Distinguishing asthma and chronic obstructive pulmonary disease: why, why not and how?

In Which the Gain is more from Pulmonary Rehabilitation? Asthma or COPD?

OBJECTIVES

Pulmonary rehabilitation (PR) is useful for patients with chronic obstructive pulmonary disease (COPD) but not clear for patients with asthma. The aim of the present study was to evaluate the effectiveness of PR in patients with asthma by comparing patients with COPD. The study was designed as a retrospective case series. We recruited patients with COPD and asthma.

MATERIALS AND METHODS

Demographics, respiratory symptoms, medications, smoking history, comorbidities, exercise capacity, respiratory function tests, and quality of life (QOL) were recorded. Exercise capacity was evaluated by the 6-minute walk test (6MWT), QOL with St. George's Respiratory Questionnaire (SGRQ), 36-item Short Form Health Survey (SF-36) Quality of Life Questionnaire, and Hospital Anxiety and Depression (HAD) Scale.

RESULTS

Forty-two patients with asthma and 25 COPD who completed PR were included in the study. There was no difference in terms of age and sex between the groups (p=0.100 and p=0.365, respectively); however, body mass index was higher in the asthmatic group (p=0.007). Partial oxygen pressure (pO₂) difference and arterial oxygen saturation (SpO₂) difference were significantly higher in the COPD group than in the asthma group after PR (p<0.05). When the patients were compared before and after PR in both groups, a significant increase was detected in exercise capacity and QOL (6MWT, HADa, SGRQ, and SF-36 in all domains) (p<0.05). When two groups are contrasted according to the difference between pre- and post-PR of variables, there was no significant difference except pO₂, SpO₂, and Medical Research Council (p>0.05).

CONCLUSION

Physicians refer patients with COPD to PR; however, patients with asthma are not generally referred to the same frequency. We would like to emphasize that PR may be as effective as COPD in asthma.

Asthma and COPD: Similarities and Differences in the Pathophysiology, Diagnosis and Therapy

Asthma and chronic obstructive pulmonary disease (COPD) are two of the most common chronic lung diseases worldwide. Distinguishing between these different pulmonary diseases can be difficult in practice because of symptomatic similarities. A definitive diagnosis is essential for correct treatment. This review article presents the different symptoms of these two chronic inflammatory lung diseases following a selective search of the PubMed database for relevant literature published between 1996 and 2012. While cough occurs in both diseases, asthmatics often have a dry cough mainly at night, which is often associated with allergies. In contrast, COPD is usually caused by years of smoking. Paroxysmal dyspnea, which occurs in asthma, is characterized by shortness of breath, while in COPD it occurs during physical exertion in early stages and at rest in later stages of the disease. Asthma often begins in childhood or adolescence, whereas COPD occurs mainly in smokers in later life. It is possible to live with asthma into old age, whereas the life expectancy of patients with COPD is significantly limited. Currently, there is no general curative treatment for either disorder.

Novel therapeutic strategies for lung disorders associated with airway remodelling and fibrosis

Inflammatory cell infiltration, cytokine release, epithelial damage, airway/lung remodelling and fibrosis are central features of inflammatory lung disorders, which include asthma, chronic obstructive pulmonary disease, acute respiratory distress syndrome and idiopathic pulmonary fibrosis. Although the lung has some ability to repair itself from acute injury, in the presence of ongoing pathological stimuli and/or insults that lead to chronic disease, it no longer retains the capacity to heal, resulting in fibrosis, the final common pathway that causes an irreversible loss of lung function. Despite inflammation, genetic predisposition/factors, epithelial-mesenchymal transition and mechanotransduction being able to independently contribute to airway remodelling and fibrosis, current therapies for inflammatory lung diseases are limited by their ability to only target the inflammatory component of the disease without having any marked effects on remodelling (epithelial damage and fibrosis) that can cause lung dysfunction independently of inflammation. Furthermore, as subsets of patients suffering from these diseases are resistant to currently available therapies (such as corticosteroids), novel therapeutic approaches are required to combat all aspects of disease pathology. This review discusses emerging therapeutic approaches, such as trefoil factors, relaxin, histone deacetylase inhibitors and stem cells, amongst others that have been able to target airway inflammation and airway remodelling while improving related lung dysfunction. A better understanding of the mode of action of these therapies and their possible combined effects may lead to the identification of their clinical potential in the setting of lung disease, either as adjunct or alternative therapies to currently available treatments.

