title: Systemic inflammation and higher perception of dyspnea mimicking asthma in obese subjects.
abstract: BACKGROUND
  There are a variable number of obese subjects with self-reported diagnosis of asthma but without current or previous evidence of airflow limitation, bronchial reversibility, or airway hyperresponsiveness (misdiagnosed asthma). However, the mechanisms of asthma-like symptoms in obesity remain unclear.
  
  
  OBJECTIVE
  We sought to evaluate the perception of dyspnea during bronchial challenge and exercise testing in obese patients with asthma and misdiagnosed asthma compared with obese control subjects to identify the mechanisms of asthma-like symptoms in obesity.
  
  
  METHODS
  In a cross-sectional study we included obese subjects with asthma (n = 25), misdiagnosed asthma (n = 23), and no asthma or respiratory symptoms (n = 27). Spirometry, lung volumes, exhaled nitric oxide levels, and systemic biomarker levels were measured. Dyspnea scores during adenosine bronchial challenge and incremental exercise testing were obtained.
  
  
  RESULTS
  During bronchial challenge, patients with asthma or misdiagnosed asthma reached a higher Borg-FEV1 slope than control subjects. Moreover, maximum dyspnea and the Borg-oxygen uptake (V'O2) slope were significantly greater during exercise in subjects with asthma or misdiagnosed asthma than in control subjects. The maximum dyspnea achieved during bronchial challenge correlated with IL-1β levels, whereas peak respiratory frequency, ventilatory equivalent for CO2, and IL-6 and IL-1β levels were independent predictors of the Borg-V'O2 slope during exercise (r(2) = 0.853, P < .001).
  
  
  CONCLUSIONS
  A false diagnosis of asthma (misdiagnosed asthma) in obese subjects is attributable to an increased perception of dyspnea, which, during exercise, is mainly associated with systemic inflammation and excessive ventilation for metabolic demands.
authors.affiliation: Servicio de Neumología, Hospital Universitario La Paz, IdiPAZ, Madrid, Spain; CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Carpio
authors.affiliation: Servicio de Neumología, Hospital Universitario La Paz, IdiPAZ, Madrid, Spain; CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Villasante
authors.affiliation: Servicio de Neumología, Hospital Universitario La Paz, IdiPAZ, Madrid, Spain; CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain.
authors.forename: Raúl
authors.initials: R
authors.lastname: Galera
authors.affiliation: Servicio de Neumología, Hospital Universitario La Paz, IdiPAZ, Madrid, Spain; CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Romero
authors.affiliation: Unidad de Obesidad, Servicio de Endocrinología y Nutrición, IdiPAZ, Madrid, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: de Cos
authors.affiliation: Servicio de Bioquímica, Hospital Universitario La Paz, IdiPAZ, Madrid, Spain.
authors.forename: Angel
authors.initials: A
authors.lastname: Hernanz
authors.affiliation: Servicio de Neumología, Hospital Universitario La Paz, IdiPAZ, Madrid, Spain; CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain; Universidad Autónoma de Madrid, Madrid, Spain. Electronic address: fgr01m@gmail.com.
authors.forename: Francisco
authors.initials: F
authors.lastname: García-Río
mesh_terms: D052242:Adiponectin / Q000097:blood; D000328:Adult; D001249:Asthma / Q000150:complications* / Q000175:diagnosis* / Q000378:metabolism / Q000503:physiopathology; D015415:Biomarkers; D001985:Bronchial Provocation Tests; D003430:Cross-Sectional Studies; D003937:Diagnosis, Differential; D004417:Dyspnea / Q000175:diagnosis* / Q000209:etiology* / Q000378:metabolism / Q000503:physiopathology; D045853:Exhalation; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D007249:Inflammation / Q000150:complications*; D053583:Interleukin-1beta / Q000097:blood; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide; D009765:Obesity / Q000150:complications*; D012129:Respiratory Function Tests; D012307:Risk Factors; D013147:Spirometry
chemical_list: D052242:Adiponectin; D015415:Biomarkers; D053583:Interleukin-1beta; D009569:Nitric Oxide
keywords: Obesity; asthma; dyspnea; inflammation