Independent Association Between Oxygen Desaturation Index and Cardiovascular Disease in Non-Sleepy Sleep-Disordered Breathing Subtype: A Chinese Community-Based Study

Abstract

Purpose

Non-sleepy sleep-disordered breathing (SDB) is increasingly recognized as an important clinical subtype. The association between non-sleepy SDB and cardiovascular disease (CVD) is not well understood. Our objectives were to investigate the relationship between non-sleepy SDB and CVD and determine which nocturnal hypoxia parameter most strongly reflects this association in a large community population.

Patients and Methods

Cross-sectional data from 3626 randomly-selected Chinese community-dwelling participants who underwent overnight type IV sleep monitoring were analyzed. Parameters of nocturnal hypoxemia were extracted from sleep monitoring devices, including mean nocturnal oxygen saturation, lowest oxygen saturation, oxygen desaturation index (ODI), and time with oxygen saturation <90%. An ODI ≥7.0 events/h was considered to signify SDB. An Epworth Sleepiness Scale score of 10 or less indicated no sleepiness.

Results

The SDB rate was 30.7% (1114/3626), of which 96.5% (1075/1114) were considered the non-sleepy SDB subtype. ODI, typical nocturnal intermittent hypoxia indicator for SDB, was independently related to CVD, regardless of whether excessive daytime sleepiness was present. After adjusting for confounders, ODI most strongly reflected the association between non-sleepy SDB and CVD (OR:1.023; 95% CI:1.003–1.043). We observed a nonlinear association between ODI and the prevalence of CVD, where the likelihood of CVD increased with ODI≥10 events/h and a markedly increasing trend was observed with ODI ≥20 events/h (reference ODI = 7.0 events/h). Metabolic parameters, Pittsburgh Sleep Quality Index, and inflammatory marker did not mediate the association between ODI and CVD in the non-sleepy SDB subtype.

Conclusion

In the Chinese community-dwelling population, non-sleepy SDB was highly prevalent. ODI, an easily extracted indicator from a type IV sleep monitor, most strongly reflected the association between non-sleepy SDB and CVD.

Keywords:

• oxygen desaturation index
• cardiovascular disease
• non-sleepy
• sleep-disordered breathing
• community-based general population

Abbreviations

AHI, apnea-hypopnea index; BMI, body mass index; CHO, total cholesterol; CI, confidence interval; CVD, cardiovascular disease; EDS, excessive daytime sleepiness; ESS, Epworth Sleepiness Scale; HDL-C, high-density lipoprotein cholesterol; hsCRP, high-sensitivity C-reactive protein; LDL-C, low-density lipoprotein cholesterol; MeanSpO₂, mean oxygen saturation; MinSpO₂, lowest nocturnal oxygen saturation; ODI, oxygen desaturation index; OR, odds ratio; PSQI, Pittsburgh Sleep Quality Index; SDB, sleep-disordered breathing; T90%, percentage of sleep time with SpO₂ <90%; TG, triglycerides.

Data Sharing Statement

The study data are available from the corresponding author upon reasonable request.

Acknowledgments

We thank all of the individuals who participated in this study.

Disclosure

The authors report no conflicts of interest.

Additional information

Funding

This research was supported by the National Natural Science Foundation of China (Grant No. 82170098, 81870077) to Qiong Ou and CAMS Innovation Fund for Medical Sciences (CIFMS, Grant No. 2020-I2M-2-009) to Guangliang Shan.