall beneficial effect of the Canadian Hypertension Education Program, including a reduced gender gap in hypertension care.

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.

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.