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The burden of exacerbations in mild asthma: a systematic review.

ABSTRACT: Background:Although most patients with asthma have mild disease, data on how mild asthma is defined, and how frequently exacerbations occur in this patient population are scarce, so we aimed to redress this. Methods:We searched Medline and Medline In-Process (PubMed), and Embase in OVID for English-language publications containing "mild asthma" plus at least one relevant therapy and outcome/keyword, limited to randomised controlled trials (RCTs) and observational studies published between January 1990 and February 2019. Publications were filtered to ensure appropriate data extraction. The main outcomes were the definitions of mild asthma and exacerbations, baseline exacerbation rates and exacerbation data for placebo recipients in prospective studies. Meta-analysis of exacerbation rates was planned. Findings:Of 4064 articles identified, 64 were included in our review (49?743 subjects); 54 RCTs and 10 observational/other studies. Six main types of definitions of mild asthma were identified. While care was taken to ensure inclusion only of patients with mild asthma, marked heterogeneity was revealed in the definitions of mild asthma and hence the study populations. Reporting of exacerbations also varied widely between studies, precluding meta-analysis. Between 0-22% of patients were hospitalised for asthma or had a severe exacerbation in the previous year, according to baseline data from prospective studies. In RCTs, severe exacerbation rates in placebo recipients taking only short-acting ?2-agonist therapy ranged from 0.20-2.88 per year. Conclusions:These data provide new evidence of the burden of exacerbations in mild asthma and highlight the need for standardised definitions of mild asthma and of exacerbations to progress further research.

SUBMITTER: FitzGerald JM

PROVIDER: S-EPMC7418821 | biostudies-literature | 2020 Jul

REPOSITORIES: biostudies-literature

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The burden of exacerbations in mild asthma: a systematic review.

FitzGerald J Mark JM Barnes Peter J PJ Chipps Bradley E BE Jenkins Christine R CR O'Byrne Paul M PM Pavord Ian D ID Reddel Helen K HK

ERJ open research 20200701 3

<h4>Background</h4>Although most patients with asthma have mild disease, data on how mild asthma is defined, and how frequently exacerbations occur in this patient population are scarce, so we aimed to redress this.<h4>Methods</h4>We searched Medline and Medline In-Process (PubMed), and Embase in OVID for English-language publications containing "mild asthma" plus at least one relevant therapy and outcome/keyword, limited to randomised controlled trials (RCTs) and observational studies published ...[more]

PMID: 32802826

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Project description:Asthma and chronic obstructive pulmonary disease (COPD) cause significant morbidity and mortality worldwide, primarily through exacerbations. Exacerbations are often treated with antibiotics but their optimal course duration is uncertain. Reducing antibiotic duration may influence antimicrobial resistance but risks treatment failure. The objective of this article is to review published literature to investigate whether shorter antibiotic therapy duration affects clinical outcomes in the treatment of asthma and COPD exacerbations. We systematically searched electronic databases (MEDLINE, EMBASE, CINAHL, World Health Organisation International Clinical Trial Registry Platform, the Cochrane library, and ISRCTN) with no language, location, or time restrictions. We retrieved observational and controlled trials comparing different durations of the same oral antibiotic therapy in the treatment of acute exacerbations of asthma or COPD in adults. We found no applicable studies for asthma exacerbations. We included 10 randomized, placebo-controlled trials for COPD patients, all from high-income countries. The commonest studied antibiotic class was fluoroquinolones. Antibiotic courses shorter than 6 days were associated with significantly fewer overall adverse events (risk ratio (RR): 0.84, 95% confidence interval (CI): 0.75-0.93, p = 0.001) when compared with those of 7 or more days. There was no statistically significant difference for clinical success or bacteriological eradication in sputum (RR: 1.00, 95% CI: 0.88-1.13 and RR: 1.06, 95% CI: 0.79-1.44, respectively). Shorter durations of antibiotics for COPD exacerbations do not seem to confer a higher risk of treatment failure but are associated with fewer adverse events. This is in keeping with previous studies in community acquired pneumonia, but studies were heterogeneous and differed from usual clinical practice. Further observational and prospective work is needed to explore the significance of antibiotic duration in the treatment of asthma and COPD exacerbations.

