Does craniofacial morphology relate to sleep apnea severity reduction following weight loss intervention? A patient-level meta-analysis

Effect of Weight Loss on the Apnea Hypopnea Index is Related to Waist Circumference in Chinese Adults with Overweight and Obesity

Purpose

The present study aimed to evaluate the efficiency of traditional anthropometric and body composition parameters in predicting apnea hypopnea index (AHI) change after weight loss.

Patients and Methods

Chinese adults with overweight and obesity were included into this study containing two parts. A cross-sectional study was conducted in 137 individuals using the baseline data from two weight loss intervention trials. The second part was the weight-loss intervention study conducted in 60 overweight and obese patients with obstructive sleep apnea (OSA). All participants underwent physical examination, bioelectrical impedance analysis and overnight polysomnography. Multivariate linear regression models were used to identify the most accurate parameters to predict AHI and the mediation analysis to evaluate the mediators between weight loss and AHI reduction.

Results

Waist circumference (WC), body mass index and fat mass were positively associated with AHI after adjusting multiple collinearities in the cross-sectional study. After weight-loss intervention, body weight decreased from 94.6 ± 15.3 to 88.0 ± 13.9 kg, and AHI decreased from 41.9 (13.0,66.9) to 20.7 (8.7,51.2) events/h. Among these parameters, only percentage changes in WC and AHI across the intervention were positively intercorrelated after controlling for covariates (adjusted r = 0.271, P = 0.041). The mediation analysis supported WC as a mediator between weight loss and AHI reduction (standardized indirect effect [95% CI] = 4.272[0.936,7.999]).

Conclusion

Both general and abdominal obesity are of high prognostic value for OSA. WC as an easily accessible parameter mediates the effects of weight loss in decreasing OSA severity.

The effect of surgical weight loss on upper airway fat in obstructive sleep apnoea

PURPOSE

Obesity is a reversible risk factor for obstructive sleep apnoea (OSA). Weight loss can potentially improve OSA by reducing fat around and within tissues surrounding the upper airway, but imaging studies are limited. Our aim was to study the effects of large amounts of weight loss on the upper airway and volume and fat content of multiple surrounding soft tissues.

METHODS

Participants undergoing bariatric surgery were recruited. Magnetic resonance imaging (MRI) was performed at baseline and six-months after surgery. Volumetric analysis of the airway space, tongue, pharyngeal lateral walls, and soft palate were performed as well as calculation of intra-tissue fat content from Dixon imaging sequences.

RESULTS

Among 18 participants (89% women), the group experienced 27.4 ± 4.7% reduction in body weight. Velopharyngeal airway volume increased (large effect; Cohen's d [95% CI], 0.8 [0.1, 1.4]) and tongue (large effect; Cohen's d [95% CI], - 1.4 [- 2.1, - 0.7]) and pharyngeal lateral wall (Cohen's d [95% CI], - 0.7 [- 1.2, - 0.1]) volumes decreased. Intra-tissue fat decreased following weight loss in the tongue, tongue base, lateral walls, and soft palate. There was a greater effect of weight loss on intra-tissue fat than parapharyngeal fat pad volume (medium effect; Cohen's d [95% CI], - 0.5 [- 1.2, 0.1], p = 0.083).

CONCLUSION

The study showed an increase in velopharyngeal volume, reduction in tongue volume, and reduced intra-tissue fat in multiple upper airway soft tissues following weight loss in OSA. Further studies are needed to assess the effect of these anatomical changes on upper airway function and its relationship to OSA improvement.

Machine Learning Identification of Obstructive Sleep Apnea Severity through the Patient Clinical Features: A Retrospective Study

OBJECTIVES

To evaluate the role of clinical scores assessing the risk of disease severity in patients with clinical suspicion of obstructive sleep apnea syndrome (OSA). The hypothesis was tested by applying artificial intelligence (AI) to demonstrate its effectiveness in distinguishing between mild-moderate OSA and severe OSA risk.

METHODS

A support vector machine model (SVM) was developed from the samples included in the analysis (N = 498), and they were split into 75% for training (N = 373) with the remaining for testing (N = 125). Two diagnostic thresholds were selected for OSA severity: mild to moderate (apnea-hypopnea index (AHI) ≥ 5 events/h and AHI < 30 events/h) and severe (AHI ≥ 30 events/h). The algorithms were trained and tested to predict OSA patient severity.

RESULTS

The sensitivity and specificity for the SVM model were 0.93 and 0.80 with an accuracy of 0.86; instead, the logistic regression full mode reported a value of 0.74 and 0.63, respectively, with an accuracy of 0.68. After backward stepwise elimination for features selection, the reduced logistic regression model demonstrated a sensitivity and specificity of 0.79 and 0.56, respectively, and an accuracy of 0.67.

CONCLUSION

Artificial intelligence could be applied to patients with symptoms related to OSA to identify individuals with a severe OSA risk with clinical-based algorithms in the OSA framework.

Upper airway modifications after weight loss: a systematic review

OBJECTIVE

Weight loss is one of the most often prescribed treatments to reduce the level of sleep apnea severity; however, objective assessment of airway alterations after loss of weight has only been studied in the last decades. This study aimed at evaluating alterations after weight loss reported in the literature.

