Major factors affecting severity of obstructive sleep apnea

Utility of acoustic pharyngometry for screening of obstructive sleep apnea

OBJECTIVE

To determine whether combining acoustic pharyngometric parameters with cephalometric and clinical parameters could improve the predictive power for significant obstructive sleep apnea (OSA) in a Korean population.

METHODS

A total of 229 consecutive adult patients with suspected OSA were enrolled. The predictability for significant OSA using acoustic pharyngometric or cephalometric parameters or combining these parameters and clinical factors was calculated and compared using multivariate logistic regression and receiver operating characteristic (ROC) curves.

RESULTS

In multivariate logistic regression, age, sex, minimum upper airway cross-sectional area (UA-CSA), and mandibular plane to hyoid distance (MPH) were all significant independent predictors of significant OSA. The minimum UA-CSA of 0.85 cm² provided fair discrimination for OSA [area under the curve (AUC): 0.60, 95% confidence interval (CI): 0.52-0.67]. The MPH of 18.75 mm provided fair discrimination for OSA (AUC; 0.65, 95% CI: 0.58-0.72). The discriminative ability of the final model of multivariate ROC curve analyses that included the minimum UA-CSA, age, sex, body mass index (BMI), and MPH was better than the minimum UA-CSA alone (AUCs: 0.77 vs. 0.60). Optimal cut-off values of predictors for discriminating significant OSA were as follows: male for sex, 40 years for age, 25.5 kg/m² for BMI, 1.06 cm² for minimum UA-CSA, and 18 mm for MPH.

CONCLUSION

Minimum UA-CSA measured using acoustic pharyngometry while sitting might be a useful method to predict OSA. Combining minimum UA-CSA with age, sex, BMI and MPH improved the predictive value for significant OSA.

Factors associated with undiagnosed obstructive sleep apnoea among hypertensive patients: A multisite cross-sectional survey study in Taiwan

AIMS AND OBJECTIVES

To investigate the distribution and risk factors associated with undiagnosed obstructive sleep apnoea among hypertensive patients.

BACKGROUND

Obstructive sleep Apnoea has been deemed a cardinal risk factor affecting cardiovascular event, and the condition is still frequently overlooked clinically. The lack of advanced diagnosis often causes hypertensive patients with obstructive sleep apnoea to miss opportunities for preventing chronic diseases.

DESIGN

A cross-sectional design.

METHODS

A total of 215 hypertensive participants were recruited from the cardiovascular outpatients of medical centre in northern and middle Taiwan. The Chinese version of Pittsburgh Sleep Quality Index, the Chinese version of the Epworth Sleep Scale and a portable sleep monitoring device were used for data collection. Logistic regression analysis was conducted to identify the factors affecting hypertensive patients with obstructive sleep apnoea, and a multinomial logistic regression analysis was used to examine the major influence factors for each obstructive sleep apnoea severity level.

RESULTS

81.9% of the hypertensive participants were found having obstructive sleep apnoea. Concerning to the obstructive sleep apnoea severity, 50.0% of participants had mild obstructive sleep apnoea. After controlling the confounding variables, the supine position (odds ratio, 1.04; 95% CI, 1.01-1.07), SO₂ (odds ratio, 0.58; 95% CI, 0.38-0.89) and oxygen desaturation index (odds ratio, 2.70; 95% CI, 1.18-6.18) were significantly associated with obstructive sleep apnoea. Furthermore, severe obstructive sleep apnoea was significantly correlated with gender (odds ratio, 0.04; 95% CI, 0.00-0.66), excessive daytime sleepiness (odds ratio, 20.27; 95% CI, 1.58-26.97) and oxygen desaturation index (odds ratio, 4.05; 95% CI, 1.86-8.81).

CONCLUSIONS

Nearly 82% of the hypertensive participants were found having undiagnosed obstructive sleep apnoea, and 80% of them were mild or moderate severity. Oxygen desaturation index, SO₂ and the supine position were found to be major predictors for obstructive sleep apnoea. Remarkably, oxygen desaturation index was the most significant predictor for mild, moderate and severe obstructive sleep apnoea.

RELEVANCE TO CLINICAL PRACTICE

Healthcare providers should enhance their sensitivities to hypertensive patients at a high risk for obstructive sleep apnoea by actively assessing common obstructive sleep apnoea symptoms and providing strategies to alleviate obstructive sleep apnoea symptoms.

A retrospective study: does upper airway morphology differ between non-positional and positional obstructive sleep apnea?

Objective

The objective of this study was to explore the differences in upper airway morphology between positional (POSA) and non-positional (NPOSA) obstructive sleep apnea.

Methods

This retrospective study enrolled 75 patients (45 NPOSA and 30 POSA) who underwent polysomnography (PSG) and computed tomography (CT). The differences in, and relationships of, the PSG values and CT data between POSA and NPOSA were analyzed.

Results

Significant (p < 0.05) differences between the two groups were found in the apnea/hypopnea index (AHI), lateral-AHI (L-AHI), soft palate length (SPL), cross-sectional palatopharyngeal area, and the coronal diameter (CD) of the palatopharyngeal area at the narrowest part of the glossopharynx, which were all higher in POSA, except for SPL, AHI, and L-AHI. L-AHI was correlated with the cross-sectional area (r =  − 0.306, p = 0.008) and CD (r =  − 0.398, p < 0.001) of the palatopharyngeal area, the cross-sectional area (r =  − 0.241, p = 0.038) and CD (r =  − 0.297, p = 0.010) of the narrowest level of the glossopharynx, the CD of the glossopharynx (r = 0.284, p = 0.013), body mass index (BMI, r = 0.273, p = 0.018), SPL (r = 0.284, p = 0.014), and vallecula-tip of tongue (r = 0.250, p = 0.030). The SPL and CD at the narrowest part of the glossopharynx were included in the simplified screening model.

Conclusions

In NPOSA, the CD of the upper airway was smaller, and the soft palate was longer, than in POSA. These differences may play significant roles in explaining the main differences between NPOSA and POSA.

Genetically-reduced serum ACE activity might be a causal risk factor for obstructive sleep apnea syndrome: A meta-analysis

We meta-analytically summarized the associations of angiotensin converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism with ACE activity and obstructive sleep apnea syndrome (OSAS) to see whether ACE activity is causally associated with OSAS. Literature search and data abstraction were done in duplicate. Sixteen articles including 2060 OSAS patients and 1878 controls were summarized. Overall, no significance was observed for the association of I/D polymorphism with OSAS, whereas carriers of II genotype (weighted mean difference or WMD, 95% confidence interval or CI, P: −11.976, −17.168 to −6.783, <0.001) or I allele (−9.842, −14.766 to −4.918, <0.001) had a lower level of serum ACE activity compared with DD genotype carriers, respectively. In subgroup analyses, carriers of II genotype were 3.806 times more likely to develop OSAS (95% CI, P: 1.865 to 7.765, <0.001) in OSAS patients with hypertension, without heterogeneity. Mendelian randomization analysis indicated there was 37.4% (95% CI: 1.115 to 3.142) and 32.4% (1.106 to 2.845) increased risk of OSAS by a reduction of 1 U/L in ACE activity for the II genotype and I allele carriers versus DD genotype carriers, respectively. There was no observable publication bias. Collectively, genetically-reduced serum ACE activity might be a causal risk factor for OSAS.