Visual analog scale as a predictor of GINA-defined asthma control. The SACRA study in Japan

OBJECTIVE

The assessment of asthma control is pivotal to treatment decisions. A questionnaire that assesses the Global Initiative for Asthma (GINA)-defined control requires four questions. A visual analog scale (VAS) to evaluate asthma control can be simply marked, but its correlation with GINA-defined control has been insufficiently evaluated. The purpose of this study is to evaluate whether VAS levels can predict GINA-defined asthma control with particular emphasis on the distinctions between "partly controlled" and "uncontrolled" and between "partly controlled" and "controlled" asthma,

METHODS

A cross-sectional multicenter study was carried out throughout Japan (SACRA) from March to August 2009 among patients with a diagnosis and treatment of asthma. Asthma control was studied using the GINA questionnaire and a VAS measurement of asthma severity. Pulmonary function testing was not carried out,

RESULTS

1910 physicians enrolled 29,518 patients with asthma. 15,051 (51.0%) questionnaires were administered by physicians; patients filled out 14,076 (47.7%) questionnaires themselves. 28,225 (95.6%) of the patients were evaluable. VAS measurement of asthma symptoms was useful in predicting levels of GINA-defined control categories (the area under the receiver operating characteristic curve ranging from 0.704 to 0.837). Patients with "controlled," "partly controlled," and "uncontrolled" asthma were discriminated by VAS levels (1.50, 4.79, and 7.19). Similar results have been obtained with self- and physician-administered questionnaires showing the validity of results.

CONCLUSION

Measurement of VAS levels is able to discriminate between patients with "controlled," "partly controlled," and "uncontrolled" asthma. The VAS score could be a simple guide in clinical situations requiring daily or regular evaluation of asthma control.

Intakes of long-chain omega-3 (n-3) PUFAs and fish in relation to incidence of asthma among American young adults: the CARDIA study

BACKGROUND

Although long-chain ω-3 (n-3) PUFAs (LCω3PUFAs) have been linked to the prevention of some inflammatory disorders, little is known about the association between these fatty acids and incidence of asthma.

OBJECTIVE

The objective was to prospectively investigate the association between LCω3PUFAs and fish intake and incidence of asthma among American young adults.

DESIGN

A 20-y follow-up longitudinal analysis was conducted in a biracial cohort of 4162 Americans, aged 18-30 y, with a history of asthma at baseline in 1985. Diet was assessed by a validated interviewer-administered quantitative food-frequency questionnaire at the examinations in 1985, 1992, and 2005. Incident self-reported asthma was defined as having a physician diagnosis of asthma and/or the use of asthma medications between 1985 and 2005.

RESULTS

During the 20-y follow-up, 446 incident cases of asthma were identified. LCω3PUFA intake was significantly inversely associated with incidence of asthma after adjustment for sociodemographic, major lifestyle, and dietary confounders. The multivariable-adjusted HR for the highest quintile of LCω3PUFA intake as compared with the lowest quintile was 0.46 (95% CI: 0.33, 0.64; P-trend < 0.01). However, a higher frequency of nonfried fish consumption was not significantly associated with the risk of asthma. DHA showed a greater inverse association than did EPA. The association between LCω3PUFAs and incident asthma was not appreciably modified by sex, race, BMI, smoking status, or atopic status.

CONCLUSION

This study showed that intakes of LCω3PUFAs are inversely longitudinally associated with the incidence of asthma in American young adults.