METHODS

A literature review was performed in the medical databases: PubMed, Web of Science, Scopus and Embase. A total of 681 articles were found in the databases and after evaluation only 10 studies were selected for data extraction.

RESULTS

Most studies observed an increase of the area in the retropalatal region; some indicating that this increase occurred mostly in the lateral pharyngeal region. Studies with volumetric reconstruction showed a significant reduction in parapharyngeal fat deposits, lateral wall and tongue fat, and volumetric reduction in all soft tissues of the pharynx, pterygoid and genioglossus muscles. Studies evaluating craniofacial bone structures showed a reduction in the airway height by bringing the hyoid closer to the posterior nasal spine and a reduction in the distance from the hyoid to the chin.

CONCLUSION

There is a limited number of studies with a good level of scientific evidence evaluating changes in the upper airways after weight loss and how these changes impact obstructive sleep apnea. The studies included in this review indicate that weight loss increases the airways space by reducing the volume of the parapharyngeal structures, particularly at the retropalatal site, where there is an apparent gain in the lateral area of the airway and hyoid relocation.

Classification of facial phenotypes in Asian patients with obstructive sleep apnea

BACKGROUD

The facial phenotypes of Asian obstructive sleep apnea (OSA) patients remain unclear.

OBJECTIVES

(1) To describe the facial features of OSA patients. (2) To develop a model based on facial contour indicators to predict OSA. (3) To classify the facial phenotypes of Asian OSA patients.

MATERIALS AND METHODS

110 patients with OSA (apnea-hypopnea index [AHI] ≥ 10/h) and 50 controls (AHI< 10/h) were selected to measure facial contour indicators. Indicators were compared between OSA patients and the control group. We used multivariable linear regression analysis to predict OSA severity and K-means cluster analysis to classify OSA patients into different phenotypes.

RESULTS

We built a model to predict OSA which explained 49.1% of its variance and classified OSA patients into four categories. Cluster 1 (Skeletal type) had the narrowest facial width indicators with narrowing of the retroglossal airway. Cluster 2 (Obese type) had the widest face, and narrowest hard palate, retropalatal, and hypopharyngeal airways. Cluster 3 (Nose type) had the narrowest nasal cavity. Cluster 4 (Long type) had the longest airway length.

CONCLUSIONS AND SIGNIFICANCE

Patients with OSA were classified into four categories, each of which identified different anatomic risk factors that can be used to select the treatment.

Dose-response relationship between weight loss and improvements in obstructive sleep apnea severity after a diet/lifestyle interventions: secondary analyses of the "MIMOSA" randomized clinical trial

STUDY OBJECTIVES

Lifestyle-induced weight loss is a complementary therapeutic approach for obstructive sleep apnea (OSA). We aimed at identifying the dose-response relationship between weight loss and OSA severity improvement.

METHODS

This is a secondary analysis of a 6-month clinical trial in 180 adult, overweight/obese moderate-to-severe OSA patients. Participants were randomized to a standard care, a Mediterranean diet, or a Mediterranean lifestyle arm. All patients were prescribed with continuous positive airway pressure (CPAP), while intervention arms additionally participated in a weight-loss dietary/lifestyle intervention. Based on percent change in weight at 6 months, participants were categorized into a weight-stable/gain (WS/GG) group or 3 weight-loss groups (WLG): < 5%WLG, 5%-10%WLG, and ≥ 10%WLG. Polysomnographic data and OSA symptoms were evaluated preintervention and postintervention.

RESULTS

Respiratory events and oximetry indices improved only in patients who lost weight and improvements were proportional to the degree of weight loss. Median percent change in apnea-hypopnea index (AHI) was -11.7%, - 37.9%, and - 49.3% in the < 5%WLG, 5%-10%WLG, and ≥ 10%WLG, respectively (P < .001). Compared to the WS/GG, the age-, sex-, baseline-, and CPAP use-adjusted relative risk (95% confidence interval) of severe OSA (AHI ≥ 30 events/h) was 0.45 (0.23-0.87) in the 5%-10%WLG and 0.32 (0.17-0.64) in the ≥ 10%WLG; the risk was also lower in the ≥ 10%WLG vs the < 5%WLG (0.42 [0.22-0.82]). Insomnia and daytime sleepiness also improved more in participants exhibiting ≥ 5% weight loss.

CONCLUSIONS

Even a < 5% weight loss can reduce respiratory events, but a ≥ 5% and ideally ≥ 10% weight loss is necessary for reducing the prevalence of severe OSA.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Mediterranean Diet/Lifestyle Intervention in Obstructive Sleep Apnea; URL: https://clinicaltrials.gov/ct2/show/NCT02515357; Identifier: NCT02515357.

CITATION

Georgoulis M, Yiannakouris N, Kechribari I, et al. Dose-response relationship between weight loss and improvements in obstructive sleep apnea severity after a diet/lifestyle intervention: secondary analyses of the "MIMOSA" randomized clinical trial. J Clin Sleep Med. 2022;18(5):1251-1261.