Early treatment of asthma

A systematic review of predictive models for asthma development in children

BACKGROUND

Asthma is the most common pediatric chronic disease affecting 9.6 % of American children. Delay in asthma diagnosis is prevalent, resulting in suboptimal asthma management. To help avoid delay in asthma diagnosis and advance asthma prevention research, researchers have proposed various models to predict asthma development in children. This paper reviews these models.

METHODS

A systematic review was conducted through searching in PubMed, EMBASE, CINAHL, Scopus, the Cochrane Library, the ACM Digital Library, IEEE Xplore, and OpenGrey up to June 3, 2015. The literature on predictive models for asthma development in children was retrieved, with search results limited to human subjects and children (birth to 18 years). Two independent reviewers screened the literature, performed data extraction, and assessed article quality.

RESULTS

The literature search returned 13,101 references in total. After manual review, 32 of these references were determined to be relevant and are discussed in the paper. We identify several limitations of existing predictive models for asthma development in children, and provide preliminary thoughts on how to address these limitations.

CONCLUSIONS

Existing predictive models for asthma development in children have inadequate accuracy. Efforts to improve these models' performance are needed, but are limited by a lack of a gold standard for asthma development in children.

Prolonged exposure to damp and moldy workplaces and new-onset asthma

PURPOSE

Epidemiological evidence shows that indoor dampness is associated with respiratory symptoms, the aggravation of preexisting asthma, and the development of new-onset asthma. Follow-up studies indicate that symptoms compatible with asthma constitute risk factors for the future development of asthma. The aims of the study were (1) to assess whether asthma-like symptoms (cough, dyspnea, and wheeze) that occur in relation to exposure to damp and moldy work environments lead to the later development of asthma and (2) to assess the importance of continued exposure to indoor dampness and molds at work in the development of asthma.

METHODS

We followed 483 patients with asthma-like symptoms related to damp workplaces but without objective evidence of asthma in baseline examinations. The development of asthma and present work conditions were established with the use of a questionnaire 3-12 years later.

RESULTS

A total of 62 patients (13%) reported having developed asthma during the study period. Continued exposure to a damp or moldy environment was associated with a more than fourfold increase in the risk of asthma (odds ratio 4.6, 95% confidence interval 1.8-11.6). Working in a non-remediated environment at follow-up was the strongest risk factor for developing asthma. The remediation of damp buildings seemed to be associated with a decrease in the risk of asthma.

CONCLUSIONS

The results indicate that exposure at work to dampness and molds is associated with the occurrence of new-onset asthma. Exposed workers suffering from asthma-like symptoms represent a risk group for the development of asthma. The risk appears especially high if the exposure continues. Due to inherent weaknesses of patient series, the findings need corroborative studies.

Spirometry use among pediatric primary care physicians

OBJECTIVE

This study explores the use of spirometry in primary care settings.

METHODS

A 4-page survey was mailed to a national, random sample of office-based family physicians and pediatricians. Survey items addressed knowledge, attitudes, and practices regarding spirometry and standardized clinical vignettes. Data were analyzed by using χ2 tests and multivariate logistic regression.

RESULTS

Among the 360 respondents who provided care to children with asthma, 52% used spirometry in clinical practice, whereas 80% used peak flow meters and 10% used no lung function tests. Only 21% routinely used spirometry for all guideline-recommended clinical situations. More family physicians than pediatricians reported using spirometry (75% vs 35%; P<.0001), and family physicians were more comfortable in interpreting spirometric results (50% vs 25%; P<.0001). Only one-half of respondents interpreted correctly the spirometric results in a standardized clinical vignette, and the frequency of underrating asthma severity increased with the inclusion of spirometric results. The most common barriers to the use of spirometry, that is, time and training, were cited more often by physicians who did not use spirometry. Two-thirds of respondents agreed that they would want additional training regarding implementing spirometry in their clinical practices.

CONCLUSIONS

The use of spirometry in primary care settings for children with asthma does not conform to national guidelines. Widespread implementation of national asthma guidelines likely would require a major educational initiative to address deficiencies in spirometry interpretation and other barriers.

Timeliness of diagnosis of asthma in children and its predictors

BACKGROUND

There is a paucity of literature using medical records to evaluate the timeliness of asthma diagnosis in children and the predictors associated with timeliness of asthma diagnosis.

METHODS

Subjects were obtained from a convenience sample of 839 children, aged 5-13 years. We conducted comprehensive medical record reviews for these children to determine their asthma status by applying predetermined criteria for asthma. Predictors were evaluated for an association with timeliness of asthma diagnosis.

