Currently, there are controversies about the relationship between OSA and subjective sleepiness. Recent study has shown the correlation between subjective sleep complaints and respiratory arousal. However, there is limited information on the relationship between subjective sleep perceptions and objective sleep parameters in different patient populations.
A retrospective study was performed in patients with obstructive sleep apnea. All patients completed post-test questionnaire after sleep study as part of our routine procedure. Any patients with significant neurological diseases, psychiatric disorder, central sleep apnea, severe periodic leg movements (PLMI>50) or incomplete records were excluded from the study.
79 patients met the criteria for entry into analysis; 41 African American (B) and 38 Caucasian (W). The average age is 47.5±10.1 years and the mean apnea-hypopnea index (AHI) is 25.9±19.5 per hour. There was no difference between age, sex, BMI or AHI between two groups. The subjective feeling upon awakening (Question 15 (Q15); scale 1-6) correlated with the arousal index (r=0.27, P=0.019), AHI (r=0.3, P=0.008), and apnea-hypopnea related arousal (r=0.24, P=0.038). There is a tendency toward significant correlation between subjective sleep quality (Question 7 (Q7), scale 1-4) and arousal index (r=0.22, P=0.054) as well as between Q7 and AHI (r=0.22, P=0.056). The subgroup analysis revealed a significant correlation between Q15 and arousal index only in African American population (r=0.36, P=0.02 [B] versus r=0.17, P=NS [W]). However, Q15 correlated with AHI only with Caucasian population (r=0.20, P=NS [B] versus r=0.46 P<0.01 [W]).
It is concluded that subjective perception from post-sleep questionnaire correlates significantly with severity of apnea and frequency of arousals especially respiratory arousals. The subjective perception correlates only with the frequency of arousals in African American population, while subjective perception of Caucasian population correlates directly with severity of apnea.
It is speculated that other factors in addition to apnea may play a role in sleep disruption in African American population with sleep apnea. However, more studies are needed.
Cynthia Crowder, None.