Asthma In Canada Research Articles

Budesonide/formoterol maintenance and reliever therapy: impact on airway inflammation in asthma

The aim of the present study was to compare the effectiveness, safety and health economics of budesonide/formoterol maintenance and a novel reliever therapy with conventional best practice in patients with persistent asthma in Canada. After 2 weeks of usual therapy, 1,538 patients were randomised for 6 months to open-label budesonide/formoterol maintenance and reliever therapy 160/4.5 microg twice daily and as needed, or to guideline-based conventional best practice. Severe asthma exacerbations, reliever medication use and total inhaled corticosteroid dose were analysed in all patients and airway inflammation was assessed in a sub-study of 115 patients. No differences were seen in time to first severe exacerbation and severe asthma exacerbation rate. There were numerically fewer emergency room visits or hospitalisations with budesonide/formoterol maintenance and reliever therapy (4.4 versus 7.5 events per 100 patients x yr(-1), 41% reduction); however, this did not reach statistical significance. Mean total inhaled corticosteroid dose, reliever use, asthma medication costs and total annual costs per patient were all significantly lower with budesonide/formoterol maintenance and reliever therapy. Mean sputum eosinophil cell counts remained in the range for controlled inflammation in both groups. In conclusion, budesonide/formoterol maintenance and reliever therapy achieved similar or improved clinical control compared with conventional best practice, with significantly lower total inhaled corticosteroid dose and lower cost, while maintaining similar control of eosinophilic inflammation.

Mepolizumab

Mepolizumab is an anti-interleukin-5 monoclonal antibody that is in clinical trials with GlaxoSmithKline (GSK) for the treatment of severe asthma, nasal polyposis and hypereosinophilic syndrome and eosinophilic oesophagitis (the latter two indications are classed as eosinophilia in the phase table). Interleukin-5 stimulates the production, activation and maturation of eosinophils. Since mepolizumab inhibits interleukin-5 and has a long terminal half-life, treatment with mepolizumab causes a sustained reduction in the numbers of circulating eosinophils. Thus, mepolizumab may be a useful therapeutic agent for the treatment of conditions characterized by increased levels of eosinophils. Hypereosinophilic syndrome is a rare idiopathic disease with broad clinical signs and symptoms that is diagnosed based on a persistent blood eosinophil count of >1500 cells, various end-organ damages (including skin, heart, lung, nervous system and digestive system), and with exclusion of known secondary causes of hypereosinophilia. Mepolizumab is in clinical trials for the treatment of hypereosinophilic syndrome, eosinophilc oesophagitis, severe asthma (in patients with airway eosinophilia) and nasal polyposis. GlaxoSmithKline (GSK) has completed enrolment in a phase II study of mepolizumab in 20 patients with symptomatic eosinophilic bronchitis with or without asthma in Canada. The randomized, double-blind, placebo-controlled study is evaluating the effects of intravenous mepolizumab on asthma control, airway eosinophilia and the degree to which concomitant corticosteroid treatment can be reduced (NCT00292877). In previous clinical studies, including trials in the EU and US, mepolizumab has shown a lack of effect on allergen-induced airway responses and inflammation despite a significant reduction in blood and sputum eosinophil levels.A randomized, double-blind, placebo-controlled, multicentre, phase III study of mepolizumab over 9 months in 85 patients with hypereosinophilic syndrome was completed in 2006. All patients have been offered, and continued in, a phase III, open-label, long-term extension study of mepolizumab. Enrolment in this study was completed in September 2006.A phase III, compassionate use trial of mepalizumab (NCT00244686) in patients with hypereosinophilic syndrome was ongoing in October 2007 in the US. Patients who have significant clinical disease but are unresponsive to traditional treatment and those who have demonstrated clinical benefit from previous anti-IL-5 treatment are eligible to take part in the trial. Mepolizumab received orphan drug status for first-line treatment in patients with hypereosinophilic syndrome in the US and the EU in 2004. Mepolizumab is also in phase I/II clinical development for the treatment of eosinophilic oesophagitis. A phase I/II trial (NCT00358449) began in August 2006 in the US, Australia, the UK and Canada, and will enrol approximately 72 paediatric patients with eosinophilic oesophagitis. The randomized, parallel-group clinical trial will evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics of intravenous mepolizumab for 12 weeks. In September 2006, GSK completed enrolment in a phase I/II study of mepolizumab for the treatment of eosinophilic oesophagitis in ten adult patients in Switzerland (NCT00274703). The randomized, double-blind, placebo-controlled study will evaluate the pharmacokinetics, pharmacodynamics, safety and tolerability of IV mepolizumab.A phase I/II trial of mepolizumab in four patients with eosinophilic oesophagitis conducted by Cincinnati Children's hospital found the monoclonal antibody was safe and effective. Brigham and Women's Hospital in association with GSK is conducting a phase I/II trial of mepolizumab in patients with Churg-Strauss Syndrome (CSS) in the US. The trial, which started in September 2007, will evaluate the potential of mepolizumab to reduce the need for corticosteroid therapy in patients with CSS (NCT00527566). CSS, otherwise known as allergic granulomatosis, is defined by patients with asthma, eosinophilia and vasculitis.

