The effect of continuous positive airway pressure on circulating malondialdehyde among obstructive sleep apnea patients: a meta-analysis.

BACKGROUND: Obstructive sleep apnea (OSA) has been demonstrated to be associated with an increase of oxidative stress. However, whether circulating malondialdehyde (MDA), a widely used biomarker of oxidative stress, could be reduced by the treatment of OSA by continuous positive airway pressure (CPAP) is debated. The present meta-analysis was performed to determine the effect of CPAP treatment on circulating MDA among patients with OSA. METHODS: A systematic search of PubMed, Embase, and Web of Science was performed for literature covering the period between 1967 and August 2019. Standardized mean difference (SMD) was calculated to estimate the treatment effects of pre- and post-CPAP therapy. RESULTS: A total of 10 studies with 220 patients were included in this meta-analysis. A significant decrease in circulating MDA was observed after CPAP treatment (SMD = 1.164, 95% CI = 0.443 to 1.885, z = 3.16, p = 0.002) in OSA patients. Subgroup analyses revealed that CPAP therapy was associated with a significant decrease of circulating MDA in elder (SMD = 1.629, 95% CI = 0.265 to 2.994, z = 2.34, p = 0.019), more obese patients (SMD = 0.954, 95% CI = 0.435 to 1.473, z = 3.61, p = 0.000), more severe OSA patients (SMD = 0.879, 95% CI = 0.421 to 1.336, z = 3.76, p = 0.000), patients with therapeutic duration ≥ 3 months (SMD = 1.867, 95% CI = 0.563 to 3.172, z = 2.80, p = 0.005), and patients with good compliance (SMD = 1.004, 95% CI = 0.703 to 1.305, z = 6.54, p = 0.000). CONCLUSIONS: This meta-analysis suggested that CPAP therapy exerted significant lowering effects on circulating MDA, especially in elder, more obese, and more severe OSA patients and patients with good compliance as well as longer duration of CPAP application.

Association between sleep apnea and ultrasound-defined liver fibrosis: Results from NHANES 2017 to 2020.

Liver fibrosis is a critical factor in the advancement of nonalcoholic fatty liver disease towards cirrhosis. There is limited research exploring the association between obstructive sleep apnea (OSA) and liver fibrosis among community populations. The present study aimed to assess the association between sleep apnea (SA) and liver fibrosis based on the National Health and Nutrition Examination Survey (NHANES). Data were acquired from NHANES survey cycle 2017 to 2020. We assessed liver fibrosis by the median values of liver stiffness measurement (LSM). The diagnosis of SA was based on participants' response to sleep questionnaire. Univariate and multivariate logistic regression were used to validate the association of SA and liver fibrosis. A total of 7615 participants were included in this study. The LSM level of SA group was significantly higher than non-SA group. The proportion of liver fibrosis in SA group was markedly higher than that in non-SA group (14.0% vs 7.3%, P < .001). Univariate logistic analysis showed that SA was positively associated with liver fibrosis (OR = 2.068, 95%CI = 1.715-2.494, P < .001). Further multivariate logistic analysis revealed that SA was independently associated with increased risk of liver fibrosis after adjusting for confounding factors (OR = 1.277, 95%CI = 1.003-1.625, P = .048). The current study demonstrated an independent association between self-reported SA and increased risk of ultrasound-defined liver fibrosis in community-based sample.

The relationship between obstructive sleep apnea and circulating tau levels: A meta-analysis.

BACKGROUND: Alzheimer's disease (AD) is an irreversible, progressive brain disorder that impairs memory, thinking, language, and, eventually, the ability to carry out the simplest of tasks. Tau protein, the major component of neurofibrillary tangles, is considered a key mediator of AD pathogenesis. The association between obstructive sleep apnea (OSA) and circulating tau remains unclear. The aim of the present meta-analysis was to evaluate the relationship between OSA and circulating tau via quantitative analysis. METHODS: A systematic search of Pubmed, Embase, and Web of Science were performed. The mean values of circulating total tau (T-tau) and phosphorylated tau (P-tau) in OSA and control groups were extracted. Standardized mean difference (SMD) with 95% confidence interval (CI) was calculated by using a random-effect model or fixed-effect model. RESULTS: A total of seven studies comprising 233 controls and 306 OSA patients were included in this study. The meta-analysis showed that the circulating T-tau level was significantly higher in OSA patients than those in the control group (SMD = 1.319, 95% CI = 0.594 to 2.044, z = 3.56, p < .001). OSA patients also had significantly higher circulating P-tau level than control group (SMD = 0.343, 95% CI = 0.122 to 0.564, z = 3.04, p = .002). CONCLUSIONS: The present meta-analysis demonstrated that both circulating T-tau and P-tau levels were significantly increased in OSA subjects when compared with non-OSA subjects. Larger sample-size studies on the association between OSA and circulating tau are still required to further validate our results.

