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Biomedical subjects

Pierre Ernst

Publications and source records attributed to Pierre Ernst.

35 records · Page 2Linked to original sources
PubMed2004

Geographic and gender variability in the prevalence of bronchial responsiveness in Canada.

OBJECTIVES: Geographic variability in reported prevalences of asthma worldwide could in part relate to interpretation of symptoms and diagnostic biases. Bronchial responsiveness measurements provide objective evidence of a common physiologic characteristic of asthma. We measured bronchial responsiveness using the standardized protocol of the European Community Respiratory Health Survey (ECRHS) in six sites in Canada, and compared prevalences across Canada with international sites. DESIGN: Samples of 3,000 to 4,000 adults aged 20 to 44 years were randomly selected in Vancouver, Winnipeg, Hamilton, Montreal, Halifax, and Prince Edward Island, and a mail questionnaire was completed by 18,616 individuals (86.5%). Preselected random subsamples (n = 2,962) attended a research laboratory for examination including more detailed questionnaires, lung function testing including methacholine challenge, and skin testing with 14 allergens. RESULTS: Prevalences of bronchial hyperresponsiveness, measured as cumulative dose of methacholine required to produce a 20% fall from the post-saline solution FEV1 < or = 1 mg, ranged from 4.9% (95% confidence interval [CI], 1.6 to 8.5) in Halifax to 22.0% (95% CI, 18.1 to 26.0) in Hamilton (median, 10.7%). In all Canadian sites, bronchial hyperresponsiveness was more prevalent in women than in men. Neither the geographic nor gender differences were accounted for by differences in age, smoking, skin test reactivity, or baseline FEV1. Geographic- and gender-related variability changed little when only bronchial hyperresponsiveness associated with asthma-like symptoms was considered. CONCLUSIONS: A wide variability in bronchial responsiveness can occur within one country, almost as wide as the range found across all international sites participating in the ECRHS study and not explained by differences in gender, smoking, skin test reactivity, and FEV1. While gender variability in the prevalence of bronchial responsiveness is likely due to hormonal and immunologic factors, geographic variability is likely to result from environmental factors.

Adult↗
PubMed2003

Inhaled and nasal corticosteroid use and the risk of fracture.

Studies of the risk of fracture associated with inhaled corticosteroids are inconclusive and are limited to short-term effects. We assessed whether long-term use increases this risk. We conducted a case control study nested within a population-based cohort of all Quebec elderly dispensed respiratory medications and followed for at least 4 years during 1988-2001. There were 9,624 new cases of fracture of the hip or upper extremities and 191,622 age-matched control subjects (mean age of 81 years). The rate of any such fracture for current inhaled corticosteroid use was not elevated (rate ratio [RR], 0.97; 95% confidence interval [CI], 0.92-1.03). For upper-extremity fracture, the rate increased by 12% (RR, 1.12; 95% CI, 1.04-1.19) with every 1,000-microg increase in the daily dose of inhaled corticosteroids, but not for hip fracture (RR, 0.97; 95% CI, 0.88-1.07). Among subjects followed for over 8 years, the rate of hip fracture was only elevated with daily doses of more than 2,000 microg of inhaled corticosteroids (RR, 1.61; 95% CI, 1.04-2.50). The rate was not elevated at any dose of nasal corticosteroids. In conclusion, the long-term use of inhaled and nasal corticosteroids at the usual recommended doses is not associated with a risk of fracture in older patients with respiratory disease.

Administration, Inhalation↗
PubMed2003

Inhaled corticosteroid use in asthma and the prevention of myocardial infarction.

BACKGROUND: Asthma patients may be at increased risk of cardiovascular outcomes due to hypoxemia from asthma exacerbations and bronchodilator-induced tachycardia. We investigated whether inhaled corticosteroids, which are known to improve asthma control and reduce exacerbations, are associated with a lower rate of myocardial infarction. METHODS: We used the Saskatchewan Health databases to form a population-based cohort of subjects aged 5 to 44 years who were using antiasthma drugs between 1975 and 1991. Subjects were followed until 1997, the age of 55 years, or death. A nested case-control approach was used where each subject with a first myocardial infarction was matched on calendar time, age, and sex with up to 10 controls randomly selected from the cohort. RESULTS: The cohort consisted of 30,569 subjects, including 105 patients with myocardial infarction who were matched with 933 controls. The adjusted rate ratio of myocardial infarction for inhaled corticosteroid use during the year before the index date was 0.56 (95% confidence interval [CI]: 0.32 to 0.99) as compared with no use. Myocardial infarction decreased by 12% (95% CI: 0% to 23%) with each additional canister used during this 1-year period. The rate ratio of myocardial infarction for inhaled corticosteroid use was 0.78 (95% CI: 0.41 to 1.51) among patients with milder asthma and 0.19 (95% CI: 0.04 to 0.97) among those with more severe asthma. CONCLUSION: Inhaled corticosteroid use may reduce the risk of myocardial infarction in asthma patients, particularly those with more severe disease.