Can Workplace Education Improve the State of Asthma in Canada?

Can Workplace Education Improve the State of Asthma in Canada?

SYMPTOM CONTROL, PATIENT SATISFACTION, AND TREATMENT COMPLIANCE IN PATIENTS WITH MILD ASTHMA PRESCRIBED LOW-DOSE INHALED CORTICOSTEROIDS

PURPOSE: Low dose inhaled corticosteroids (ICS) are the first line treatment for mild asthma in Canada. However, non compliance may reduce asthma control and lower patient satisfaction. To describe in a “real-world” setting the percentage of mild asthmatics being at least 6 years old whose symptoms are uncontrolled with low-dose ICS and to assess the association between treatment compliance, asthma symptom control and patient satisfaction.

Socioeconomic status and medication prescription patterns in pediatric asthma in Canada

Purpose To investigate whether the socioeconomic status of children and adolescents with asthma is associated with optimal use of asthma medications in a health care system that provides free access to prescribed medications. Methods A cohort of 29,018 children (5–12 y) and adolescents (13–17 y) with asthma was reconstructed from the administrative health database of the Régie de l’assurance maladie du Québec in Canada. Adherence to the Canadian Asthma Guidelines was compared between low-income patients (patients living in families receiving social assistance) and higher-income patients (patients living in middle-class families with working parents). Both groups of patients had free, universal access to medical care and prescribed medications. Patients were considered adherent if they had: (1) 10 doses or fewer of a short-acting β 2-agonist (SABA) per week or (2) greater than 10 doses of a SABA per week plus greater than 1,000 μg of beclomethasone chlorofluorocarbon (CFC) per day. A second definition of adherence was used in which the 10 doses of SABA were replaced by 3 doses. Results Our cohort comprised 7,454 adolescents and 21,564 children. Within each definition, low-income adolescents had similar rates of adherence as higher-income adolescents ( p = .08–.4). Low-income children, however, had lower rates of adherence than higher-income children when the first definition of adherence was used (76% vs. 80%; p < .001). Conclusion Our study showed that socioeconomic status had a small influence on the likelihood of receiving treatment in adherence with the Canadian Asthma Guidelines among children, whereas no association was detected among adolescents.

