The prevalence of obstructive sleep apnea in patients with difficult-to-treat asthma

Obstructive sleep apnea (OSA) occurs more commonly in asthma patients than in the general population and can complicate asthma management. The aim of this study was to evaluate the presence of OSA in patients with difficult-to-treat asthma (DTA) and to investigate the sleep quality in these patients.

Patients with DTA were recruited from the adult allergy clinic of a tertiary care hospital. After completing the Sleep Questionnaire and Epworth Sleepiness Scale, all participants underwent overnight polysomnography. The demographic and asthma severity assessments included the following measures: the age at diagnosis, duration of illness, smoking and atopy status, results of pulmonary function tests, number of asthma control medications used, and number of hospitalizations and emergency room visits because of asthma and analgesic hypersensitivity according to apnea-hypopnea index (AHI) scores.

We analyzed 47 (M:9/F:38) DTA patients with a mean age of 48.74±9.45 years. The mean duration of asthma was 9.17±6.5 years. Twenty-four (51.1%) patients were atopic. The analgesic hypersensitivity rate was 27.7%. Fourteen patients (29.8%) were former smokers and 2 patients were current smokers. Sleep quality was impaired in all patients. Thirty-five patients (74.5%) had OSA, 11 of whom had mild OSA, and 24 patients had moderate-severe OSA. The presence of OSA was not statistically correlated with asthma characteristics.

The study showed that there is a remarkably high prevalence of OSA in DTA. Although no statistically significant relationship between the presence of OSA and clinical asthma characteristics was identified, all DTA patients should be assessed for OSA.