Investigation of factors associated with difficult-to-control asthma

J Bras Pneumol. 2007 Sep-Oct;33(5):495-501. doi: 10.1590/s1806-37132007000500003.
[Article in English, Portuguese]


Objective: To determine the prevalence of factors associated with difficult-to-control asthma.

Methods: Patients with severe asthma were selected from the outpatient asthma clinic of the Ribeirão Preto School of Medicine Hospital das Clínicas. The patients were divided into two groups: controlled severe asthma and difficult-to-control severe asthma. After new attempts to optimize the severe asthma treatment, a questionnaire was applied, and additional tests for factors associated with difficult-to-control asthma, such as environmental and occupational exposure, smoking history, social factors, rhinitis/sinusitis, gastroesophageal reflux disease (GERD), obstructive sleep apnea, congestive heart failure (CHF), pulmonary embolism, cystic fibrosis, vocal cord dysfunction, alpha-1 antitrypsin deficiency, and Churg-Strauss syndrome, were performed.

Results: 77 patients with severe asthma were selected, of which 47 suffered from hard-to-control asthma, being 68.1% female, with mean age of 44.4 years (+/-14.4), and forced expiratory volume in one second of 54.7% (+/-18.3). The most factors most often associated with difficult-to-control asthma were noncompliance with treatment (68%), rhinitis/sinusitis (57%), GERD (49%), environmental exposure (34%), occupational exposure (17%), smoking history (10%), obstructive sleep apnea (2%), and CHF (2%). At least one of these factors was identified in every case.

Conclusions: Noncompliance with treatment was the factor most often associated with difficult-to-control asthma, underscoring the need to investigate comorbidities in the evaluation of patients with this form of the disease.

MeSH terms

  • Adult
  • Algorithms
  • Asthma / diagnosis
  • Asthma / drug therapy
  • Asthma / epidemiology*
  • Asthma / etiology*
  • Brazil / epidemiology
  • Environmental Exposure / adverse effects
  • Environmental Exposure / statistics & numerical data
  • Epidemiologic Methods
  • Female
  • Gastroesophageal Reflux / diagnosis
  • Glucocorticoids / therapeutic use
  • Heart Failure / complications
  • Humans
  • Male
  • Occupational Exposure / adverse effects
  • Occupational Exposure / statistics & numerical data
  • Risk Factors
  • Sinusitis / complications
  • Skin Tests
  • Sleep Apnea, Obstructive / complications
  • Smoking / adverse effects
  • Treatment Failure
  • Treatment Refusal / statistics & numerical data


  • Glucocorticoids