Validation of fatty liver index and hepatic steatosis index for screening of non-alcoholic fatty liver disease in adults with obstructive sleep apnea hypopnea syndrome.

BACKGROUND: Obstructive sleep apnea hypopnea syndrome (OSAHS) is a contributing factor for non-alcoholic fatty liver disease (NAFLD). Non-invasive algorithms including fatty liver index (FLI) and hepatic steatosis index (HSI) have been used as a screening test for NAFLD in epidemiologic studies. The aim of this study is to compare the diagnostic accuracy of FLI and HSI for NAFLD detection in adults with OSAHS. METHODS: We enrolled consecutive adult subjects who were newly diagnosed with OSAHS from March 2016 to January 2018. NAFLD was diagnosed by ultrasonography. The accuracy and cut-off point of the FLI and HSI to detect NAFLD were assessed by analyzing the area under the receiver operating characteristic (AUROC) curve and the maximum Youden index analysis, respectively. RESULTS: The 326 subjects were diagnosed as NAFLD according to ultrasound findings, while 105 subjects who had normal abdominal ultrasonography were grouped as controls. Both FLI and HSI values were significantly higher in patients with NAFLD compared with controls. The AUROC of FLI and HSI for predicting NAFLD was 0.802 (95% confidence interval [CI] 0.762-0.839) and 0.753 (95% CI 0.710-0.793), respectively. The AUROC of FLI was significantly higher than that of HSI (P = 0.0383). The optimal cut-off value of FLI and HSI was 60 (sensitivity 66% and specificity 80%) and 35 (sensitivity 81% and specificity 60%), respectively. CONCLUSIONS: Both FLI and HSI can serve as screening tools for NAFLD in OSAHS adults. The FLI shows better performance in diagnosing NAFLD than HSI. TRIAL REGISTRATION: Chinese Clinical Trial Registry (No. ChiCTR-OOB-15007253), http://www.chictr.org.cn/showproj.aspx?proj=11606.

Effect of continuous positive airway pressure on liver enzymes in obstructive sleep apnea: A meta-analysis.

BACKGROUND: Previous studies have suggested that obstructive sleep apnea (OSA) was associated with nonalcoholic fatty liver disease (NAFLD). However, the impact of OSA treatment using continuous positive airway pressure (CPAP) on liver enzymes remained controversial. This meta-analysis was conducted to determine whether CPAP therapy could reduce liver enzyme levels. METHODS: Two reviewers independently searched PubMed, Cochrane library, Embase and Web of Science before December 2015. Information on characteristics of subjects, study design and pre- and post-CPAP treatment of serum ALT and AST was extracted for analysis. A total of five studies with seven cohorts that included 192 patients were pooled into meta-analysis. RESULTS: CPAP was associated with a statistically significant decrease on both ALT and AST levels in OSA patients (WMD = 8.036, 95% CI = 2.788-13.285, z = 3.00, P = .003 and WMD = 4.612, 95% CI = 0.817-8.407, z = 2.38, P = .017, respectively). Subgroup analyses indicated that CPAP therapy was more effective in OSA patients with treatment duration > 3 mo (WMD = 12.374, 95% CI = 2.727-22.020, z = 2.51, P = .012 for ALT and WMD = 7.576, 95% CI = 1.781-13.370, z =2.56, P = .010 for AST). CONCLUSION: This meta-analysis suggested that CPAP was associated with a statistically significant decrease on liver enzymes in OSA patients. Further large-scale well-designed RCTs with long-term follow-up are required to clarify this issue.