Obstructive Sleep Apnea (OSA)
In the spectrum ranging from snoring to respiratory event related arousals (RERAs) to OSA, OSA is the most pathologic. In a study with 63 children and adolescents with CF between the ages of 2 and 14 years, the prevalence of polysomnogram-identified OSA has been reported to be 55.6%.47 Similarly, a study by Spicuzza et al. demonstrated that 70% of the 40 children between the age of 6 months and 11 years with stable CF had OSA.13 Of note, in children without underlying lung disease, the prevalence of OSA has been reported to be 1% to 4%.8 Although both groups of children with OSA share common factors such as adenotonsillar hypertrophy, craniofacial abnormalities such as micrognathia or midfacial hypoplasia, the children with CF have increased chronic rhinosinusitis (CRS).8,47 Increased respiratory resistance and hypoventilation related to acute and chronic inflammation has been cited as a potential mechanism for upper airway obstruction.48
To our knowledge, there are no studies specifically examining the relationship between CF related CRS and OSA, however the literature surrounding non-CF CRS and OSA can be extrapolated to CF related CRS. CRS has been shown to be strongly associated with poor subjective sleep quality and unequivocally associated with OSA.49-51With respect to the latter, Jiang et al found that up to 64.7% of adult patients with CRS had comorbid OSA on polysomnography (PSG).49 In contrast, Alt et al identified OSA in only 15% of adult patients with CRS.50 Mahdavinia et al. examined how CRS affects polysomnography findings in patients with comorbid OSA. They compared patients with both CRS and OSA to patients with OSA and without CRS, and found that the AHI (Apnea-Hypopnea Index )between the two groups was similar suggesting that CRS may not significantly impact AHI.52 The effect of CRS, if any, on OSA has been theorized to be related to increased nasal airway resistance and sequelae of chronic inflammation.53 It has also been posited that chronic post-nasal drainage associated with sino-nasal inflammation can induce inflammatory, obstructive changes in the upper airway including the soft palate and uvula.52
OSA is not known to be as common in adults as in the pediatric population with CF. In a cross-sectional study with 51 stable CF adults (mean age 25.1 years), only two CF patients (3.9%) met the standard criteria for OSA.5 One major study in a non-CF population has reported prevalence rates in men and women as high as 24% and 9% respectively.8 Studies with adult CF patients have been limited due to the sample size, lack of diversity, lack of an older age group which potentially underestimates the prevalence.5