Differences in trigger factors and symptoms between patients with asthma-like symptoms and patients with asthma: development of a basis for a questionnaire

Assessment of asthma severity in adults with ever asthma: A continuous score

BACKGROUND

In epidemiological studies, continuous measures of asthma severity should be used to catch the heterogeneity of phenotypes. This study aimed at developing and validating continuous measures of asthma severity in adult patients with ever asthma from the general population, to be used in epidemiological studies.

METHODS

Respiratory symptoms, anti-asthmatic treatment and lung function were measured on 520 patients with ever asthma aged 20-64 years from the general Italian population (GEIRD study; 2007/2010). The variables that represent the same dimension of asthma severity were identified through an exploratory factor analysis and were summarized through a multiple factor analysis.

RESULTS

Only respiratory symptoms and anti-asthmatic treatment were summarized in a continuous score (STS). STS ranges from 0 (no symptoms/treatment) to 10 (maximum symptom frequency and treatment intensity). STS was positively correlated with the Global Initiative for Asthma classification of asthma severity computed on the 137 cases with a doctor's diagnosis (Spearman's coefficient = 0.61, p-value<0.0001) (concurrent validity). Furthermore, using a cohort of 1,097 European asthmatics (ECRHS II study; 1999/2002), increasing STS levels at baseline (1991/1993) were positively associated with long-term outcomes (hospitalization and lost workdays for breathing problems, asthma attack frequency and use of asthma controllers) (predictive validity). Finally, the STS scores computed from the GEIRD and ECRHS II data were comparable (Lin's coefficient = 0.95, p-value<0.0001) (replication analysis).

CONCLUSIONS

STS is a valid and replicable measure of asthma severity in adults, which could be used in association studies.

Dissociation of dysfunctional breathing and odour intolerance among adults in a general-population study

BACKGROUND

Many patients present with a mixture of respiratory problems such as shortness of breath, heavy breathing, coughing and odour intolerance. If these patients are diagnosed as asthma, it might sometimes be a false diagnosis. Concepts such as sensory hyperreactivity, hyperventilation, asthma-like symptoms, odour intolerance and dysfunctional breathing are used to refer to these patients. Non-respiratory symptoms such as headache, fatigue and bloating are sometimes also part of the clinical picture. Our aim was to use factor analysis to increase our understanding of breathing-related symptoms in a general-population frame.

METHODS

A respiratory questionnaire was answered by 10 108 subjects in a general-population sample. Items aiming to identify individuals with breathing-related symptoms and asthma were included. We used factor analysis with Varimax rotation to extract discriminatory components (i.e. groups of symptoms), based on the questionnaire items. The aim was to find groups of items (factors) as distinct as possible, still allowing overlap and showing the importance of each item in the separated factor.

RESULTS

Five distinct factors were identified in the factor analysis, representing dysfunctional breathing, odour intolerance, asthma, bronchitis and a group with mixed symptoms, respectively. These five factors explained 55% of the variance.

CONCLUSIONS

Based on our findings, we conclude that non-asthmatic breathing-related symptoms may be separated into at least two categories in a general population, odour intolerance and dysfunctional breathing. These two categories seem to be two distinct groups of subjects with breathing-related symptoms and may represent different clinical entities separated from asthma and bronchitis.

Diagnosis of asthma - new theories

INTRODUCTION

Recent studies have shown a remarkably high frequency of poorly controlled asthma. Several reasons for this treatment failure have been discussed, however, the basic question of whether the diagnosis is always correct has not been considered. Follow-up studies have shown that in many patients asthma cannot be verified despite ongoing symptoms. Mechanisms other than bronchial obstruction may therefore be responsible. The current definition of asthma may also include symptoms that are related to mechanisms other than bronchial obstruction, the clinical hallmark of asthma.

AIM

Based on a review of the four cornerstones of asthma - inflammation, hyperresponsiveness, bronchial obstruction and symptoms - the aim was to present some new aspects and suggestions related to the diagnosis of adult non-allergic asthma.

CONCLUSION

Recent studies have indicated that "classic" asthma may sometimes be confused with asthma-like disorders such as airway sensory hyperreactivity, small airways disease, dysfunctional breathing, non-obstructive dyspnea, hyperventilation and vocal cord dysfunction. This confusion may be one explanation for the high proportion of misdiagnosis and treatment failure. The current diagnosis, focusing on bronchial obstruction, may be too "narrow". As there may be common mechanisms a broadening to include also non-obstructive disorders, forming an asthma syndrome, is suggested. Such broadening requires additional diagnostic steps, such as qualitative studies with analysis of reported symptoms, non-effort demanding methods for determining lung function, capsaicin test for revealing airway sensory hyperreactivity, careful evaluation of the therapeutic as well as diagnostic effect of corticosteroids and testing of suggested theories.