RESULTS

Of 839 children, 276 children met the criteria for asthma before 18 years of age. Of these subjects, 97 had timely diagnosis of asthma while 179 did not have timely diagnosis of asthma with the median delay of 3.3 years. Children with definite asthma at the time of index date was three times more timely to be diagnosed with asthma [hazard ratios (HR) 3.3, 95% CI: 2.43-4.47, P < 0.001], compared to those with probable asthma. Children with a family history of asthma were more timely to be diagnosed with asthma (HR 1.36, 95% CI: 1.03-1.8, P = 0.031). Children with exercise-induced wheezing or bronchospasm were more timely to be diagnosed with asthma (HR 1.79, 95% CI: 0.95-3.36, P = 0.07), compared to those with spasmodic (or bronchospastic) cough.

CONCLUSIONS

Many asthmatic children are not diagnosed with asthma in a timely manner, especially in those without the commonly recognized factors associated with asthma. Health care providers need to be reminded that asthma can still occur in those without commonly recognized risk factors. Asthma guidelines need to emphasize this aspect.

Use of Phadiatop Infant in diagnosis of specific sensitization in young children with wheeze or eczema

Wheezing and eczema are common symptoms in young children and it is important to disclose sensitization for correct management. The objective of this study was to assess the diagnostic values of Phadiatop Infant, an in vitro test for graded determination of immunoglobulin E (IgE) antibodies to food and inhalant allergens. One-hundred and forty-nine children (median age 1.4 yr) with symptoms of wheezing (51%) eczema (28%) or a combination of both (21%) were classified as atopic or non-atopic based on case history, atopic history, physical examination and determination of IgE antibodies. The clinical performance of Phadiatop Infant was evaluated for 145 children against this classification in a blinded manner to the allergist. Fifty-one children were classified as atopic of which Phadiatop Infant identified 49. Ninety-four were non-atopic of which the test identified 90. This resulted in a sensitivity of 96%, a specificity of 96%, a positive and a negative predictive value of 94% and 98%, respectively. Logistic regression showed that probability had to be assessed as atopic increased with increasing Phadiatop Infant values. These results suggest that Phadiatop Infant can be recommended as an adjunct to the clinical information in the differential diagnosis on IgE-mediated allergy in young children. The test thus provides an opportunity for early correct diagnosis and identification of subjects at risk for whom intervention may be necessary.

[Assessing the risk of asthma in infants and pre-school children]

Childhood asthma is a heterogeneous inflammatory disease with several wheezing phenotypes (transient, atopic, nonatopic, and obese) and various clinical expressions of multifactorial origin. All forms, however, follow a similar course characterized by recurrent episodes of airway obstruction. Studies have shown that the onset of disease occurs early in life for the great majority of asthmatics, that airway inflammation and remodeling are present in schoolchildren with asthma, and that even infants with persistent wheezing present airway inflammation. The difficulty lies in the early identification of infants with recurrent wheezing who are at risk of suffering persistent asthma later in life. The Asthma Predictive Index, a simple tool validated in a longitudinal study, has been suggested for early identification of infants with recurrent wheezing who are at risk of developing asthma and whose lung function has undergone major irreversible damage during the first years of life.

Asthma therapy for children under 5 years of age

PURPOSE OF REVIEW

The evidence for effectiveness of currently used asthma medication for wheeze in young children is reviewed.

RECENT FINDINGS

The management of the infant and preschool child with wheezing is complicated by the uncertainty with respect to the aetiology. Difficulties in defining phenotypes and objective outcome parameters combined with the transient nature of symptoms which often resolve spontaneously have confounded many therapeutic studies. Recent studies on the effect of pharmacotherapy in wheezing infants have tried to define a more homogeneous phenotype as well as make a selection of patients that are likely to respond to the studied drug. In addition, these studies have used lung function parameters and nitric oxide as one of the outcome measurements. Studies on the nature of inflammation and the development of airway remodelling in infants and young children are done to further define phenotypes.

SUMMARY

Currently, there are no evidence-based guidelines and not even consensus statements on the right approach in pharmacological treatment of wheezing in infants and preschool children. The main issue still is the difficulty in coming to a correct diagnosis. Further studies are needed on the nature and the diagnostics of phenotypes and on the effect of early intervention.

