Does airway surgery lower serum lipid levels in obstructive sleep apnea patients? A retrospective case review

International Consensus Statement on Obstructive Sleep Apnea

BACKGROUND

Evaluation and interpretation of the literature on obstructive sleep apnea (OSA) allows for consolidation and determination of the key factors important for clinical management of the adult OSA patient. Toward this goal, an international collaborative of multidisciplinary experts in sleep apnea evaluation and treatment have produced the International Consensus statement on Obstructive Sleep Apnea (ICS:OSA).

METHODS

Using previously defined methodology, focal topics in OSA were assigned as literature review (LR), evidence-based review (EBR), or evidence-based review with recommendations (EBR-R) formats. Each topic incorporated the available and relevant evidence which was summarized and graded on study quality. Each topic and section underwent iterative review and the ICS:OSA was created and reviewed by all authors for consensus.

RESULTS

The ICS:OSA addresses OSA syndrome definitions, pathophysiology, epidemiology, risk factors for disease, screening methods, diagnostic testing types, multiple treatment modalities, and effects of OSA treatment on multiple OSA-associated comorbidities. Specific focus on outcomes with positive airway pressure (PAP) and surgical treatments were evaluated.

CONCLUSION

This review of the literature consolidates the available knowledge and identifies the limitations of the current evidence on OSA. This effort aims to create a resource for OSA evidence-based practice and identify future research needs. Knowledge gaps and research opportunities include improving the metrics of OSA disease, determining the optimal OSA screening paradigms, developing strategies for PAP adherence and longitudinal care, enhancing selection of PAP alternatives and surgery, understanding health risk outcomes, and translating evidence into individualized approaches to therapy.

Obstructive Sleep Apnoea and Lipid Metabolism: The Summary of Evidence and Future Perspectives in the Pathophysiology of OSA-Associated Dyslipidaemia

Obstructive sleep apnoea (OSA) is associated with cardiovascular and metabolic comorbidities, including hypertension, dyslipidaemia, insulin resistance and atherosclerosis. Strong evidence suggests that OSA is associated with an altered lipid profile including elevated levels of triglyceride-rich lipoproteins and decreased levels of high-density lipoprotein (HDL). Intermittent hypoxia; sleep fragmentation; and consequential surges in the sympathetic activity, enhanced oxidative stress and systemic inflammation are the postulated mechanisms leading to metabolic alterations in OSA. Although the exact mechanisms of OSA-associated dyslipidaemia have not been fully elucidated, three main points have been found to be impaired: activated lipolysis in the adipose tissue, decreased lipid clearance from the circulation and accelerated de novo lipid synthesis. This is further complicated by the oxidisation of atherogenic lipoproteins, adipose tissue dysfunction, hormonal changes, and the reduced function of HDL particles in OSA. In this comprehensive review, we summarise and critically evaluate the current evidence about the possible mechanisms involved in OSA-associated dyslipidaemia.

[Effect of smoking on glucose, lipid metabolism and sleep structure in postoperative patients with obstructive sleep apnea]

Objective:The aim of this study is to investigate the effect of smoking on the glucose, lipid metabolism and sleep structure in patients with moderate and severe obstructive sleep apnea （OSA） after operation. Methods:A retrospective analysis of 103 adult male patients with moderate to severe OSA who were diagnosed and treated from January 2016 to December 2017. All of them could not tolerate continuous positive pressure ventilation. After evaluation by an otolaryngologist, they underwent modified uvulapalatopharyngoplasty surgery. All participants were grouped according to smoking status（non-smokers, smokers） for analysis. Laboratory-based polysomnographic variables, anthropometric measurements, biochemical indicators, and smoking history, Epworth sleepiness score（ESS） were collected preoperatively and postoperatively. And the difference of each variable preoperatively and postoperatively was demonstrated as delta（Δ, calculated as postoperative value minus preoperative value）. Results:Fifteen patients with preoperative moderate OSA and 88 patients with severe OSA. The overall successful rate of surgery was 55.3%（18.4% cured, 23.3% markedly effective and 13.6% effective）, and there was no statistical difference between the non-smokers and the smokers（59.7% vs 48.9%, P=0.276）. After surgery, AHI, mean oxygen saturation, ODI, MAI, TC, FBG, fasting insulin, BMI, ESS, N1 and N3 were significantly improved（P<0.05）. The amelioration of glucose or lipid metabolism related traits（including ΔTC, ΔFBG, Δfasting insulin） were not significantly different between smokers and non-smokers. However, as to sleep structure, ΔN3 was significantly higher in non-smoker as compared to smokers（P=0.039）. Conclusion:Upper airway surgery is helpful to improve the glucose and lipid metabolism disorder and sleep structure in OSA patients. Postoperative smoking was associated with worse sleep structure, but not glycolipid metabolism. The postoperative improvement of sleep structure in non-smoking OSA patients was better than smokers.

Excessive daytime sleepiness, metabolic syndrome, and obstructive sleep apnea: two independent large cross-sectional studies and one interventional study

Background

Obstructive sleep apnea (OSA) and excessive daytime sleepiness (EDS) were considered to contribute to MetS. This study was performed to assess the association between MetS and EDS in two independent large-scale populations, and in subjects who underwent upper-airway surgery.

Methods

A total of 6312 patients without self-reported depression and 3578 suspected OSA patients were consecutively recruited, during health screening examinations and from our sleep center, respectively. A total of 57 subjects with OSA who underwent upper-airway surgery were also included. Demographic, anthropometric, biochemical, and polysomnographic data were obtained.

Results

In the health screening examination group, 233 (9.23%) women and 350 (10.93%) men had complaints of EDS. A total of 229 (7.04%) women and 1182 (36.88%) men met the criteria for MetS. In the OSA group, 147 (21.18%) women and 1058 (36.69%) men reported EDS. In addition, 93 (13.4%) women and 1368 (47.43%) men reported MetS. In the health screening examination group, EDS did not contribute significantly to MetS (OR = 1.125, 95% CI: 0.907–1.395; p = 0.283). In the OSA group, EDS significantly contributed to MetS (OR = 1.249, 95% CI: 1.063–1.468; p = 0.007); however, the results were not significant after adjusting for sleep variables (OR = 1.071, 95% CI: 0.905–1.268; p = 0.423). Upper-airway surgery did not affect cardio-metabolic variables in OSA patients with or without EDS.

Conclusions

EDS was not associated with MetS in two independent large-scale cohorts. In addition, upper-airway surgery did not affect components of MetS in OSA patients with and without EDS.