Lower Lung Function and Bronchiectasis in Cystic Fibrosis Increases the Risk of Obstructive Sleep Apne

Abstract

PURPOSE: To determine if cystic fibrosis (CF) patients with severe obstructive lung disease have a higher prevalence of obstructive sleep apnea (OSA). METHODS: Charts of 25 hospitalized pediatric CF patients were reviewed. Chest x-ray/CT scan to determine presence of bronchiectasis and spirometry to determine the lowest lung function during the past year. Degree of severity was based on forced expiratory volume in 1 second (FEV 1) from the ATS/ERS task force standardization of lung function testing. Patients were divided into 2 groups as follows: mild and moderate (level I) vs. moderate-severe, severe, very severe (level II). Level I severity was a FEV1 greater than or equal to 60% predicted and level II was less than or equal to 59% predicted. The hospitalized CF patients were screened for OSA with the Pediatric Sleep Questionnaire. ItaTMs a validated questionnaire with a sensitivity of 0.85 and a specificity of 0.87 when 8 or more answers of the 22 question-items are abnormal. The relationship between lung function and OSA was assessed using contingency table analysis (Fisher's exact test). RESULTS: 12 patients (48%) screened positive for OSA. 21 patients (84%) had bronchiectasis. 15 patients (60%) had level II lung function. No statistically significant association was found between lung function severity level and OSA. 40% of level I patients with OSA compared to 53.3% of level II patients (p=0.688). When stratified for bronchiectasis (Yes or No), among those with bronchiectasis, 0% of severity level I patients compared to 53.3% of level II patients had OSA (low-bias estimate of relative risk 3.733, 95% CI 0.164-0.902, p=0.046). CONCLUSIONS: This study indicates that the prevalence of OSA is higher in hospitalized pediatric CF patients (48%) compared to the general pediatric population (0.7-10.3%). The CF patients with bronchiectasis have a significant association between lung function severity level and OSA. There is a higher percentage of OSA in the severely obstructed group (level II).