Childhood asthma: breakthroughs and challenges

As we move forward, our goal is to control and eliminate asthma and other allergic disorders. This may come through broadly applied manipulation of environmental, dietary, and infectious risk factors, possibly during the perinatal period. Or we may learn to identify genetically susceptible children and to intervene with individualized genotype-specific treatment before the onset of disease. Maybe we'll learn how to block the mechanisms that give rise to chronic inflammation, or how to subdue Th2 activation. However, as the Swedish proverb says--Don't throw away the old bucket until you know whether the new one holds water. To continue using the old bucket, we have to fix the leaks. One approach to reducing asthma disparities is through traditional disease prevention stages. Primary prevention targets asthma incidence; secondary prevention mitigates established disease and involves disease detection, management, and control; and tertiary prevention is the reduction of complications caused by severe disease. Once causative factors at each level of disease prevention are understood, this knowledge can be translated into clinical practice and public health policy. We need reliable diagnostic criteria to provide correct treatment for infants and toddlers. This will require longitudinal cohort studies supported by assessment of pulmonary function and inflammatory markers. We must find ways to convince more physicians to embrace controller therapy for more severe disease, and to identify the patients with less severe disease who also require ongoing controller therapy. We need to close the gap between what we know and what we do in practice. We need to link basic research to healthcare delivery, and to gain acceptance and support from the intended recipients of new interventions. We need better strategies for improving adherence. We need accountability, foresight, and imagination.

Prevalence and clinical features of cough variant asthma in a general internal medicine outpatient clinic in Japan

OBJECTIVE

The aims of the present study were to examine the prevalence and clinical features of cough variant asthma (CVA) among patients with chronic and persistent cough at an outpatient clinic in Japan, and the efficacy of treatment with an inhaled corticosteroid.

METHODOLOGY

This prospective study was conducted at a general internal medicine outpatient clinic in Japan over a 12-month period. CVA was diagnosed as chronic cough without wheezing or any apparent cause, that had persisted for more than 8 weeks, with a normal CXR and spirometry but with bronchial hyperresponsiveness to methacholine, and relief of cough after bronchodilator treatment. We also examined the effects of inhaled beclomethasone propionate on symptoms and differences in PEF between early morning and evening.

RESULTS

Of 55 patients suffering from chronic cough, 23 satisfied the criteria for CVA. Their cough occurred more frequently at night and early in the morning. Early morning PEF was significantly lower than evening PEF with a mean variability of 11.5 +/- 4.1%. Treatment with beclomethasone propionate improved coughing and significantly increased early morning PEF, reducing variability to less than 10%.

CONCLUSIONS

These findings suggest that CVA is most common among patients with chronic cough not due to any apparent cause. The efficacy of inhaled corticosteroid suggests that early intervention is effective in the treatment of CVA.

Is mild asthma really 'mild'?

Current evidence suggests that patients with mild asthma are often under-recognised, and those that are diagnosed can remain with this initial classification and be treated accordingly, despite worsening of their condition. There is considerable overlap between mild and more severe asthma in terms of the underlying pathophysiology and poorly reversible airway changes, such as subepithelial fibrosis and airway wall remodelling, which are present very early in the progression of asthma in patients with normal lung function. Life-threatening exacerbations can also occur in patients with mild asthma. In view of these factors and given that asthma is a two-component disease (airway inflammation and smooth muscle dysfunction), recent studies have examined the effects of both early intervention with steroids and combination therapy comprising an inhaled steroid and a long acting beta(2)-agonist. These studies suggest that early intervention is likely to provide better asthma control and possibly prevent or delay the worsening of disease and fatalities in patients considered to be mild asthmatics.

Effects on sick leave of an inpatient rehabilitation programme for asthmatics in a randomized trial

AIM

Among adult asthmatics a major proportion of the cost of illness is attributed to productivity losses and societal costs in connection with sick leave compensation. The aim of the study was to evaluate an extensive structured four-week inpatient rehabilitation programme for asthmatics.

METHODS

A diagnosis of asthma was made in a structured way among people on sick leave due to a respiratory disorder. In total, 197 persons were randomized to either a rehabilitation programme, or to usual care. The main components of the rehabilitation programme were education, pharmacological optimization, physical training, and coping skill acquisition.

RESULTS

At the three-year follow-up, the median number of sick leave days in the rehabilitation group was 104, and in the usual care group 167 (p = 0.12). An analysis of a subgroup consisting of persons not currently smoking with a previous diagnosis of asthma by a physician (n = 57) showed a significant effect on sick leave at three years (median number of days 63 in the rehabilitation group vs 361 in the control group, p = 0.02). All analyses were based on intention to treat.

CONCLUSIONS

The long-term effects on sick leave of an extensive inpatient asthma rehabilitation programme are most evident for non-smokers and ex-smokers with a previous asthma diagnosis. It is therefore recommended that persons with asthma who are current smokers should be offered participation in smoking cessation programmes instead of asthma rehabilitation programmes.

