Maximizing Sleep Health: A New Approach for Testing Comorbid Insomnia and Sleep Apnea

Comorbid insomnia and sleep apnea (COMISA) is a double whammy for sleep. People with COMISA experience both insomnia, the difficulty falling or staying asleep, and sleep apnea, where breathing repeatedly stops and starts during sleep. These disorders worsen each other, creating a vicious cycle of poor sleep and daytime fatigue. This study delves into the intricate relationship between these conditions. We analyzed data from over 3,300 home sleep tests to see how sleep apnea severity impacts sleep maintenance in individuals with COMISA.

Our unique approach involved using longitudinal home sleep tests, meaning participants took the tests over multiple nights. This allowed us to assess various sleep metrics associated with comorbid insomnia, particularly focusing on how well people with sleep apnea maintain sleep throughout the night. With a large dataset, we explored how OSA severity, measured by two key indicators - the apnea/hypopnea index (AHI) and hypoxic burden (HB) - influences sleep parameters like total sleep time and the number of awakenings during the night.

The findings paint a clear picture: even mild sleep apnea disrupts sleep. As sleep apnea severity increased, people experienced less total sleep time and more frequent awakenings. This highlights the critical role of addressing sleep apnea to improve sleep quality for those struggling with COMISA.
   
COMISA represents a complex interplay of sleep disorders, with each exacerbating the symptoms and severity of the other. In this study, we delved into the intricate relationship between obstructive sleep apnea (OSA) and insomnia, utilizing a unique longitudinal approach to assess metrics associated with comorbid-insomnia, particularly focusing on sleep maintenance, among individuals undergoing home sleep tests. With a substantial dataset comprising 3,370 tests from 1,358 participants, our investigation aimed to elucidate how OSA severity, measured by the apnea/hypopnea index (AHI) and hypoxic burden (HB), influences various parameters of comorbid insomnia.

The results of our analysis unveiled compelling associations between OSA severity and comorbid-insomnia measures, underscoring the pervasive impact of sleep apnea on sleep continuity and quality. Notably, as AHI severity increased, total sleep time (TST) and sleep efficiency (SE) decreased, while wake after sleep onset (WASO) and the number of awakenings (#W) escalated. These findings suggest a dose-response relationship between OSA severity and comorbid insomnia, with even mild forms of sleep apnea significantly affecting sleep maintenance. Furthermore, the positive correlation between AHI, HB, and comorbid-insomnia metrics highlights the intertwined nature of these sleep disorders, emphasizing the need for comprehensive assessment and targeted interventions to address COMISA effectively.

COMISA is a debilitating disorder marked by a bi-directional relationship between obstructive sleep apnea (OSA) and insomnia. To explore this relationship, we employed a novel approach to evaluate metrics associated with comorbid-insomnia (sleep maintenance) in individuals who tested for OSA with a longitudinal (multi-night) home sleep test.
 

Methods

3,370 tests were evaluated (1,358 participants; mean age 49.73 years, SD 15.0; mean tests/participant 3.1, SD 4.5). OSA was measured by apnea/hypopnea index (AHI) and hypoxic burden (HB). ANOVA and PCC (99% CI) were used to evaluate the relationship between SA severity and measures of comorbid-insomnia (total sleep time (TST), sleep efficiency (SE), wake after sleep onset (WASO), #awakenings (#W), %light sleep (%L), %REM sleep (%REM)).


Results

TST (F[3,3357]=5.21; p<0.001), SE (F[3,3357]=16,12; p<0.001), and %REM (F[3,3357]=2.84; p=0.014) decreased, and #W (F[3, 3357]=3.20; p<0.001), WASO (F[3, 3357]=15.22; p<0.0001) and %Light (F[3,3357]=3.40; p<0.0001) increased with AHI severity. Between normal (AHI 0-4.99) and mild (AHI 5-14.99) tests, SE (-2%; p=0.005) decreased, and #W (+1.05; p=0.01) and WASO (+10.3 min; p<0.0001) increased. The largest change occurred between normal and severe (AHI >30) tests (TST -28.65 min; WASO +27.15 min). AHI and HB were positively correlated (r=0.67; p<0.0001). AHI was weakly, but significantly, correlated with TST (p<0.0001), SE (p<0.0001), #W (p<0.0001), and WASO (p<0.0001). HB was correlated with SE (p<0.0001), #W (p<0.0001), and WASO (p<0.0001). 


Conclusion 

Comorbid-insomnia measures increased with SA severity at all levels, suggesting that the presence of OSA at any severity is a risk factor for COMISA. Further analysis is required to determine if the presence of SA and the impact of HB are the primary factors driving COMISA. Contextual issues surrounding the sleep period need to be addressed.