Most difficult asthma originates primarily in adult life

Prognosis of new-onset asthma diagnosed at adult age

BACKGROUND

Asthma is a common chronic disease, which can affect patients at any age. Recently, cluster analyses have suggested that patients with asthma can be divided into different phenotypes and that the age at the onset of the disease is a critical defining factor. The prognosis of allergic childhood-onset asthma is relatively well known, whereas the prognosis of adult-onset asthma remains unclear.

METHODS

We undertook a systematic review to identify studies that evaluated the long-term prognosis of new-onset asthma diagnosed at adult age. Criteria used (set 1) were: 1. adult-onset asthma, 2. physician diagnosed asthma (including objective lung-functions) < 1 year before the first visit, 3. follow-up time of at least 5 years, 4. objective lung function measurements used at follow-up and 5. not a comparative trial. Another set of studies (set 2) with less strict criteria were gathered.

RESULTS

The main result of this systematic review is that the amount of evidence on the prognosis of new-onset asthma diagnosed at adult age is very limited. Only one study (n = 250) fulfilled the criteria (set 1) and it suggests that the five-year prognosis of new-onset asthma diagnosed at adult age may not be favorable, the proportion of patients being in remission was less than 5%. Furthermore, six additional follow-up studies (n = 964) were identified including mainly patients with adult-onset asthma (set 2). These studies had variable endpoints and the results could not be combined.

CONCLUSION

Further follow-up studies that recruit patients with new-onset adult asthma are needed to understand the prognostic factors in adult-onset asthma.

Adult-onset asthma becomes the dominant phenotype among women by age 40 years. the longitudinal CARDIA study

RATIONALE

Although asthma is usually considered to originate in childhood, adult-onset disease is being increasingly reported.

OBJECTIVES

To contrast the proportion and natural history of adult-onset versus pediatric-onset asthma in a community-based cohort. We hypothesized that asthma in women is predominantly of adult onset rather than of pediatric onset.

METHODS

This study used data from the Coronary Artery Risk Development in Young Adults (CARDIA) cohort in the United States over a 25-year period. Adult- and pediatric-onset asthma phenotypes were studied, as defined by age at onset of 18 years or older. Subjects with asthma were categorized by sex, obesity, atopy, smoking, and race by mean age/examination year, using a three-way analysis of covariance model. Natural history of disease was examined using probabilities derived from a Markov chain model.

MEASUREMENTS AND MAIN RESULTS

Asthma of adult onset became the dominant (i.e., exceeded 50%) phenotype in women by age 40 years. The age by which adult-onset asthma became the dominant phenotype was further lowered for obese, nonatopic, ever-smoking, or white women. The prevalence trend with increasing time for adult-onset disease was greater among subjects with nonatopic than atopic asthma among both sexes. Furthermore, adult-onset asthma had remarkable sex-related differences in risk factors. In both sexes, the quiescent state for adult-onset asthma was less frequent and also "less stable" over time than for pediatric-onset asthma.

CONCLUSIONS

Using a large national cohort, this study challenges the dictum that most asthma in adults originates in childhood. Studies of the differences between pediatric- and adult-onset asthma may provide greater insight into the phenotypic heterogeneity of asthma.

Phenotype properties and status of corticosteroid resistance among patients with uncontrolled asthma

BACKGROUND

Control cannot be achieved in some asthmatics although optimal monitoring and treatment is administered. Glucocorticoid (GC) resistance is one of the reasons of poor asthma control. We aimed to investigate GC resistance by lymphocyte proliferation suppression test (LPST) in uncontrolled asthmatics.

METHODS

After assessing asthma control level of 77 asthmatics their treatment was adjusted upon GINA guidelines. They were followed-up for three to six months and the patients who remained uncontrolled were accepted as uncontrolled patients. Steroid resistance test (SRT) was applied to them (7-14 days oral prednisolone) and the patients who were still uncontrolled and/or had a FEV1 increase <15% after SRT were assessed as the "case group" while the remaining composed the "control group". Optimal treatment was adjusted and at the end of a follow-up period LPST was performed to both groups.

RESULTS

Fourteen of the case (n=22) and four (n=8) of the control groups could be evaluated by LPST. Proliferated lymphocytes were observed to be significantly suppressed in all dexamethasone concentrations in the control group (p=0.001). However, in the case group LPST was positive only at 10(-6) and 10(-4) concentrations although statistically not significant (p=0.147). There was no significant relationship between clinically GC resistance and LPST positivity (p=0.405).

CONCLUSION

We determined that in vitro responses to the GCs were significantly declined in the uncontrolled asthma cases. An SRT alone does not seem to be very sensitive for evaluating GC sensitivity, LPST may be performed for demonstrating GC responsiveness in asthmatic patients in addition to SRT.

