Factors affecting fatigue severity in patients with obstructive sleep apnea

Abstract

OBJECTIVES: A limited number of studies have investigated the relationships among fatigue, insomnia and obstructive sleep apnea (OSA). This study evaluated the factors affecting fatigue severity in patients with OSA. METHODS: We investigated 633 OSA patients who were diagnosed by polysomnography. All patients completed sleep questionnaires including self-reported sleep duration, the Fatigue Severity Scale (FSS), the Korean version of Epworth Sleepiness Scale (K-ESS), Insomnia Severity Index (ISI), Korean version of Pittsburgh Sleep Quality Index (K-PSQI) and Beck Depression Inventory-2 (BDI-2). RESULTS: The subjects had a mean age of 48.7 ± 10.5 years and 72.5% (n = 459) were men. The subjects were distributed as follows: 160 with mild, 168 with moderate and 305 with severe OSA. A multiple regression model found that age (β = -0.146, P = .005), K-ESS (β = 0.689, P < .001), 8 ≤ ISI score < 15 (β = 3.801, P = .006), 15 ≤ ISI score (β = 4.565, P = .009), and K-PSQI (β = 0.684, P = .002) were predictors of a higher FSS score. BDI-2 (β = 0.007, P = .918), apnea-hypopnea index (AHI) (β = -0.006, P = .895), arousal index (β = 0.034, P = .415), and nadir O(2) saturation (β = -0.044, P = .655) were not associated with FSS score. CONCLUSION: Our findings indicate that fatigue severity is more likely to be associated with younger age, sleepiness and insomnia, but less likely to be directly related to OSA severity.