Project description:BackgroundAsthma exacerbations reduce the patient's quality of life and are also responsible for significant disease burdens and economic costs. Machine learning (ML)-based prediction models have been increasingly developed to predict asthma exacerbations in recent years. This systematic review and meta-analysis aimed to identify the prediction performance of ML-based prediction models for asthma exacerbations and address the uncertainty of whether modern ML methods could become an alternative option to predict asthma exacerbations.MethodsPubMed, Cochrane Library, EMBASE, and Web of Science were searched for studies published up to December 15, 2022. Studies that applied ML methods to develop prediction models for asthma exacerbations among asthmatic patients older than five years and were published in English were eligible. The prediction model risk of bias assessment tool (PROBAST) was utilized to estimate the risk of bias and the applicability of included studies. Stata software (version 15.0) was used for the random effects meta-analysis of performance measures. Subgroup analyses stratified by ML methods, sample size, age groups, and outcome definitions were conducted.ResultsEleven studies, including 23 prediction models, were identified. Most of the studies were published in recent three years. Logistic regression, boosting, and random forest were the most used ML methods. The most common important predictors were systemic steroid use, short-acting beta2-agonists, emergency department visit, age, and exacerbation history. The overall pooled area under the curve of the receiver operating characteristics (AUROC) of 11 studies (23 prediction models) was 0.80 (95% CI 0.77-0.83). Subgroup analysis based on different ML models showed that boosting method achieved the best performance, with an overall pooled AUROC of 0.84 (95% CI 0.81-0.87).ConclusionThis study identified that ML was the potential tool to achieve great performance in predicting asthma exacerbations. However, the methodology within these models was heterogeneous. Future studies should focus on improving the generalization ability and practicability, thus driving the application of these models in clinical practice.

Project description:BackgroundRhinovirus (RV) infections are a major cause of asthma exacerbations. Unlike other respiratory viruses, RV causes minimal cytotoxic effects on airway epithelial cells and cytokines play a critical role in its pathogenesis. However, previous findings on RV-induced cytokine responses were largely inconsistent. Thus, this study sought to identify the cytokine/chemokine profiles induced by RV infection and their correlations with airway inflammatory responses and/or respiratory symptoms using systematic review, and to determine whether a quantitative difference exists in cytokine levels between asthmatic and healthy individuals via meta-analysis.MethodsRelevant articles were obtained from PubMed, Scopus, and ScienceDirect databases. Studies that compared RV-induced cytokine responses between asthmatic and healthy individuals were included in the systematic review, and their findings were categorized based on the study designs, which were ex vivo primary bronchial epithelial cells (PBECs), ex vivo peripheral blood mononuclear cells (PBMCs), and human experimental studies. Data on cytokine levels were also extracted and analyzed using Review Manager 5.4.ResultsThirty-four articles were included in the systematic review, with 18 of these further subjected to meta-analysis. Several studies reported the correlations between the levels of cytokines, such as IL-8, IL-4, IL-5, and IL-13, and respiratory symptoms. Evidence suggests that IL-25 and IL-33 may be the cytokines that promote type 2 inflammation in asthmatics after RV infection. Besides that, a meta-analysis revealed that PBECs from children with atopic asthma produced significantly lower levels of IFN-β [Effect size (ES): -0.84, p = 0.030] and IFN-λ (ES: -1.00, p = 0.002), and PBECs from adult atopic asthmatics produced significantly lower levels of IFN-β (ES: -0.68, p = 0.009), compared to healthy subjects after RV infection. A trend towards a deficient production of IFN-γ (ES: -0.56, p = 0.060) in PBMCs from adult atopic asthmatics was observed. In lower airways, asthmatics also had significantly lower baseline IL-15 (ES: -0.69, p = 0.020) levels.ConclusionOverall, RV-induced asthma exacerbations are potentially caused by an imbalance between Th1 and Th2 cytokines, which may be contributed by defective innate immune responses at cellular levels. Exogenous IFNs delivery may be beneficial as a prophylactic approach for RV-induced asthma exacerbations.Systematic review registrationhttps://www.crd.york.ac.uk/prospero/display_record.php?RecordID=184119, identifier CRD42020184119.

