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Biomedical subjects

Helen Johansen

Publications and source records attributed to Helen Johansen.

At least 19 recordsLinked to original sources
PubMed2006

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 > or = 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.

Adult↗
PubMed2006

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.

Algorithms↗
PubMed2006

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.

Adult↗
PubMed2006

The effect of universal influenza immunization on vaccination rates in Ontario.

OBJECTIVES: This article examines the association between introduction of Ontario's Universal Influenza Immunization Program and changes in vaccination rates over time in Ontario, compared with the other provinces combined. DATA SOURCES: The data are from the 1996/97 National Population Health Survey and the 2000/01 and 2003 Canadian Community Health Survey, both conducted by Statistics Canada. ANALYTICAL TECHNIQUES: Cross-tabulations were used to estimate vaccination rates for the total population aged 12 or older, for groups especially vulnerable to the effects of influenza, and by selected socio-demographic variables. Z tests and multiple logistic regression were used to examine differences between estimates. MAIN RESULTS: Between 1996/97 and 2000/01, the increase in the overall vaccination rate in Ontario was 10 percentage points greater than the increase in the other provinces combined. Increases in Ontario were particularly pronounced among people who were: younger than 65, more educated, and had a higher household income. Between 2000/01 and 2003, vaccination rates were stable in Ontario, while rates continued to rise in the other provinces. Even so, Ontario's 2003 rates exceeded those in the other provinces.

Adolescent↗
PubMed2005

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.

Adult↗
PubMed2005

Changing age-pattern of hospitalisation risk of chronic obstructive pulmonary disease in men and women in Canada.

OBJECTIVE: To examine the changing pattern of age distributions of hospitalisation for chronic obstructive pulmonary disease (COPD) among Canadian men and women. DESIGN: Retrospective cohort study. PARTICIPANTS: 257,604 COPD inpatients aged 55-90 years with 463,089 hospital admissions during a 3-year study period (1994/95, 1995/96 and 1996/97) in Canada. MAIN OUTCOME MEASURES: COPD listed as one of the first five underlying diagnoses (broad definition, 463,089 hospitalisations) or as first diagnosis (narrow definition, 142,770 hospitalisations). RESULTS: Overall, men were more likely to have hospitalisations for COPD and had a higher proportion of death at hospital than did women. The 3-year cumulative incidence was 42.2/1,000 for the broadly defined COPD hospitalisation and 14.0/1,000 for the narrowly defined COPD hospitalisation, and steadily increased with increasing age. The relative risk for women versus men gradually increased with decreasing age, and was significantly greater than unity in the 55-59 year group for narrowly defined COPD hospitalisation. CONCLUSIONS: In terms of impact on secondary care COPD is a disease of the elderly and is becoming more common in women, particularly in younger age groups.

Age Distribution↗
PubMed2005

Improving population attributable fraction methods: examining smoking-attributable mortality for 87 geographic regions in Canada.

Smoking-attributable mortality (SAM) is the number of deaths in a population caused by smoking. In this study, the authors examined and empirically quantified the effects of methodological problems in the estimation of SAM through population attributable fraction methods. In addition to exploring common concerns regarding generalizability and residual confounding in relative risks, the authors considered errors in measuring estimates of risk exposure prevalence and mortality in target populations and estimates of relative risks from etiologic studies. They also considered errors resulting from combining these three sources of data. By modifying SAM estimates calculated using smoking prevalence obtained from the 2000-2001 Canadian Community Health Survey, a population-based survey of 131,535 Canadian households, the authors observed the following effects of potential errors on estimated national SAM (and the range of effects on 87 regional SAMs): 1) using a slightly biased, mismatched definition of former smoking: 5.3% (range, 1.8% to 11.6%); 2) using age-collapsed prevalence and relative risks: 6.9% (range, 1.1% to 15.5%) and -15.4% (range, -7.9% to -21.0%), respectively; 3) using relative risks derived from the same cohort but with a shorter follow-up period: 8.7% (range, 4.5% to 11.8%); 4) using relative risks for all diseases with age-collapsed prevalence: 49.7% (range, 24.1% to 82.2%); and 5) using prevalence estimates unadjusted for exposure-outcome lag: -14.5% (range, -20.8% to 42.6%) to -1.4% (range, -0.8% to -2.7%), depending on the method of adjustment. Applications of the SAM estimation method should consider these sources of potential error.

Canada↗
PubMed2005

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.

Adolescent↗
PubMed2004

Regional outcomes of heart failure in Canada.

BACKGROUND: Heart failure is a condition associated with significant mortality and morbidity. However, demographic features and outcomes following hospitalization for heart failure, and associated regional comparisons have not been performed in Canada. METHODS: Anonymously rendered records of patients hospitalized for incident heart failure in Canada were selected from the Canadian Institute for Health Information discharge abstract and hospital morbidity databases from fiscal years 1997/1998 to 1999/2000. The demographics, in-hospital mortality rate and heart failure readmission rates were compared among provinces and health regions. RESULTS: A total of 83,406 patients were hospitalized for heart failure across Canada during the study period. The number of cases increased dramatically with each decade after age 50 years, with 85% of hospitalized patients being age 65 years and over. On average, in-hospital mortality per index admission in Canada was 9.5 deaths per 100 hospitalized cases. While the greatest burden of readmissions was among those 65 years of age and over, heart failure readmission rates were similar across age groups. Among all patients surviving the index admission, heart failure readmission rates were 8.7%, 14.1% and 23.6% at 30 days, 90 days and one year, respectively. The highest age- and sex-adjusted in-hospital mortality rates were 11.9% (95% CI 10.6 to 13.2) in Newfoundland/Labrador and 11.6% (95% CI 10.6 to 12.7) in Nova Scotia. The highest readmission rates at one year were 26.9% (95% CI 24.9 to 28.9) in Newfoundland/Labrador, 26.3% (95% CI 25.0 to 27.7) in Saskatchewan and 25.2% (95% CI 24.3 to 26.1) in British Columbia. There were significant regional variations in heart failure readmission rates and mortality. CONCLUSIONS: There is a great burden of heart failure in Canada, increasing significantly with age. The mortality and readmission rates for this condition are high and exhibit variation among health regions and provinces. Factors contributing to regional variations in these outcomes merit further study.