The impact of budesonide and other inhaled corticosteroid therapies in the management of asthma in children and adults

BACKGROUND

Since the recognition that asthma is characterized by extensive inflammation of the airways, the use of inhaled corticosteroids (ICSs) as controller therapy has become central to successful disease management. As the prevalence of asthma increases worldwide, there is concern about increasing numbers of patients with untreated or undertreated asthma, which may lead to deterioration in disease control, with direct effects on morbidity and mortality rates. The costs attributed to asthma translate into a considerable economic burden, from the direct costs of medical treatment to the costs incurred through lost work or school days. International treatment guidelines currently recommend early intervention with ICS therapy to improve lung function and disease control.

OBJECTIVE

This article reviews the role of therapy with ICSs, particularly budesonide, in improving the management of asthma in patients of all ages and in reducing the economic and social burdens of this disease.

RESULTS

Randomized, controlled clinical studies confirm the efficacy of early intervention with ICSs in patients with mild persistent asthma. Regular use of an ICS can reduce the number of exacerbations and hospitalizations in patients of all ages and with all disease severities.

CONCLUSIONS

Budesonide has a well-established efficacy and safety profile. Its once-daily dosing may contribute to improved adherence and cost-effectiveness.

Interrupter resistance and wheezing phenotypes at 4 years of age

It is difficult to distinguish young children with respiratory symptoms who will develop asthma from those with transient symptoms only. Measurement of interrupter resistance may help to identify children at high risk of asthma. The aim of this study is to compare interrupter resistance in 4-year-old children with different wheezing phenotypes. All children participated in the Prevention and Incidence of Asthma and Mite Allergy cohort, a prospective birth cohort of more than 4,000 children. At 4 years of age, data on interrupter resistance plus wheezing phenotype were available for 838 children. Mean interrupter resistance values (95% confidence interval) were 0.95 (0.93, 0.97), 0.95 (0.92, 0.98), 0.96 (0.87, 1.05), and 1.08 (1.02, 1.14) kPa.L(-1).second for never (n = 482), early transient (n = 236), late-onset (n = 22), and persistent (n = 98) wheezing phenotypes, respectively. Additional analyses were performed for children with atopic and nonatopic mothers separately. Both in children with atopic and nonatopic mothers, children with persistent wheeze had significantly higher interrupter resistance values than children with never and early wheeze. In conclusion, mean interrupter resistance values were higher in children with persistent wheeze as compared with children with never and early transient wheezing phenotypes.

Differential inhibition of thrombin- and EGF-stimulated human cultured airway smooth muscle proliferation by glucocorticoids

The present study compared the effects of glucocorticoids on thrombin- and EGF-stimulated proliferation in human cultured airway smooth muscle (ASM) to identify pathways that may be differentially regulated by glucocorticoids. Mitogenic responses to thrombin were inhibited by extracellular-regulated kinase (ERK 1/2) and phosphoinositide 3-kinase (PI3K) inhibitors, whereas mitogenic responses to EGF were inhibited by ERK 1/2 and PI3K inhibitors as well as by the p38 mitogen activated protein kinase inhibitor, SB203580 (10 microM). Mitogenic responses to thrombin were more sensitive to inhibition by dexamethasone (Dex) or fluticasone propionate (FP) than were those to EGF. Elevated cyclin D1 protein and mRNA levels induced by thrombin and EGF were attenuated equally by glucocorticoids. The protein or mRNA levels of the cyclin-dependent kinase inhibitors (cdki) p21(Cip1), p27(Kip1) were unaffected by Dex treatment of ASM cells treated with mitogens. The resistance of EGF-induced proliferation to inhibition by glucocorticoids is not associated with a failure to regulate cyclin D1 induction, nor does it appear to be explained by differential regulation of the levels of the cdki's, p21(Cip1) and p27(Kip1).

Diagnosing pediatric asthma: validating the Easy Breathing Survey

OBJECTIVE

To determine the sensitivity, specificity, and predictive value of a simple, self-administered questionnaire for the diagnosis of asthma in children.

STUDY DESIGN

A questionnaire specifically designed to assist primary care providers in making a diagnosis of asthma in children was developed and administered in 4 different primary care and subspecialty clinics, validated, and then used as part of an asthma management program called Easy Breathing. Asthma diagnoses were made according to recommended National Asthma Expert Panel Guidelines.

RESULTS

Four questions on the survey were shown to be sensitive and specific for asthma. The sensitivity was greater for all levels (mild, moderate, and severe) of persistent asthma than for mild, intermittent asthma. A positive response to any 1 of the 4 questions was over 94% sensitive for asthma; a negative response to all 4 questions was 55% specific for ruling out asthma.

CONCLUSIONS

Patient responses to 4 specific respiratory symptom questions can assist primary care providers in diagnosing asthma in children. Primary care providers serving pediatric populations at high risk for asthma should consider asking patients or their parents these 4 questions regarding asthma symptoms on a regular basis.