Administration, Inhalation↗
PubMed2003

Altitude-related hypoxia: risk assessment and management for passengers on commerical aircraft.

BACKGROUND: Individuals with pulmonary and cardiac disorders are particularly at risk of developing hypoxemia at altitude. Our objective is to describe the normal and maladaptive physiological responses to altitude-related hypoxia, to review existing methods and guidelines for preflight assessment of air travelers, and to provide recommendations for treatment of hypoxia at altitude. DATA SYNTHESIS: Falling partial pressure of oxygen with altitude results in a number of physiologic adaptations including hyperventilation, pulmonary vasoconstriction, altered ventilation/perfusion matching, and increased sympathetic tone. According to three guideline statements, the arterial pressure of oxygen (PaO2) should be maintained above 50 to 55 mm Hg at all altitudes. General indicators such as oxygen saturation and sea level blood gases may be useful in predicting altitude hypoxia. More specialized techniques for estimation of altitude PaO2, such as regression equations, hypoxia challenge testing, and hypobaric chamber exposure have also been examined. A regression equation using sea level PaO2 and spirometric parameters can be used to estimate PaO2 at altitude. Hypoxia challenge testing, performed by exposing subjects to lower inspired FIO2 at sea level may be more precise. Hypobaric chamber exposure, the gold standard, mimics lower barometric pressure, but is mainly used in research. CONCLUSION: Oxygen supplementation during air travel is needed for individuals with an estimated PaO2 (8000 ft) below 50 mmHg. There are a number of guidelines for the pre-flight assessment of patients with pulmonary and/or cardiac diseases. However, these data are based on small studies in patients with a limited group of diseases.

Aerospace Medicine↗
PubMed2002

The early course of newly diagnosed asthma.

PURPOSE: We describe the intensity of therapy for patients with newly diagnosed asthma and how it changed during subsequent years in relation to age, sex, and initial level of therapy. METHODS: We examined a cohort of 13,671 patients in Saskatchewan, Canada, who were initially between the ages of 5 and 44 years. Patients were followed prospectively, and the intensity of asthma therapy was measured during successive 12-month periods. RESULTS: Based on the intensity of asthma drug therapy during the first year after entry into the cohort, 6661 patients (48.7%) were initially prescribed therapy judged to be appropriate for mild asthma, and 977 (7.1%) were dispensed medications in a manner suggesting their asthma was severe; the remaining 6033 (44.1%) were classified as receiving treatment of intermediate intensity. Among patients initially classified as receiving treatment appropriate for mild disease, only about 3% were dispensed medications that suggested that their asthma had become severe during up to 5 years of follow-up. Intensity of therapy waned in a substantial proportion of patients who were initially classified as having severe asthma, especially if they were initially younger than 15 years of age. Thirty-four per 100 patients initially younger than 15 years old were receiving medications appropriate for mild asthma, and 23 per 100 such patients received no medication for asthma during a 12-month period when followed up to 5 years. CONCLUSION: Patients with asthma who are initially treated with therapy appropriate for mild asthma are rarely treated later with therapy suggesting the advent of severe disease. Patients initially dispensed medications suggesting the presence of severe asthma often see the intensity of treatment wane over time.

Adolescent↗
PubMed2002

Teaching time for metered-dose inhalers in the emergency setting.

OBJECTIVES: In some acute-care settings, practitioners are reluctant to institute bronchodilator therapy with metered-dose inhalers (MDIs) as standard management. Such therapy requires that personnel ensure optimal use of these devices. We prospectively evaluated the time required to teach patients correct inhaler use for the emergency treatment of asthma and COPD, and patient factors associated with duration of teaching. DESIGN: MDI arm within a single-center randomized clinical trial comparing bronchodilator administration by MDI with a delivery enhancement device (MDI/DED) vs delivery by wet nebulizer. SETTING: All subjects were treated for asthma or COPD exacerbations at the respiratory acute-care day hospital of the Montreal Chest Institute, immediately after presentation to our emergency department. Inhaler-use education was provided according to a predetermined protocol. MEASUREMENTS: Subjects' baseline characteristics were obtained from medical charts, spirometry, and questionnaires; satisfaction was evaluated by questionnaire. All inhaler-use education was observed and timed. RESULTS: Sixty-one patients with asthma (median age, 46 years) and 32 patients with COPD (median age, 68.5 years) were randomized to treatment by MDI/DED. Mean FEV1 (percent predicted) was 63.5% for patients with asthma and 39.5% for patients with COPD. Five patients could not complete MDI teaching and therefore received subsequent treatment by wet nebulization. For the 88 other patients, the median teaching time was 6.5 min. Shorter teaching-time requirements were independently associated with higher initial arterial oxygen saturation, home DED use after previous MDI instruction, and a single initial bronchodilator treatment by wet nebulization. Most subjects expressed satisfaction with MDI/DED teaching and treatment. CONCLUSIONS: Successful MDI/DED teaching followed by self-medication is feasible in the emergency setting, based on a simple protocol. A single bronchodilator dose administered by wet nebulization may facilitate subsequent MDI teaching.