Women and Asthma: Lessons from a Gender Analysis of the Asthma in Canada Survey

Objective. To compare the degree of asthma control achieved by men and women with asthma in Canada and to explore differences in patient perspectives, treatments used, and health care resources used between men and women with asthma. Design. Population-based cross-sectional telephone interview survey of Canadians with doctor-diagnosed asthma.Subjects and methods. Random digit dialing was used to identify a representative sample of Canadians with asthma. A total of 801 adults were interviewed over the telephone. Analysis was performed on the data from a subgroup of 20- to 50-year-old patients with asthma who participated in the original survey (329 women and 183 men).Results. Women and men were equally likely to be poorly controlled (58% vs. 56%, p > 0.05) as defined by failing to meet two or more of six symptom-based criteria listed by the 1996 Canadian Asthma Consensus (CAC) Guidelines as appropriate treatment targets. However, there were significant differences in medication used; women were more likely than men to use an inhaled corticosteroid in the treatment of their asthma (59% vs. 45%, p < 0.05) and were more knowledgeable about their appropriate use (62% vs. 46%, p < 0.05), and were more likely to be satisfied with their physicians' care. Despite this, women were more likely than men to have required urgent care for their asthma in the year preceding the survey (50% vs. 36%, p < 0.05).Conclusion. Women report greater need for urgent asthma care despite more frequent use of inhaled corticosteroids and better asthma knowledge scores than men.

Higher BMI is associated with worse asthma control and quality of life but not asthma severity

Asthma and obesity tend to co-occur, but relatively few studies have linked obesity, measured using body mass index (BMI), to clinically relevant measures of asthma morbidity. This study assessed BMI in a Canadian sample of asthma outpatients, and evaluated associations between BMI and levels of asthma severity, asthma control, and asthma-related quality of life. A total of 382 adult asthma patients underwent demographic and medical history interviews on the day of their clinic visit. Patients' self-reported height and weight were used to calculate BMI (kg/m(2)). Asthma severity was classified according the GINA (2002) guidelines. Patients completed the Asthma Control (ACQ) and Asthma Quality of Life (AQLQ) Questionnaires and underwent standard pulmonary testing (spirometry). A total of 139 (36%) patients had a normal BMI; 149 (39%) patients were overweight; and 94 (25%) patients were obese. There was no relationship between BMI and asthma severity when controlling for age and sex. Patients with higher BMI scores had higher ACQ and lower AQLQ scores, independent of age, sex and asthma severity. Results identify higher BMI and obesity as potential behavioral factors related to worse asthma control and quality of life, but not asthma severity, and suggest important avenues for asthma management and control initiatives.

Urgent Care Costs of Uncontrolled Asthma in Canada, 2004

It has been more than a decade since Krahn evaluated the direct and indirect costs of asthma in Canada. Asthma is often uncontrolled and the cost of providing urgent care has not been determined. Hospitalizations, unscheduled physician visits, emergency department visits, drug treatments and ambulance rides are resources used by the uncontrolled asthmatic population, resulting in 162 million US dollars in costs annually. Improved control of asthma could decrease these costs.

Influence of outdoor aeroallergens on hospitalization for asthma in Canada

Background The risk of hospitalization for asthma caused by outdoor aeroallergens is largely unknown. Objective The objective of this study was to determine the association between changes in outdoor aeroallergens and hospitalizations for asthma from the Pacific coast to the Atlantic coast of Canada. Methods A daily time series analysis was done to test the association between daily changes in aeroallergens and daily changes in hospitalizations for asthma during a 7-year period between 1993 and 2000 in 10 of the largest cities in Canada. Results were adjusted for long-term trends, day of the week, climate, and air pollution. Results A daily increase, equivalent to the mean value of each allergen, was associated with the following percentage increase in asthma hospitalizations: 3.3% (95% CI, 2.3 to 4.1) for basidiomycetes, 3.1% (95% CI, 2.8 to 5.7) for ascomycetes, 3.2% (95% CI, 1.6 to 4.8) for deuteromycetes, 3.0% (95% CI, 1.1 to 4.9) for weeds, 2.9% (95% CI, 0.9 to 5.0) for trees, and 2.0% (95% CI, 1.1 to 2.8) for grasses. After accounting for the independent effects of trees and ozone, the combination of the 2 was associated with an additional 0.22% increase in admissions averaged across cities ( P < .05). Conclusion These findings provide evidence for the hypothesis that aeroallergens are an important cause of severe asthma morbidity across Canada, and in some situations there might be a modest synergistic adverse effect of ozone and aeroallergens combined.

Analysis of prevalence, triggers, risk factors and the related socio-economic effects of childhood asthma in the Student Lung Health Survey (SLHS) database, Canada 1996.