Non-atopic males with adult onset asthma are at risk of persistent airflow limitation

BACKGROUND

Patients with asthma have on average a more rapid decline in FEV (1) as compared with the general population. Recent cluster analysis has revealed different asthma phenotypes that can be distinguished by age of onset and reversibility of airflow limitation.

OBJECTIVE

This study aimed at detecting risk factors associated with persistent airflow limitation in patients with the adult onset asthma phenotype.

METHODS

We recruited 88 patients with adult onset (≥ 18 years) asthma from an academic pulmonary outpatient clinic in the Netherlands. The associations of age, age of asthma onset, asthma duration, gender, race, atopy, smoking pack-years, BMI, use of oral corticosteroids with post-bronchodilator FEV (1) /FVC were investigated.

RESULTS

Multiple linear regression analysis showed an association of absence of atopy (r = -0.27, B = -0.26, P = 0.01) and male gender (r = 0.31, B = 0.30, P = 0.004) with post-bronchodilator FEV (1) /FVC. Multiple logistic regression analysis showed that male patients were 10.8 (CI: 2.6-45.2) times the odds than women to have an FEV (1) /FVC < 0.7, and non-atopic patients were 5.2 (CI: 1.3-20.3) times the odds to have an FEV (1) /FVC < 0.7 than atopic patients.

CONCLUSIONS AND CLINICAL RELEVANCE

We conclude that in patients with adult onset asthma, male gender and absence of atopy are associated with persistent airflow limitation. This might suggest that amongst patients with adult onset asthma, non-atopic male patients are at increased risk of accelerated decline in lung function.

Role of infection in the development and exacerbation of asthma

Respiratory infections are associated with wheezing illnesses in all ages and may also impact the development and severity of asthma. Respiratory tract infections caused by viruses, Chlamydophila or Mycoplasma have been hypothesized to have significant roles in the pathogenesis of asthma. Progress is being made toward establishing the mechanisms by which these agents can cause acute wheezing and impact the pathophysiology of asthma. Host factors probably contribute to the risk of asthma inception and exacerbation, and these contributions may also vary with respect to early- versus adult-onset disease. This review discusses these various associations as they pertain to the development and exacerbation of asthma.

Pitfalls in the evaluation of shortness of breath

This article illustrates the challenges practitioners face evaluating shortness of breath, a common emergency department complaint. Through a series of patient encounters, pitfalls in the evaluation of shortness of breath are reviewed and discussed.

Asthma phenotypes

PURPOSE OF REVIEW

Asthma is a heterogeneous disorder presenting with many phenotypes. Precise phenotypic definition has eluded the medical research community for years, despite recognition of different disease subtypes. Improved phenotypic characterization and knowledge of underlying pathobiology is necessary for linkage of specific genotypes with clinical disease manifestations.

RECENT FINDINGS

Phenotyping has been difficult because asthma is likely to be comprised of overlapping syndromes with varying origins and heterogeneous pathobiology. Currently, the field is too reliant on classification by trigger or symptoms. Since genotypic and phenotypic heterogeneity are inherent in asthma, patients presenting with different asthma phenotypes may need tailored therapies. Studies have begun to link genetics with disease mechanism and therapeutic response. As disease etiology, onset, progression and severity vary greatly among patients, however, the relative contribution of genetic factors may be difficult to ascertain. Definition of the full array of complex biological consequences of molecular target modulation is a prerequisite for therapies based on this concept.

SUMMARY

The advent of targeted therapies for asthma and clinical trials based on phenotype and genotype have raised interest in more accurate description of asthma phenotypes. Therapies based on phenotypic and genotypic characteristics may be useful in asthma management. A variety of factors, however, must be addressed before such approaches become standard.

The mechanisms, diagnosis, and management of severe asthma in adults

There has been a recent increase in the prevalence of asthma worldwide; however, the 5-10% of patients with severe disease account for a substantial proportion of the health costs. Although most asthma cases can be satisfactorily managed with a combination of anti-inflammatory drugs and bronchodilators, patients who remain symptomatic despite maximum combination treatment represent a heterogeneous group consisting of those who are under-treated or non-adherent with their prescribed medication. After excluding under-treatment and poor compliance, corticosteroid refractory asthma can be identified as a subphenotype characterised by a heightened neutrophilic airway inflammatory response in the presence or absence of eosinophils, with evidence of increased tissue injury and remodelling. Although a wide range of environmental factors such as allergens, smoking, air pollution, infection, hormones, and specific drugs can contribute to this phenotype, other features associated with changes in the airway inflammatory response should be taken into account. Aberrant communication between an injured airway epithelium and underlying mesenchyme contributes to disease chronicity and refractoriness to corticosteroids. The importance of identifying underlying causative factors and the recent introduction of novel therapeutic approaches, including the targeting of immunoglobulin E and tumour necrosis factor alpha with biological agents, emphasise the need for careful phenotyping of patients with severe disease to target improved management of the individual patient's needs.