Acute Disease↗
PubMedDate not supplied

Adjustable maintenance dosing with budesonide/formoterol reduces asthma exacerbations compared with traditional fixed dosing: a five-month multicentre Canadian study.

BACKGROUND: Adjustable maintenance dosing with budesonide/formoterol in a single inhaler (Symbicort, AstraZeneca, Lund, Sweden) may provide a convenient means of maintaining asthma control with the minimum effective medication level. OBJECTIVES: To compare adjustable and fixed maintenance dosing regimens of budesonide/formoterol in asthma. METHODS: This was an open-label, randomized, parallel-group, multicentre, Canadian study of asthma patients (aged 12 years or older, postbronchodilator forced expiratory volume in 1 s 70% or greater of predicted normal). Following a one-month run-in on budesonide/formoterol (100/6 µg or 200/6 µg metered doses, two inhalations twice daily), 995 patients were randomly assigned either to continue on this fixed dosing regimen or to receive budesonide/formoterol adjustable dosing (step down to one inhalation twice daily if symptoms were controlled or temporarily step up to four inhalations twice daily for seven or 14 days if asthma worsened). The primary efficacy variable was the occurrence of exacerbations (requiring oral or inhaled corticosteroids, emergency department treatment, serious adverse events or added maintenance therapy because of asthma). RESULTS: With adjustable dosing, significantly fewer patients experienced exacerbations compared with fixed dosing (4.0% versus 8.9%, P=0.002; number needed to treat=21 [95% CI 13 to 59]). Patients required 36% fewer overall doses of budesonide/formoterol (2.5 versus 3.9 inhalations/day, P<0.001), and total costs per patient were lower (difference over five months -141 Canadian dollars [95% CI -162 Canadian dollars to -116 Canadian dollars]). Asthma symptom severity (modified National Heart, Lung, and Blood Institute stage) was maintained or improved in 97% or greater of patients in both groups (pre-run-in to end of treatment). Both treatments were well tolerated. CONCLUSIONS: Budesonide/formoterol adjustable maintenance dosing provided more effective asthma control than fixed dosing, with a lower overall drug dose and reduced total cost.

Administration, Inhalation↗
PubMedDate not supplied

Adult Asthma Consensus Guidelines update 2003.

BACKGROUND: Several sets of Canadian guidelines for the diagnosis and management of asthma have been published over the past 15 years. Since the last revision of the 1999 Canadian Asthma Consensus Report, important new studies have highlighted the need to incorporate new information into the asthma guidelines. OBJECTIVES: To review the literature on adult asthma management published between January 2000 and June 2003; to evaluate the influence of the new evidence on the recommendations made in the 1999 Canadian Asthma Consensus Guidelines and its 2001 update; and to report new recommendations on adult asthma management. METHODS: Three specific topics for which new evidence affected the previous recommendations were selected for review: initial treatment of asthma, add-on therapies in the treatment of asthma and asthma education. The resultant reviews were discussed in June 2003 at a meeting under the auspices of the Canadian Thoracic Society, and recommendations for adult asthma management were reviewed. RESULTS: The present report emphasises the importance of the early introduction of inhaled corticosteroids in symptomatic patients with mild asthma; stresses the benefit of adding additional therapy, preferably long-acting beta2-agonists, to patients incompletely controlled on low doses of inhaled corticosteroids; and documents the essential role of asthma education. CONCLUSION: The present report generally supports many of the previous recommendations published in the 1999 Canadian Asthma Consensus Report and provides higher levels of evidence for a number of those recommendations.

Adrenal Cortex Hormones↗
PubMedDate not supplied

A population-based evaluation of a regional asthma education centre.

