Underdiagnosis and overdiagnosis of asthma in the morbidly obese

Respir Med. 2013 Sep;107(9):1356-64. doi: 10.1016/j.rmed.2013.05.007. Epub 2013 Jun 10.


Background: The prevalence of obesity and asthma has increased concurrently over the last decades, suggesting a link between obesity and asthma. However, asthma might not be adequately diagnosed in this population.

Aim: To investigate whether not only overdiagnosis but also underdiagnosis of asthma is present in an obese population.

Methods: Morbidly obese subjects with or without physician-diagnosed asthma were recruited from a pre-operative screening programme for bariatric surgery, and were characterized using an extensive diagnostic algorithm.

Results: 473 subjects were screened; 220 met inclusion criteria, and 86 agreed to participate. Among the 32 participating subjects who had a physician diagnosis of asthma, reversible airway obstruction and/or bronchial hyperresponsiveness could only be detected in 19 patients (59%, 95% CI [0.41-0.76]), whereas in 13 patients (41%, 95% CI [0.24-0.50]) the diagnosis of asthma could not be confirmed (overdiagnosis). In contrast, in the remaining 54 patients, 17 (31%, 95% CI [0.20-0.46]) were newly diagnosed with asthma (underdiagnosis).

Conclusion: Besides overdiagnosis, there is also substantial underdiagnosis of asthma in the morbidly obese. Symptoms could be incorrectly ascribed to either obesity or asthma, and therefore also in the morbidly obese the diagnosis of asthma should also be based on pulmonary function testing.

Keywords: ACQ; AQLQ; Asthma; Asthma Control Questionnaire; BHR; BMI; DLCO; ERV; ESS; Epworth Sleepiness Scale; FEF(25–75); FEV(1); FRC; FVC; FeNO; Forced expiratory flow at 25% point to the 75% point of Forced Vital Capacity; GERD; Gastro oesophageal reflux disease; ICS; IOS; Misdiagnosis; Nitric Oxide; OSAS; Obesity; RV; SPT; TLC; body mass index; bronchial hyperresponsiveness; diffusion capacity; expiratory reserve volume; forced expiratory volume in 1 s; forced vital capacity; functional residual capacity; impulse oscillometry; inhaled corticosteroid; mini Asthma Quality of Life Questionnaire; obstructive sleep apnea syndrome; residual volume; skin prick test; total lung capacity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Algorithms
  • Asthma / complications
  • Asthma / diagnosis*
  • Asthma / physiopathology
  • Diagnostic Errors*
  • Female
  • Humans
  • Hypersensitivity / diagnosis
  • Longitudinal Studies
  • Male
  • Middle Aged
  • Obesity, Morbid / complications*
  • Obesity, Morbid / physiopathology
  • Respiratory Function Tests
  • Surveys and Questionnaires
  • Young Adult