Concepts of asthma severity and control are important in the evaluation of patients and their response to treatment but the terminology is not standardised and the terms are often used interchangeably. This review, arising from the work of an American Thoracic Society/European Respiratory Society Task Force, identifies the need for separate concepts of control and severity, describes their evolution in asthma guidelines and provides a framework for understanding the relationship between current concepts of asthma phenotype, severity and control.''Asthma control'' refers to the extent to which the manifestations of asthma have been reduced or removed by treatment. Its assessment should incorporate the dual components of current clinical control (e.g. symptoms, reliever use and lung function) and future risk (e.g. exacerbations and lung function decline).The most clinically useful concept of asthma severity is based on the intensity of treatment required to achieve good asthma control, i.e. severity is assessed during treatment. Severe asthma is defined as the requirement for (not necessarily just prescription or use of) highintensity treatment. Asthma severity may be influenced by the underlying disease activity and by the patient's phenotype, both of which may be further described using pathological and physiological markers. These markers can also act as surrogate measures for future risk.
Telephone surveys describing suboptimal asthma control may be biased by low response rates.In order to obtain an unbiased assessment of asthma control and assess its impact in primary care, primary care physicians used a 1-page control questionnaire in 50 consecutive asthma patients.Of the 10,428 patients assessed by 354 physicians, 59% were uncontrolled, 19% well-controlled and 23% totally controlled. Physicians overestimated control, regarding only 42% of patients as uncontrolled. Physicians were more likely to report plans to alter the regimens of uncontrolled patients than controlled patients (1.29 versus 0.20 medication changes per patient) doing so in a fashion consistent with guideline recommendations. Of the uncontrolled patients, 59% required one or more urgent care or specialist visits versus 26 and 15% of well-controlled or totally controlled patients, respectively. Patients were more likely to report short-term symptom control when they had not required urgent or specialist care (odds ratio 5.68; 95% confidence interval 4.91-6.58).The majority of asthma patients treated in general practice are uncontrolled. Lack of control can be recognised by physicians who are likely to consider appropriate changes to therapy. A lack of short-term symptom control of asthma is associated with excess healthcare utilisation.
Endurance athletes show an increased prevalence of airway hyperresponsiveness. The aim of the present study was to evaluate the long-term effects of training on airway responsiveness, inflammation and epithelial damage in swimmers and cold-air athletes.In total, 64 elite athletes (32 swimmers and 32 cold-air athletes), 32 mild asthmatic subjects and 32 healthy controls underwent allergy skin prick testing, methacholine challenge and induced sputum analysis.Overall, 69% of swimmers and 28% of cold-air athletes had airway hyperresponsiveness. Sputum neutrophil count correlated with the number of training hours per week in both swimmers and cold-air athletes. Eosinophil counts were higher in swimmers than in healthy subjects, although they were lower than in asthmatic subjects, and correlated with airway hyperresponsiveness in swimmers only. The eosinophil count in cold-air athletes was similar to that in healthy subjects. Bronchial epithelial cell count was not correlated with airway hyperresponsiveness but was significantly increased in swimmers, compared with healthy and asthmatic controls.In conclusion, the present authors observed significant airway inflammation only in competitive athletes with airway hyperresponsiveness. However, the majority of elite athletes showed evidence of bronchial epithelial damage that could possibly contribute to the development of airway hyperresponsiveness.
To determine whether asthmatic subjects have an increase in airway wall thickness that could enhance airway narrowing during bronchoprovocation, we examined the relationship between airway responsiveness and bronchial wall thickness measured by high-resolution computed tomography (HRCT). We studied 24 nonsmokers with asthma, of whom 13 had a fixed component of airflow obstruction (Group 1) and 11 had an optimal FEV1 of 80% or more of the predicted value (Group 2). These subjects were compared with a control group of 10 nonasthmatic subjects (Group 3). Measurements were taken of each subject's expiratory flows, bronchodilator response, lung volumes, and methacholine responsiveness. All subjects used an inhaled beta 2-agonist on demand, and 19 also used inhaled steroids (13 in a Group 1 and six in Group 2). HRCT sections were obtained at the top and base of the lung and at the level of the intermediary bronchus (IB), although only this last level was found adequate for analysis. The ratio of IB wall thickness to outer diameter (T/D) showed a negative relationship with the outer diameter in Group 1 only. The mean T/D ratio of IB was not significantly different in Groups 1, 2, and 3, with respective values of 0.16 +/- 0.01, 0.15 +/- 0.01, and 0.18 +/- 0.01 at TLC, and 0.16 +/- 0.01, 0.20 +/- 0.01, and 0.19 +/- 0.01 at FRC. In subjects with a fixed component of airflow obstruction, the thicker the airway wall in relation to its diameter, the lower was the PC20 for methacholine. This was not observed in the other study groups. No correlation was found between the T/D ratio and baseline FEV1.(ABSTRACT TRUNCATED AT 250 WORDS)
The objective of the present document is to review the impact of new information on the recommendations made in the last (1999) Canadian Asthma Consensus Guidelines. It includes relevant published studies and observations or comments regarding what are considered to be the main issues in asthma management in children and adults in office, emergency department, hospital and clinical settings. Asthma is still insufficiently controlled in a large number of patients, and practice guidelines need to be integrated better with current care. This report re-emphasises the need for the following: objective measures of airflow obstruction to confirm the diagnosis of asthma suggested by the clinical evaluation; identification of contributing factors; and the establishment of a treatment plan to rapidly obtain and maintain optimal asthma control according to specific criteria. Recent publications support the essential role of asthma education and environmental control in asthma management. They further support the role of inhaled corticosteroids as the mainstay of anti-inflammatory therapy of asthma, and of both long acting beta2-agonists and leukotriene antagonists as effective means to improve asthma control when inhaled corticosteroids are insufficient. New developments, such as combination therapy, and recent major trials, such as the Children's Asthma Management Project (CAMP) study, are discussed.
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