BACKGROUND: A population-based, ecological evaluation was conducted to determine the impact of a regional asthma education centre on reducing asthma-related morbidity and improving the quality of prescribing. METHODS: The number of emergency department (ED) visits for respiratory-related illness and the prescribing of antiasthmatic medications were monitored during consecutive 18-month pre- and postintervention periods in two communities with similar health care resources. Using defined daily doses, the quality of prescribing was assessed by calculating the ratio of inhaled corticosteroids to inhaled, short-acting beta 2-agonists. RESULTS: The reduction in the rate of respiratory-related ED visits in subjects five to 45 years of age was 410 per 10,000 people and 450 per 10,000 people for the intervention and nonintervention communities, respectively. A significant reduction in the rate of ED visits of 698 per 10,000 people was found for patients aged 35 to 45 years in the intervention community (P<0.05). The reduction achieved statistical significance in the nonintervention community in younger patients: 557 per 10,000 people and 567 per 10,000 people for patients aged five to 14 years and 15 to 24 years, respectively (P<0.05). The ratio of inhaled corticosteroids to inhaled beta 2-agonists increased from 0.47 to 0.78 in the intervention community--a 66% change. However, over the course of the preintervention period, the prescribing ratio was already increasing in this community. The corresponding ratios were 0.47 and 0.53 in the nonintervention community--an increase of 13%. CONCLUSIONS: A conclusive association between the establishment of an asthma education centre and changes in health care use or the quality of prescribing could not be demonstrated.

Administration, Inhalation↗
PubMedDate not supplied

Asthma and allergic rhinitis in Quebec children.

BACKGROUND: The Health and Social Survey of Quebec Children and Youth, conducted on representative samples of children nine, 13 and 16 years of age, provided data on the prevalence and determinants of asthma and allergic rhinitis in Quebec. OBJECTIVES: To determine the prevalence of asthma and allergic rhinitis among children in the province of Quebec and to identify the determinants of these pathologies. METHODS: Three groups of more than 1100 children aged nine, 13 and 16 years were recruited. Respiratory symptoms were documented using the International Study of Asthma and Allergies in Childhood questionnaire. Questions enquiring about family income, smoking, degree of urbanization of the child's school's location and various variables related to indoor air were also included. The comparisons of proportions were done using the chi2 test. RESULTS: The prevalence rates for reported history of asthma varied from 14% to 15% depending on the age group. The prevalence of wheezing in the past year was 7% to 8%. Asthma was the primary cause of the limitation of activities due to a health problem in nine- and 13-year-old Quebecers, and the second most common cause in 16-year-old Quebecers. The prevalence of rhinitis, rhinoconjunctivitis and reported history of hay fever increased with age, reaching 28.0%, 15.9% and 21.1%, respectively, in the 16-year-old group. The prevalence of asthma and wheezing was associated with family history and allergies, and inversely related to family income. CONCLUSIONS: The prevalence of childhood asthma is high in the province of Quebec. It is a major cause of the limitation of activities due to a health problem for young Quebecers. A family history of asthma and an atopic predisposition are important determinants in the development of asthma in Quebec.

Adolescent↗
PubMedDate not supplied

The Asthma Quiz for Kidz: a validated tool to appreciate the level of asthma control in children.

BACKGROUND: There is an urgent need to bridge the large gap between optimal and observed asthma control among Canadian children. OBJECTIVES: To adapt the criteria of asthma control proposed in the 1999 Asthma Consensus Statement for children and validate the proposed cut-offs in children with asthma. METHODS: Six clinical criteria of asthma control were phrased as questions and response options, and pretested for clarity. A cross-sectional study was conducted in children one to 17 years of age presenting to the hospital's asthma clinics. Children nine years of age or older and their parents were asked to complete The Asthma Quiz for Kidz separately, and then together, before the medical visit. Parents of younger children completed the questionnaire with their child. Physicians were not informed of the results of the quiz. RESULTS: The mean age of the 343 participants was 8.0+/-4.4 (SD) years with a mean baseline forced expiratory volume in 1 s of 96+/-15% of predicted values. Asthma severity was rated as mild (67%), moderate (29%) or severe (4%). Overall, 57% of subjects endorsed at least two of the six criteria of poor control. The median (interquartile range) Asthma Quiz score was significantly higher when the physician's assessment of asthma control was poor than when the physician's assessment of asthma control was good (3 [1, 5] versus 1 [0, 2], P<0.001), but it did not correlate with the spirometry. A score of at least 2 out of 6 had 73% sensitivity and 59% specificity for identifying poor control. INTERPRETATION: The Asthma Quiz score provides complementary information to, but does not replace, lung function testing. A score of 2 or more out of 6 suggests poor asthma control and should prompt patients to consult their physician for reassessment.

