Estimating the prevalence of COPD in Canada: Reported diagnosis versus measured airflow obstruction.

BACKGROUND: Estimates of chronic obstructive pulmonary disease (COPD) prevalence based on self-reports of a diagnosis are thought to underestimate the prevalence of COPD in Canada. DATA AND METHODS: Pre-bronchodilator spirometry measures were obtained from the 2007 to 2009 Canadian Health Measures Survey for 2,487 individuals aged 35 to 79. The prevalence of self-reported chronic bronchitis symptoms and self-reported diagnosis of COPD by a health care professional was compared with the prevalence of measured airflow obstruction according to seven definitions, including the Global Initiative for Obstructive Lung Disease (GOLD) criteria. RESULTS: The prevalence of measured airflow obstruction compatible with COPD was two to six times greater than estimates based on self-reports of a diagnosis. An estimated 16.6% (95% CI: 14.3%-18.9%) of people aged 35 to 79 had pre-bronchodilator airflow obstruction as defined by ≥ GOLD stage I, and 8.1% (95% CI: 6.0%-10.2%) had ≥ GOLD stage II. INTERPRETATION: This study suggests that the prevalence of COPD in Canada has been underestimated.

Airflow obstruction in young adults in Canada.

OBJECTIVE: Airflow obstruction is relatively uncommon in young adults, and may indicate potential for the development of progressive disease. The objective of the present study was to enumerate and characterize airflow obstruction in a random sample of Canadians aged 20 to 44 years. SETTING: The sample (n=2962) was drawn from six Canadian sites. DESIGN: A prevalence study using the European Community Respiratory Health Survey protocol was conducted. Airflow obstruction was assessed by spirometry. Bronchial responsiveness, skin reactivity to allergens and total serum immunoglobulin E were also measured. Logistic regression was used for analysis. RESULTS: Airflow obstruction was observed in 6.4% of the sample, not associated with sex or age. The risk of airflow obstruction increased in patients who had smoked and in patients who had lung trouble during childhood. Adjusted for smoking, the risk of airflow obstruction was elevated for subjects with past and current asthma, skin reactivity to allergens, elevated levels of total immunoglobulin E and bronchial hyper-responsiveness. Of the subjects with airflow obstruction, 21% were smokers with a history of asthma, 50% were smokers without asthma, 12% were nonsmokers with asthma and 17% were nonsmokers with no history of asthma. Bronchial hyper-responsiveness increased the prevalence of airflow obstruction in each of these groups. CONCLUSION: Smoking and asthma, jointly and individually, are major determinants of obstructive disorders in young adults. Bronchial hyper-responsiveness contributes to obstruction in both groups.

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.

Sore throat progressing to embolic sepsis: a case of Lemierre's syndrome.

Lemierre's syndrome is a rare clinical syndrome defined as orophyngeal sepsis, thrombophlebitis of the internal jugular vein and septic thombo-emboli. It is typically encountered in young, immunocompetent individuals, with a mean incident age of 20 years. The organism that is most commonly associated is an anaerobic Gram-negative bacterium: Fusobacterium species. The defined treatment course is at least six weeks of antibiotics, with the role of anticoagulation being unclear. The present article documents a case of Lemierre's syndrome complicated by acute renal failure and loculated pleural effusion in an otherwise healthy 16-year-old patient.

Implementing practice guidelines: a workshop on guidelines dissemination and implementation with a focus on asthma and COPD.

The present supplement summarizes the proceedings of the symposium "Implementing practice guidelines: A workshop on guidelines dissemination and implementation with a focus on asthma and COPD", which took place in Quebec City, Quebec, from April 14 to 16, 2005. This international symposium was a joint initiative of the Laval University Office of Continuing Medical Education (Bureau de la Formation Médicale Continue), the Canadian Thoracic Society and the Canadian Network for Asthma Care, and was supported by many other organizations and by industrial partners. The objectives of this meeting were to examine the optimal implementation of practice guidelines, review current initiatives for the implementation of asthma and chronic obstructive pulmonary disease (COPD) guidelines in Canada and in the rest of the world, and develop an optimal strategy for future guideline implementation. An impressive group of scientists, physicians and other health care providers, as well as policy makers and representatives of patients' associations, the pharmaceutical industry, research and health networks, and communications specialists, conveyed their perspectives on how to achieve these goals. This important event provided a unique opportunity for all participants to discuss key issues in improving the care of patients with asthma and COPD. These two diseases are responsible for an enormous human and socioeconomic burden around the world. Many reports have indicated that current evidence-based guidelines are underused by physicians and others, and that there are many barriers to an effective translation of recommendations into day-to-day care. There is therefore a need to develop more effective ways to communicate key information to both caregivers and patients, and to promote appropriate health behaviours. This symposium contributed to the initiation of what could become the "Canadian Asthma and COPD Campaign", aimed at improving care and, hence, the quality of life of those suffering from these diseases. It is hoped that this event will be followed by other meetings that focus on how to improve the transfer of key recommendations from evidence-based guidelines into current care, and how to stimulate research to accomplish this.

Are questionnaires on respiratory symptoms reliable predictors of airway hyperresponsiveness in athletes and sedentary subjects?

This study aimed at determining the frequency of respiratory symptoms in high-level athletes and whether respiratory questionnaires are reliable predictors of airway hyperresponsiveness (AHR) in this population compared with control subjects. One hundred high-level athletes exercising in different conditions of ambient air (dry, humid, cold or mixed dry and humid) and 50 sedentary control subjects answered four question sets on exercise-induced symptoms of postnasal drip (Q1), breathlessness, chest tightness and wheezing (Q2), and cough (Q3). Another question set (Q4) evaluated the self-description of nociceptive sensations associated with respiratory symptoms. Methacholine inhalation tests were performed in all subjects to obtain a 20% fall in forced expiratory volume in 1 second (PC20). AHR could be detected by questionnaires in 37 of 44 (84%) subjects with a PC20 < 8 mg/mL. Sensitivity to detect AHR varied between the different subgroups of athletes with each of the question sets; however, no significant differences in sensitivity were observed between the groups of athletes and controls except for Q3 (P=.007), in which athletes exercising in cold air reported more exercise-induced cough. Q2 had a better specificity (83%) than Q3 (77%) and Q4 (64%). Combined question sets revealed that three swimmers, two triathletes, and two controls, who answered negatively to all question sets, had a PC20 < 8 mg/mL. Questionnaires on symptoms and on associated nociceptive sensations may help to detect AHR as well in athletes and controls, although for some subgroups of athletes such as swimmers and triathletes and in some controls, false negative questionnaires can be observed and AHR underreported.

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.