The purpose of this study was to provide information to improve the management of childhood asthma in Canada. The Student Lung Health Survey (SLHS) was conducted as a stratified and multi-staged cluster survey across Canada in 1996. It included a total of 136 public, private and separate schools in nine health units. The target study population was schoolchildren aged 5 to 19 years. Among all 5-19 years old students, the prevalence of asthma was 13.0%, with the prevalence for males being higher than for females, the adjusted Odds Ratio (OR) was 1.17, (95% CI 1.14-1.19) for males, in comparison with females. The prevalence in the 15-19 age group was higher than that in the 5-9 and 10-14 age group in females, but it was higher in the 5-9 and 10-14 age group than in the 15-19 age group in males. The mean delay from the onset of symptoms to time of first diagnosis was 1, 0.4 and 0.3 years for the 1-4, 5-9 and 10-14 age group respectively. However, there was no delay in the 15-19 group. The prevalence of asthma in Prince Edward Island (17.9%), Halifax (17.1%), and Kingston (16.1%) was higher than that in Saskatoon (10.0%). Sherbrooke (9.7%) and Kelowna (11.9%). The proportion of asthma for students who smoked more than 11 cigarettes per day (OR = 1.41), were exposed to passive smoke in home (OR = 7.29), in car (OR = 4.71), and in school (OR = 4.24) or had a family income less than CAN$40,000 (OR = 1.19), was significantly higher than groups without those factors. Risk factors and socio-economic status such as living conditions and environment, pets or plants in the home, parental education levels also affected the morbidity of asthma. The results of the SLHS study demonstrated the serious burden of childhood asthma, and asthma triggers, living and environmental conditions and lifestyle influence the prevalence and the effects of childhood asthma diagnosis, treatment, and education in Canada. Asthma is still a serious chronic condition for students and it influences their academic performance and their quality of life. The diagnostic methods and the practice guidelines for asthma control are useful for preventing and controlling asthma. These findings provide indications of interventions are being used for the control of asthma in Canada.

Control of asthma in Canada: failure to achieve guideline targets.

To assess the degree of asthma control achieved by patients with asthma in Canada and to describe the impact of poor asthma control. Population-based, cross-sectional telephone interview survey of Canadians with doctor-diagnosed asthma. Random digit dialing was used to identify a representative sample of Canadians with asthma. A total of 801 adults and 200 parents of children aged four to 15 years were interviewed over the telephone. Telephone interviews were also conducted with 266 physicians. Only 24% of patients achieved disease control by meeting the six symptom-based criteria listed by the 1996 Canadian Asthma Consensus Guidelines as appropriate treatment targets. Fifty-seven per cent of patients failed to meet two or more of the six control criteria and were considered poorly controlled. Fifty-one per cent had required urgent care for out of control asthma at least once in the year before the survey. Nonetheless, 91% of patients thought that their asthma was adequately controlled. Physicians shared this optimism: 77% of family physicians and 90% of respirologists believed that they were usually able to achieve optimal asthma control in their patients. Few physicians gauged asthma control by tracking more than one or two symptoms, and just over one-half (54%) of patients surveyed recalled ever having had a lung function test. One-half (48%) of patients with poorly controlled asthma who used inhaled steroids did not understand the role of inhaled steroids; one-third (32%) of patients with poorly controlled asthma who used short acting bronchodilators misunderstood the action of quick relief bronchodilators. The majority of Canadians with asthma suffer from inadequate control of their disease. Suboptimal control of asthma is associated with excess health care use. Inadequate monitoring by physicians and poor patient education may be factors contributing to this problem.

The Burden of Asthma Symptoms and the Positive Role of Patient Management

Background: Asthma is a major public health problem in developed countries. In Canada, the prevalence of asthma is approximately 5 to 7%, with some provincial variation. A retrospective study using data collected in 1990 estimated the total costs of asthma in Canada to be between $Can504 million and $Can648 million (1990 dollars). 61% of all asthma costs were direct costs ($Can306 million). Of these, drugs were the single largest component ($Can124 million). Illness-related disability ($Can76 million) was the largest contributor to indirect costs.