Adolescent↗
PubMedDate not supplied

Rates and patterns of chronic obstructive pulmonary disease exacerbations.

BACKGROUND: Acute exacerbations of chronic obstructive pulmonary disease (COPD) are believed to be a common occurrence in patients with COPD and are known to be associated with considerable morbidity. OBJECTIVE: To describe the frequency of treated COPD exacerbations in a large population-based cohort. SUBJECTS AND METHODS: A cohort of newly treated patients with COPD was formed from the administrative databases of Saskatchewan Health. The outcome was the occurrence of all moderate or severe exacerbations from 1990 to 1999. Exacerbations were defined in three ways: dispensing of a prescription for a systemic antibiotic; dispensing of both a prescription for an antibiotic and a prescription for an oral corticosteroid on the same day; and requiring a hospitalization with a primary discharge diagnosis of COPD. RESULTS: There were 5645 patients who entered the COPD cohort between 1990 and 1997, of whom 4453 experienced at least one exacerbation requiring treatment during follow-up. The overall rate of acute exacerbations was 1.12/person-year. It was constant across all age groups, and was similar in both men and women (1.13/person-year versus 1.11/person-year, respectively). The rate of exacerbations was highest in the first trimester of therapy for the disease (1.39/person-year) and stabilized thereafter at 1.04 exacerbations/person-year. CONCLUSIONS: The results indicate that in a population-based cohort of patients with COPD, the average rate of exacerbations was 1.12/person-year. Men and women had similar rates of exacerbations.

Aged↗
PubMedDate not supplied

Total and specific immunoglobulin E and their relationship to respiratory symptoms in Quebéc children and adolescents.

BACKGROUND: Respiratory disease is a major cause of morbidity in young people. It is now recognized that atopy plays an important role in the development of chronic respiratory symptoms in children. OBJECTIVE: To examine the determinants and consequences of serum total and specific immunoglobulin E (IgE) in a general population sample of Québec children and adolescents. METHODS: In 1999, 2349 children and adolescents (nine, 13 or 16 years of age) who had participated in a respiratory symptom and disease questionnaire had their total IgE measured. Of these participants, a subsample of 451 children and adolescents was analyzed to detect antibodies to eight specific allergens (ie, allergens of dust mites [Dermatophagoides farinae and Dermatophagoides pteronyssinus], cat, dog, ragweed, Timothy grass, mould [alternaria] and cockroach). RESULTS: The geometric mean of the total IgE was 44.4 U/mL among all participants. Concentrations were higher in boys and increased with age. More than 41% of the participants were sensitized to at least one specific allergen. Such sensitization was strongly associated with the occurrence of respiratory conditions and symptoms, namely asthma, wheezing and rhinitis. Family history, school location and ethnic origin had an impact on the prevalence of atopy and total IgE levels. CONCLUSIONS: Allergic sensitization is a major determinant in the development of asthma, wheezing and rhinitis in children and adolescents in the province of Québec.

Adolescent↗
PubMedDate not supplied

Patterns and determinants of compliance with inhaled steroids in adults with asthma.

BACKGROUND: Patient compliance with inhaled corticosteroids (ICS) in asthma is considered to be suboptimal. OBJECTIVES: To describe the patterns of compliance with ICS and identify factors determining the compliance to ICS in adults with asthma. METHODS: Based on a review of the literature and interviews with asthmatic patients who require the regular use of ICS, potential determinants of compliance to ICS were identified. Questionnaires related to these determinants were then administered to a cohort of patients from three subspecialty clinics, including two from university-affiliated centres. Patients with mild-to-moderate asthma who were 15 years of age and older and required (from the physician's point of view) ICS as maintenance medication because of persistent asthma were included in the study. Patients were followed for a period of 12 weeks. Compliance was measured using electronic devices. RESULTS: Data from 124 patients (51 men; mean age 47+/-15 years; mean prescribed daily dose of ICS [fluticasone propionate] 643+/-385 microg) were analyzed. On average, the patients took 72+/-24% of their prescription. Four patterns of compliance were observed and are described: 1A -- regular compliance (n = 29); 1B -- irregular compliance (n = 37); 2A -- regular noncompliance (n = 24); and 2B -- irregular noncompliance (n = 34). Among the potential predictors of noncompliance, age was the only significant predictor (compliance increased with increasing age). There was no difference in asthma control between compliant and noncompliant patients. CONCLUSION: Compliance to ICS in patients with asthma is often suboptimal and difficult to predict. The observations suggest that some asthmatics may be overtreated with ICS.

Administration, Inhalation↗