Diagnosis of asthma in primary health care: a pilot study

Some patients with an asthma diagnosis have a poor controlled asthma. One explanation may be an incorrect diagnosis. Aim. The aim of the study was to diagnose and classify patients with non-infectious lower respiratory tract problems in primary health care using internationally applied diagnostic criteria and diagnostic tests. Patients and Methods. New adult patients visiting a primary health care centre due to lower airway problems were included. The diagnostic tests included FEV₁, FVC, PEF, two questionnaires, methacholine test, and skin prick test. Results. The patients (n = 43) could be divided into four groups: asthma (28%), asthma-like disorder (44%), idiopathic cough (12%), and a nonreversible bronchial obstructive group (16%). The asthma and asthma-like groups showed similar patterns of airway symptoms and trigger factors, not significantly separated by a special questionnaire. Phlegm, heavy breathing, chest pressure/pain, cough, and wheezing were the most common symptoms. Physical exercise and scents were the dominating trigger factors. Conclusions. Nonobstructive asthma-like symptoms seem to be as common as bronchial asthma in primary health care. Due to the similarities in symptoms and trigger factors the study supports the hypothesis that asthma and nonobstructive asthma-like disorders are integrated in the same “asthma syndrome,” including different mechanisms, not only bronchial obstruction.

What do we know about asthma triggers? a review of the literature

OBJECTIVE

For patients with asthma, exacerbations and poor control can result from exposure to environmental triggers, such as allergens and air particulates. This study reviewed the international literature to determine whether a global checklist of common asthma triggers might be feasible for use as a research or management tool in clinical practice.

METHODS

Literature published from 2002 to 2012 was identified through PubMed and EMBASE using the following search terms: asthma, asthma triggers, prevalence, among others. A total of 1046 abstracts were found; 85 articles were reviewed covering six continents (number of articles): Africa (1), Asia (22), Australia (1), Europe (27), North America (22), and South America (4).

RESULTS

The literature consistently pointed to asthma triggers as one contributor to poor asthma control. Frequently cited triggers were similar across countries/regions and included allergens (particularly pollens, molds, dust, and pet dander), tobacco smoke, exercise, air pollutants/particulates, weather patterns/changes, and respiratory infections. Definitions of asthma triggers, how triggers are taken into account in definitions of asthma control, and scientific inquiry into optimal management techniques for triggers were inconsistent and sparse.

CONCLUSIONS

Given the apparent importance of triggers in attaining and maintaining asthma control, empirical research concerning optimal trigger management is needed. Results demonstrate that asthma triggers are similar across continents, suggesting a global checklist of triggers for use in research and clinical practice would be feasible.

Diagnosis of asthma - a new approach

Current definition of asthma involves four cornerstones: inflammation, hyperresponsiveness, bronchoconstriction, and symptoms. In research, the symptoms have had the slightest attention. According to international guidelines, the asthma symptoms are episodic breathlessness, wheeze, cough, tightness of the chest, and shortness of breath. As there are several symptoms, a primary question is how they are related to bronchoconstriction, the main clinical feature of asthma. Symptoms and lung function tests are regularly used for the evaluation of clinical health status and effect of treatment. However, there is no or poor correlation between these two variables, which means that they represent different mechanisms. Reduced lung function, such as a low FEV(1) , represents bronchial constriction, what do the symptoms represent? Some symptoms such as breathlessness and shortness of breath seem not to be evidence-based asthma symptoms. Focusing on bronchial obstruction is important in view of the potential risk of asthma attacks, but nonobstructive symptoms occur frequently and may also cause severe discomfort and poor quality of life. Interpreting all symptoms as signs of bronchoconstriction (asthma) may lead to misinterpretation when assessing health status and effect of treatment. Although a 'soft' variable, the strength of symptoms is that they are representing various mechanisms. The physiological preconditions for control and defense of respiration must be considered in the diagnostic process, regardless of inflammation, allergy, psychology, or other etiological factors. Based on studies on dyspnea in cardiopulmonary diseases, including asthma and asthma-like disorders, there seems to be a continuous spectrum of symptoms and mechanisms integrated in a single asthma syndrome.