Identification of Asthma Phenotypes in the Spanish MEGA Cohort Study Using Cluster Analysis.

Introduction: The definition of asthma phenotypes has not been fully established, neither there are cluster studies showing homogeneous results to solidly establish clear phenotypes. The purpose of this study was to develop a classification algorithm based on unsupervised cluster analysis, identifying clusters that represent clinically relevant asthma phenotypes that may share asthma-related outcomes.

Methods: We performed a multicentre prospective cohort study, including adult patients with asthma (N=512) from the MEGA study (Mechanisms underlying the Genesis and evolution of Asthma).

Clinical and inflammatory characteristics of patients with asthma in the Spanish MEGA project cohort.

Introduction: The MEGA (MEchanism underlying the Genesis and evolution of Asthma) project is a multicenter cohort study carried out in eight Spanish hospitals, gathering clinical, physiological, and molecular data from patients with asthma and multimorbidities in order to gain insight into the different physiopathological mechanisms involved in this disorder.

Material And Methods: We report the baseline clinical and physiological characteristics and biomarker measures of adult participants in the project with the aim of better understanding the natural history and underlying mechanisms of asthma as well as the associated multimorbidities across different levels of severity. We carried out a detailed clinical examination, pulmonary function testing, measurement of fractional exhaled nitric oxide (FeNO), blood counts, induced sputum, skin prick tests, chest computed tomography scan, asthma questionnaires, and multimorbidity assessment in 512 asthmatic patients.

The MEGA Project: A Study of the Mechanisms Involved in the Genesis and Disease Course of Asthma. Asthma Cohort Creation and Long-Term Follow-Up.

The general aim of this study is to create a cohort of asthma patients with varying grades of severity in order to gain greater insight into the mechanisms underlying the genesis and course of this disease. The specific objectives focus on various studies, including imaging, lung function, inflammation, and bronchial hyperresponsiveness, to determine the relevant events that characterize the asthma population, the long-term parameters that can determine changes in the severity of patients, and the treatments that influence disease progression. The study will also seek to identify the causes of exacerbations and how this affects the course of the disease.

Optimal duration of allergen immunotherapy in children with dust mite respiratory allergy.

Background: Subcutaneous immunotherapy (SCIT) discontinuation data in children remain scarce.

Objective: We sought for differences in the clinical efficacy of 3 vs. 5 yr of SCIT in children with dust mite respiratory allergy.

[Physiology and physiopathology of the distal airways in asthma].

The small airways are those with an internal diameter of less than 2 mm. The contribution of these airways to total airflow resistance is small in healthy individuals but can represent 50-90 % of total airflow resistance in asthmatics. Suspicion of small airways disease has been based on reduction of midexpiratory and instantaneous flows, although wide variability in their values and the absence of a sufficiently validated cut-off point has limited their clinical application.

Three years of specific immunotherapy may be sufficient in house dust mite respiratory allergy.

Background: Specific immunotherapy (SIT) duration for respiratory allergy is currently based on individual decisions.

Objective: To evaluate the differences in clinical efficacy of SIT as a result of the duration between the current recommended limits (3-5 years).

Methods: A 5-year prospective, controlled clinical trial of SIT blind until the first year and randomization to a 3-year (IT3) or 5-year (IT5) course was conducted.

Is exhaled nitric oxide a useful adjunctive test for assessing asthma?

Rationale: To determine the general utility of clinical (Asthma Control Test) and physiologic (forced expiratory volume in the first second of exhalation [FEV(1)] and fractionated exhaled nitric oxide level [FeNO]) parameters for characterizing asthma patients.

Methods: Two cross-sectional independent studies simultaneously enrolled 100 patients in the US and 109 patients in Spain > or = 18 years of age with a physician-diagnosis of asthma and confirmed by a > or = 12% improvement in FEV(1) after bronchodilators or the presence of airway hyperresponsiveness, a central feature of asthma, as measured by methacholine challenge (PC(20) < 10 mg/mL). There was no restriction on asthma severity or treatment.

Carmine (E-120)-induced occupational asthma revisited.

Background: Occupational asthma (OA) caused by carmine (E-120) has been reported.

Objective: We sought to evaluate the prevalence of sensitization and OA at a natural dye processing factory in which 2 workers had been given a diagnosis of carmine-induced OA 6 years previously.

Methods: The 24 current employees and one worker who had recently left work because of asthma completed a questionnaire and underwent skin testing (carmine, cochineal, carminic acid, curcuma, annato, and chlorophyll), carmine IgE dot-blot analysis, and methacholine inhalation testing.

Sputum eosinophilia and maximal airway narrowing in Dermatophagoides pteronyssinus allergic rhinitis patients: only rhinitis or rhinitis plus mild asthma?

Study Objective: To study the existence of bronchial disease among rhinitis patients. To evaluate the laboratory test or set of tests (ie, symptoms, exposure, and sensitization to the allergen, and the provocative dose of methacholine [Mth] causing a 20% fall in FEV(1) [PD(20)] and the maximal response plateau [MRP] to Mth) that best identifies a case of mild asthma.

Design: Cross-sectional analysis in 52 Dermatophagoides pteronyssinus-monosensitized patients who were consulting a physician for perennial rhinitis.