Management of acute asthma in Canada: An assessment of emergency physician behaviour

The study objective was to asssess Canadian emergency physicians for their management preferences and their compliance with recently developed guidelines for treatment of acute asthma in adults. The design was a cross-sectional survey sent to members of the Canadian Association of Emergency Physicians (CAEP) and to the emergency department (ED) directors of all Canadian hospitals with more than 25 beds in November 1992. ED directors who had not responded were sent a second survey in January 1993. The response rates for the survey were 60.1% ( 362 602 ) for ED directors and 53.4% ( 302 586 ) for CAEP members. Respondents were more likely to be from larger hospitals and to have completed some training beyond general practice level (CCFP, CCFP-EM, ABEM, FRCPC). There were wide variations among respondents in the use of objective measurements of asthma severity (forced expiratory volume in 1 s [FEV 1] and peak expiratory flow rates [PEFR]), dosing of bronchodilators, and utilization of systemic corticosteroids. Forty-six percent of respondents used the FEV 1 “occasionally” (22.3%) or “never” (23.8%), and 26.7% used PEFR “occasionally” (15.8%) or “never” (10.9%) in asthma management Ninety-seven percent used nebulized beta agonist “always” (71.3%) or “often” (25.6%), but only 48.5% used the metered dose inhaler (MDI) “always” (11%) or “often” (37.5%). More than a quarter of respondents (27.2%) used doses of beta agonists that were less than those recommended (>every 30–60 min). Oral corticosteroids were prescribed at discharge only “occasionally” (51.1%), “seldom” (18.9%), or “never” (6.5%) in 76.6% of physicians. Physicians with more training were more likely to assess and treat patients according to current asthma treatment guidelines. The survey shows that many Canadian emergency physicians did not follow published recommendations for the care of patients with acute asthma. This finding was especially so with regard to objective evaluation of airflow, aggressive use of beta-agonists, the use of corticosteroids, and in making appropriate arrangements for patient discharge and follow-up.

Epidemiological Trends in Asthma

Many markers of asthma morbidity have shown substantial increases over the past two decades, including family physician visits, use of anti-asthma medications, emergency room visits and hospital admissions. The reported prevalence of diagnosed asthma and of wheezing has increased, especially in children, with accompanying evidence of increased atopy and increased airway responsiveness. Allergen exposure and parental smoking are significant risk factors for childhood wheezing, whereas the influence of outdoor air pollution is uncertain. Increasing use of beta-agonist treatment, which appears to increase the severity of asthma by increasing early and late responses to allergen, may contribute to increased morbidity and mortality, especially if potent beta-agonists are used. Risk factors for asthma mortality include age, smoking, allergy and airway lability, as well as over-reliance on beta-agonists and poor compliance with other aspects of treatment. Following withdrawal of the potent beta-agonist fenoterol in New Zealand, both hospital admissions and mortality from asthma fell abruptly. Continued patient and physician education, with emphasis on avoidance of risk factors and use of appropriate treatment, should reduce morbidity and mortality from asthma in Canada.

Canadian Asthma Consensus Conference Summary of Recommendations

The Asthma Committee of the Canadian Thoracic Society invited a group of Canadian physicians with a particular interest in asthma to meet in Montebello, Quebec, March 9‐12, 1995 to arrive at a consensus statement on the optimal approach to the management of asthma in the pediatric and adult ambulatory care settings. The societies and associations represented are listed in the appendix with the names of the contributors to this document. The objectives of the Montebello conference were: 1. To review the current ambulatory care management of asthma in Canada; 2. To develop guidelines with the participation of family physicians and specialists; 3. To develop guidelines which are evidence‐based; 4. In creating evidence‐based guidelines to focus attention on aspects of asthma management that are currently not supported by randomized controlled trials; 5. To develop strategies that allow for the implementation of rational guidelines at a local level. Recommendations were based on a critical review of the scientific literature by small groups prior to the meeting and are categorized according to the strength of the scientific evidence supporting each recommendation (Table 1).