The Asthma-COPD Overlap Syndrome: A Common Clinical Problem in the Elderly

Many patients with breathlessness and chronic obstructive lung disease are diagnosed with either asthma, COPD, or—frequently—mixed disease. More commonly, patients with uncharacterized breathlessness are treated with therapies that target asthma and COPD rather than one of these diseases. This common practice represents the difficulty in distinguishing these disorders clinically, particularly in patients with a history that does not easily differentiate asthma from COPD. A common clinical scenario is an older former smoker with partially reversible or fixed airflow obstruction and evidence of atopy, demonstrating “overlap” features of asthma and COPD. We stress that asthma-COPD overlap syndrome becomes more prevalent with advancing age as patients respond less favorably to guideline-recommended drug therapy. We review the similarities and differences in clinical characteristics between these disorders, and their physiologic and inflammatory profiles within the context of the aging patient. We underscore the difficulties in differentiating asthma from COPD in current or former smokers, share our institutional experience with overlap syndrome, and highlight the need for new research to better characterize and investigate this important clinical phenotype.

Mortality in Western Australian seniors with chronic respiratory diseases: a cohort study

Background

Relatively few studies have examined survival by pharmacotherapy level and the effects of patient characteristics on mortality by pharmacotherapy level in older chronic respiratory disease (CRD) patients. This study aimed to investigate these issues in older (≥ 65) CRD patients in Western Australia.

Methods

We identified 108,312 patients ≥ 65 years with CRD during 1992-2006 using linked medical, pharmaceutical, hospital and mortality databases held by the Commonwealth and State governments. Pharmacotherapy classification levels were designed by a clinical consensus panel. Cox regression was used to investigate the study aim.

Results

Patients using only short acting bronchodilators experienced similar, but slightly worse survival than patients in the highest pharmacotherapy level group using high dose inhaled corticosteroids (ICS) ± long acting bronchodilators (LABs) ± oral steroids. Patients using low to medium dose ICS ± LABs experienced relatively better survival. Also, male gender was associated with all-cause mortality in all patients (HR = 1.72, 95% CI 1.65-1.80) and especially in those in the highest pharmacotherapy level group (HR = 1.97, 95%CI = 1.84-2.10). The P-value of interaction between gender and pharmacotherapy level for the effect on all-cause death was significant (0.0003).

Conclusions

Older patients with CRD not using ICS experienced the worst survival in this study and may benefit from an escalation in therapeutic regime. Males had a higher risk of death than females, which was more pronounced in the highest pharmacotherapy level group. Hence, primary health care should more actively direct disease management to mild-to-moderate disease patients.

Respiratory hospital admissions were associated with ambient airborne pollen in Darwin, Australia, 2004-2005

BACKGROUND

Although the role of pollen and fungus in specific allergic disorders has been well established, the public health impacts of ambient concentrations of airborne pollen and fungal spores; the shapes of concentration-response relationships; and the relative effects of different taxa are gaps in current knowledge.

OBJECTIVE

To investigate associations between daily average ambient pollen and fungal spore concentrations with hospital admissions for total respiratory diseases; asthma; chronic obstructive pulmonary disease (COPD); and respiratory infections in Darwin, Australia, during the period from April 2004 to November 2005.

METHODS

We assessed these relationships in a two-stage modelling approach designed to quantify potential non-linear relationships. First, generalized additive models determined the shapes of concentration-response relationships. Second, linear associations were examined using generalized linear models. Non-linear relationships were analysed by categorizing pollen and fungal spore concentrations based on their distributions.

RESULTS

Positive linear associations were found between total pollen concentrations and hospital admissions for total respiratory diseases and COPD. While our exploratory first-stage analysis suggested non-linear relationships for total pollen with asthma and respiratory infections, no convincing evidence for these relationships was found in the second-stage analysis. When individual taxa were investigated, associations were the strongest in relation to Myrtaceae pollen (the dominant tree taxa in the region), while positive associations not attaining statistical significance were observed for Poaceae, Cyperaceae and Arecaceae. No associations were evident for any conditions with fungal spores.

CONCLUSIONS

Our finding of an association between pollen count and respiratory hospital admissions that could not be explained by asthma admissions suggests that ambient airborne pollens might have a wider public health impact than previously recognized.