Project description:BackgroundAsthma is one of the neglected diseases in Africa with a high prevalence. Allergic fungal diseases have been reported to complicate asthma progression and treatment outcomes. However, data about fungal asthma and its associated complications are limited in Africa. We aimed to estimate the burden of fungal asthma among adults and children in Africa using a systematic review.MethodsWe first engaged the Institute for Health Metrics and Evaluation (IHME) to highlight the trend in morbidity and mortality attributed to asthma in Africa. We then searched PubMed, HINARI and Google Scholar for all studies of any design focusing on fungal asthma in any African country. Languages were restricted to English and French, but not year of publication. We estimated the weighted prevalence of allergic fungal infections among asthmatics with a 95% CI and pooled the results using a random effects model. This study is registered with PROSPERO, number CRD42019117319.ResultsThe IHME data showed that there has been a gradual increase in morbidity and mortality due to asthma in African adults with a prevalence of 4%. Our search retrieved 5233 citations. We retained 20 studies that met our selection criteria. These were from 13 African countries published between 1967 and 2018. There were eight cross-sectional studies and twelve review articles. The average asthma prevalence in Africa was 6% from these studies. The prevalence of fungal sensitisation was relatively high (3-52%) in the asthmatic population with an average of 28% and a pooled estimate of 23.3%, mostly due to Aspergillus species. Prevalence of Allergic bronchopulmonary apsergillosis was estimated at 1.6-21.2%. Diagnosis of fungal allergy was mostly made by skin prick tests. There was no data on the use of medication to manage fungal asthma. None of the studies evaluated the association between fungal allergy and asthma severity. Data were lacking in children.ConclusionThere is a high prevalence of fungal sensitization among Africans with asthma. Fungal asthma is a significant problem in Africa but there remains a paucity of data on the epidemiology and associated complications. There is urgent need for national epidemiological studies to estimate the actual burden of fungal asthma in Africa.

Project description:BACKGROUND:A previous aggregate data meta-analysis of randomised controlled trials showed that vitamin D supplementation reduces the rate of asthma exacerbations requiring treatment with systemic corticosteroids. Whether this effect is restricted to patients with low baseline vitamin D status is unknown. METHODS:For this systematic review and one-step and two-step meta-analysis of individual participant data, we searched MEDLINE, Embase, the Cochrane Central Register of Controlled Trials, and Web of Science for double-blind, placebo-controlled, randomised controlled trials of vitamin D3 or vitamin D2 supplementation in people with asthma that reported incidence of asthma exacerbation, published between database inception and Oct 26, 2016. We analysed individual participant data requested from the principal investigator for each eligible trial, adjusting for age and sex, and clustering by study. The primary outcome was the incidence of asthma exacerbation requiring treatment with systemic corticosteroids. Mixed-effects regression models were used to obtain the pooled intervention effect with a 95% CI. Subgroup analyses were done to determine whether effects of vitamin D on risk of asthma exacerbation varied according to baseline 25-hydroxyvitamin D (25[OH]D) concentration, age, ethnic or racial origin, body-mass index, vitamin D dosing regimen, use of inhaled corticosteroids, or end-study 25(OH)D levels; post-hoc subgroup analyses were done according to sex and study duration. This study was registered with PROSPERO, number CRD42014013953. FINDINGS:Our search identified 483 unique studies, eight of which were eligible randomised controlled trials (total 1078 participants). We sought individual participant data for each and obtained it for seven studies (955 participants). Vitamin D supplementation reduced the rate of asthma exacerbation requiring treatment with systemic corticosteroids among all participants (adjusted incidence rate ratio [aIRR] 0·74, 95% CI 0·56-0·97; p=0·03; 955 participants in seven studies; high-quality evidence). There were no significant differences between vitamin D and placebo in the proportion of participants with at least one exacerbation or time to first exacerbation. Subgroup analyses of the rate of asthma exacerbations treated with systemic corticosteroids revealed that protective effects were seen in participants with baseline 25(OH)D of less than 25 nmol/L (aIRR 0·33, 0·11-0·98; p=0·046; 92 participants in three studies; moderate-quality evidence) but not in participants with higher baseline 25(OH)D levels (aIRR 0·77, 0·58-1·03; p=0·08; 764 participants in six studies; moderate-quality evidence; pinteraction=0·25). p values for interaction for all other subgroup analyses were also higher than 0·05; therefore, we did not show that the effects of this intervention are stronger in any one subgroup than in another. Six studies were assessed as being at low risk of bias, and one was assessed as being at unclear risk of bias. The two-step meta-analysis did not reveal evidence of heterogeneity of effect (I2=0·0, p=0·56). INTERPRETATION:Vitamin D supplementation reduced the rate of asthma exacerbations requiring treatment with systemic corticosteroids overall. We did not find definitive evidence that effects of this intervention differed across subgroups of patients. FUNDING:Health Technology Assessment Program, National Institute for Health Research (reference number 13/03/25).

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The burden of exacerbations in mild asthma: a systematic review.

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The burden of exacerbations in mild asthma: a systematic review.

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