Adult↗
PubMed2004

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.

Adult↗
PubMed2004

Cardiac procedures after an acute myocardial infarction across nine Canadian provinces.

BACKGROUND: Geographical variations in the use of invasive cardiac procedures have been documented. It remains unclear to what extent these variations exist across the Canadian provinces. OBJECTIVE: To describe variation in the use of invasive cardiac procedures and waiting times for these procedures across nine Canadian provinces. METHODS: Using longitudinal, de-identified patient data from the Canadian Institute for Health Information, records of patients who had suffered an acute myocardial infarction (AMI) in each of nine Canadian provinces between 1997/1998 and 1999/2000 were selected. Rates and median waiting times for percutaneous coronary intervention and coronary artery bypass graft surgery were calculated by age, sex and health region. RESULTS: There was a large variation in the use of and waiting times for invasive cardiac procedures across the Canadian provinces studied. In general, cardiac procedure rates in Western provinces were higher than in Eastern provinces, most notably higher than in the Maritime provinces and Ontario. In addition to interprovincial variation, there was also significant regional variation in the rates of revascularization and waiting times. Rates of percutaneous coronary intervention increased over the study period, whereas rates of bypass surgery remained relatively stable. CONCLUSIONS: Significant variation in the use of cardiac procedures after AMI exists across Canada and this April represent potential inequalities in the treatment of AMI across Canada.

Adult↗
PubMed2004

Influenza vaccination.

OBJECTIVES: This article compares influenza vaccination rates in 1996/97 and 2000/01 and describes the characteristics of adults who were vaccinated. DATA SOURCES: The data on influenza vaccination are from the 1996/97 National Population Health Survey and the 2000/01 Canadian Community Health Survey, both conducted by Statistics Canada. Data on hospitalizations and deaths are from the Hospital Mortality Data Base and the Canadian Mortality Data Base, respectively. ANALYTICAL TECHNIQUES: Cross-tabulations were used to estimate rates of vaccination among seniors, people with chronic conditions, and the total population aged 20 or older. Multiple logistic regression was used to assess relationships between being vaccinated and selected characteristics. MAIN RESULTS: Between 1996/97 and 2000/01, the percentage of Canadians aged 20 or older who reported having had a flu shot the previous year rose from 16% to 28%. Rates were higher for seniors and people with chronic conditions. The odds of vaccination were high for residents of middle-to-high income households, people with at least some postsecondary education, former smokers, and people with a regular doctor. Smokers and people who reported their health as good to excellent had lower odds of being vaccinated.

Adult↗
PubMed2004

Shorter hospital stays for breast cancer.

OBJECTIVES: This article examines trends in and factors influencing the length of stay for female breast cancer patients who were hospitalized between 1981 and 2000. DATA SOURCES: The hospital data are from the Hospital Morbidity Database and the Health Person-oriented Information Database, both maintained by Statistics Canada. Data on new cases of breast cancer are from the Canadian Cancer Registry and the National Cancer Incidence Reporting System. ANALYTICAL TECHNIQUES: Descriptive analyses present length of stayfor all hospital admissions with a primary diagnosis of breast cancer, by four-year period and by the patient's age, cancer stage, comorbid conditions and surgical procedures. Logistic regression is used to examine associations between these factors and length of stay. MAIN RESULTS: Since the early 1980s, the average length of stay in hospital for female breast cancer has fallen from 15.1 to 4.5 days. Declines occurred regardless of age group, cancer stage, procedure and comorbid conditions. Average stays first began to fall for less serious cases, but were eventually apparent for even the most serious.

Adult↗
PubMed2003

On the rise: The current and projected future burden of congestive heart failure hospitalization in Canada.

BACKGROUND: The incidence of congestive heart failure (CHF) has increased due, in part, to an aging population and improvements in the diagnosis and treatment of myocardial infarction. This has been reported internationally but no systematic epidemiological assessment of CHF has been conducted for Canada nationally. OBJECTIVES: To estimate length of stay, mortality and readmission rates and projected number of future CHF hospital patients. METHODS: Health insurance numbers were used to link all hospital visits for 1996/97 CHF patients who had no CHF discharges within the previous two years. All patients were followed up for one year from the date of their initial visit. RESULTS: The numbers of males and females in the study were similar: 40,958 males and 42,255 females. Within the first year, CHF patients used an average of 26.9 hospital days and nearly 50% were readmitted to hospital. Within the index episode, 16.5% of the CHF patients died in hospital. Under the age of 70, female patients had higher mortality than males, while after the age of 70, males were more likely to die. The number of CHF incident hospital cases per year is projected to more than double by the year 2025. To keep the current number of incident patients the same as in 1996/97, the incidence of would have to decrease by 2.6% per year. CONCLUSIONS: Patients admitted with CHF have high rates of mortality and prolonged and recurrent hospitalization. If the current rates are not reduced, health care costs related to CHF could increase substantially.

Adult↗
PubMed2003

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.

Adolescent↗