Investigation of factors associated with difficult-to-control asthma

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

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.

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.

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.