Parameters affecting improvement of excessive daytime sleepiness in obstructive sleep apnea patients

Abstract

ObjectivesObstructive sleep apnea (OSA) is a sleep-related breathing disorder caused by repetitive obstruction of the upper airway; this impairs gaseous exchange, resulting in hypoxia, hypercapnia, and frequent arousals. Excessive daytime sleepiness (EDS) is a common daytime symptom of OSA. EDS manifests as fatigue and impaired attention, leading to poor performance at work and falling asleep while driving, which is a major socioeconomic problem. Therefore, it is important to properly treat EDS and accurately predict the response to treatment. However, few studies have compared OSA patients showing and not showing improvement in EDS. Therefore, this study aimed to objectively analyze and compare EDS improvement and non-improvement groups. Subjects and methodsWe retrospectively reviewed the medical records of 57 OSA patients with EDS. Patients were divided into two groups according to the improvement in EDS after positive airway pressure (PAP) device treatment. We analyzed differences in clinical records including patients' age, sex, history of smoking, hypertension, diabetes, myocardial infarction, and cerebrovascular disease between the two groups. Systolic, diastolic blood pressure, blood test including blood glucose, total cholesterol, high- and low-density lipoprotein cholesterol, and triglyceride levels were also analyzed. Polysomnography (PSG) data, PAP device treatment compliance and scores of questionnaires related to various psychiatric symptoms, subjective sleep quality between the two groups were also analyzed. ResultsThere was no statistically significant difference in age, gender, or past medical history between the two groups. Systolic and diastolic blood pressure, and blood test results, were also not significantly different. Among the questionnaires related to various psychiatric symptoms, the groups showed statistically significant differences in Social Avoidance and Distress Scale (SADS) and Fear of Negative Evaluation (FNE) scores (P = 0.001 and 0.020, respectively). The group differences in the scores on the other questionnaires were not significantly different. Among the PSG items, significant group differences were observed in the percentage of stage 2 non-REM sleep (N2%, P = 0.023), apnea index (AI, P = 0.005), apnea-hypopnea index (AHI, P = 0.023), and frequency of 3 % oxygen desaturation (ODI3, P = 0.001). No obesity-related parameters showed significant group differences. The percentage of days on which a PAP device was used (out of 90 days; PAP%) and percentage of days on which a PAP device was used for >4 h (Time4%) did not differ significantly. ConclusionsThe SADS, FNE, AI, AHI, N2%, and ODI3 parameters differed significantly between the EDS improvement and non-improvement groups. These parameters may help clinicians treat and predict the prognosis of patients suffering with EDS.