House dust mite allergen levels in two cities in Canada: effects of season, humidity, city and home characteristics

The homes of 120 patients with asthma, 57 in Vancouver and 63 in Winnipeg, were studied. The characteristics of the homes were assessed by a questionnaire. Dust samples were collected and the indoor relative humidity was measured four times during the year covering all four seasons in both cities. Mite allergen levels were determined using monoclonal antibodies against Der p I and Der f I by the ELISA method. The mean levels of both mite allergens in mattress and floor samples in the homes in Vancouver and in Winnipeg were relatively low for all seasons. Mite allergen levels were found to be associated with city, season and individual home differences. They were significantly higher in Vancouver than in Winnipeg. Der p I and Der f I in mattress samples in both cities and Der f I in floor samples in Vancouver, varied by season. The indoor relative humidity level in the homes in Vancouver were also significantly higher than those in Winnipeg. There was, however, no significant association between the levels of indoor relative humidity and the levels of mite allergens after adjusting for variations in city, season and individual home. Although individual home differences were highly associated with mite allergen levels, only a few home characteristics were found to be related to mite allergen levels such as the type and the age of the home, the type of heating, the use of feather pillows and the number of occupants in the homes. Whether low levels of mite allergens are partially responsible for the relatively low prevalence of childhood asthma in Canada remains to be investigated.

Asthma Mortality in Canada, 1946 to 1990

OBJECTIVE: To assess the impact of asthma on Canadian mortality rates over a 45‐year period.DESIGN: A descriptive, population‐based study.SETTING: Canada.SUBJECTS: All persons who died from asthma in Canada from 1946 to 1990 as reported to Statistics Canada in Ottawa.MAIN OUTCOME MEASURES: Standardized mortality ratios, age‐specific patterns of death, potential years of life lost (PYLL) and life expectancy lost.RESULTS: A total of 12,010 male and 8486 female asthma deaths were recorded in Canada from 1946 to 1990. Mortality rates for both sexes declined from a high of between three to six deaths in 1951 to 1955 to approximately two deaths per 100,000 in 1986 to 1990, with the decline in rates being greater for males than females. Age‐specific mortality rates were highest al all ages in 1951 to 1955, except for 15 to 24 years when deaths rates for the 1981 to 1985 period were greater. PYLL exhibit the same pattern as mortality, peaking in 1951 to 1955 and subsequently declining with each period. Loss in life expectancy due to asthma was about one month (not significant) in all time periods.CONCLUSIONS: Asthma mortality rates have declined significantly over the study period. This decline appears to be linked with the convergence of sex‐specific rates and with changes in the patterning or age‐specific mortality. The impact of asthma on the life expectancy of Canadians is small.

Prevalence of childhood asthma across Canada.

A large cross-sectional study provided an opportunity to estimate the prevalence of childhood asthma in several regions across Canada. In 1988, approximately 18,000 questionnaires were distributed to the families of 5-8 year old children in 30 communities from the following six regions across Canada: the interior of British Columbia, southeastern Saskatchewan, southwestern Ontario, the central region of Ontario, southern Quebec, and the Maritimes (Nova Scotia and Prince Edward Island). These communities were free of point-source air pollutants and selected to represent a range of ambient sulphate concentrations. In all 14,948 questionnaires were returned representing an 83% response rate. Currently present, physician-diagnosed asthma was reported for 4.7% of children by their parents. Persistent wheezing was reported for 13% and persistent cough for 5.9%. Asthma was most common in the two Maritime provinces (7.4%), and least common in British Columbia (3.3%) and Quebec (3.4%). Similar regional differences were seen for persistent cough, persistent wheeze, and also hospital separation rates for asthma which were approximately 800 per 100,000 for the Maritimes and 396 per 100,000 for British Columbia. Differences persisted despite adjustments for several host and environmental (indoor and outdoor) characteristics. The east coast of Canada may be an endemic area of asthma in Canada. If confirmed by objective measures of asthma, a detailed aetiologic investigation could enhance understanding of this phenomenon and the major environmental determinants of asthma morbidity in general.

Paediatric Asthma in Canada

Paediatric Asthma in Canada