Association between respiratory events and nocturnal gastroesophageal reflux events in patients with coexisting obstructive sleep apnea and gastroesophageal reflux disease

A high arousal threshold is associated with nocturnal gastroesophageal reflux in obstructive sleep apnea

OBJECTIVE

Nocturnal gastroesophageal reflux (nGER) was reported to be associated with obstructive sleep apnea (OSA). However, pathophysiological traits in OSA patients with nGER were poorly understood, and arousal threshold (ArTH) might play an important role in this relationship. This study aimed to identify the clinical characteristics of patients with OSA comorbid with nGER, and investigate the association between ArTH and nGER in patients with OSA.

METHODS

482 adult patients with OSA diagnosed by polysomnography (PSG) at Peking University People's Hospital were recruited in this cross-sectional study. nGER presence was defined as typical nGER symptoms (heartburn or acid regurgitation occurring at night which affects sleep, with or without medication treatment) at least once a week in the past four weeks. A low ArTH was predicted based on the following PSG features: a total score of 2 or more, with one point assigned for each of the following criteria: apnea-hypopnea index (AHI) < 30/h, nadir oxygen saturation > 82.5 %, the proportion of hypopneas > 58.3 %, otherwise the ArTH was classified as high. Demographic and anthropometric characteristics, PSG parameters, and questionnaires related to clinical symptoms and comorbidities were obtained. The associations between nGER and clinical features were examined by multivariate logistic regressions.

RESULTS

The prevalence of typical nGER symptoms in patients with OSA was 17.8 %. High ArTH (P = 0.006), BMI ≥28 kg/m2 (P = 0.023), the Epworth Sleepiness Scale (ESS) Scores >16 (P = 0.006), and age over 60 years old (P = 0.002) were associated with a markedly increased risk of nGER in patients with OSA. Notably, in non-obese patients with OSA, a high ArTH not only significantly added to the presence of nGER (OR = 2.905, 95 % CI: 1.352-6.241, P < 0.01) after controlling for age, sex, ESS scores, comorbidities (including hypertension, diabetes mellitus, hyperlipidemia, coronary artery disease, and stroke) and total arousal index, but also associated with nGER symptom frequencies (OR = 2.856, 95 % CI = 1.118-7.294, P = 0.028) after adjusting for age, ESS scores, and medication use.

CONCLUSIONS

A high ArTH is independently associated with nGER in patients with OSA. For non-obese patients with OSA, a high ArTH is not only associated with the presence of nGER but also correlated with nGER symptom frequencies.

Association between obstructive sleep apnea and multiple adverse clinical outcomes: evidence from an umbrella review

Background and objective

In recent years, there has been a notable rise in awareness regarding obstructive sleep apnea (OSA), and a significant number of potential OSA cases have been identified. Numerous studies have established associations between OSA and various adverse clinical outcomes. This umbrella review aims to summarize and evaluate the available evidence on the relationship between OSA and multiple adverse clinical outcomes.

Methods

PubMed, Embase, and Web of Science databases were systematically searched from inception to September 2023. The AMSTAR and GRADE were used to evaluate the quality of meta-analysis literature and classify the quality of literature evidence. Furthermore, the size of the effect size of the association between OSA and adverse clinical outcomes were assessed by using either a random or fixed-effect model and 95% confidence interval (CI).

Results

A total of 27 meta-analyses were enrolled with 43 adverse clinical outcomes. The umbrella review primarily reported the associations between sleep apnea syndrome and thyroid cancer (HR = 2.32,95%CI:1.35-3.98), kidney cancer (RR = 1.81, 95% CI: 1.20-2.74), liver cancer (RR = 1.19, 95% CI: 1.10-1.29), GERD (Gastroesophageal reflux disease)(OR = 1.53, 95% CI: 1.23-1.91), Atrial fibrillation (AF) (OR = 2.54, 95% CI: 2.20-2.92), osteoporosis (OR = 2.03, 95% CI: 1.26-3.27), and diabetes (OR = 1.40, 95% CI: 1.32-1.48). Overall, the AMSTAR rating scale and GRADE quality assessment included in the meta-analysis were generally low.

Conclusion

Our study shows that OSA is significantly associated with a variety of adverse clinical outcomes, especially an increased risk of certain malignancies, and some adverse clinical outcomes are closely related to OSA severity.

Exploring the silent connection: unveiling the intricate relationship between gastroesophageal reflux disease and sleep apnea syndrome

BACKGROUND

Gastroesophageal reflux disease (GERD) and Sleep Apnea Syndrome (SAS) are two prevalent medical conditions that significantly affect health and quality of life. GERD involves stomach content reflux into the esophagus, while SAS causes recurrent upper airway obstruction during sleep. Despite recent studies hinting at a link, the precise relationship and causality between GERD and SAS remain unclear. Our research uses bidirectional Mendelian randomization to explore this intricate relationship. Additionally, given SAS's high prevalence in cardiovascular patients (40-80%, as highlighted by the American Heart Association), we also investigated its potential association with various cardiovascular diseases to gain new insights into prevention and treatment.

METHODS

This study employed genetic data from large-scale genome-wide association studies (GWAS) on GERD (129,080 cases, 473,524 controls) and SAS (25,008 cases, 391,473 controls) for two-sample Mendelian randomization (MR) analysis to estimate the causal effects of GERD on the risk of SAS. All SNPs were selected using a strict clump window (r2 = 0.001 and kb = 10,000). We initially applied the inverse variance weighted (IVW) method and measured horizontal pleiotropy using MR-Egger, weighted median, and weighted mode methods. I2 index and Cochran Q statistics were used for sensitivity analysis. Funnel plot symmetry of IVW MR estimates versus 1/standard error (1/SEIV) was examined to exclude SNPs potentially causing heterogeneity. Additionally, to exclude reverse causality, bidirectional MR was employed to investigate whether genetic susceptibility to SAS causally influenced the risk of GERD.

RESULTS

GERD was associated with an elevated risk of SAS, demonstrating an odds ratio (OR) of 1.750 (95% CI 1.590-1.930; P < 0.001). Conversely, there was no compelling evidence to indicate a causal link between SAS and the risk of developing GERD, with an OR of 1.000 (95% CI 0.989-1.011; P = 0.964). In addition to the primary findings, our study also revealed significant risks associated with SAS for several cardiovascular conditions, including coronary heart disease, atrial fibrillation, coronary artery disease, heart failure, intracerebral hemorrhage, and ischemic stroke.

CONCLUSION

We discovered compelling evidence indicating an elevated risk of SAS in individuals with GERD, but no significant evidence supporting an increased risk of GERD in those with SAS. Future investigations into SAS risk should take into account the potential therapeutic targeting of GERD. PPI and histamine antagonists can effectively reduce reflux and airway secretions, preventing airway damage and collapse. Furthermore, it is necessary to investigate the underlying mechanisms by which GERD affects SAS. For example, the inflammatory stimulation caused by gastric acid and pepsin in refluxed fluid, as well as the increased tension of bronchial smooth muscle caused by vagus nerve reflex. Thus, early preventive measures can be implemented for potential complications related to SAS.

Uncovering Diaphragm Cramp in SIDS and Other Sudden Unexpected Deaths

The diaphragm is the primary muscle of respiration. Here, we disclose a fascinating patient's perspective that led, by clinical reasoning alone, to a novel mechanism of spontaneous respiratory arrests termed diaphragm cramp-contracture (DCC). Although the 7-year-old boy survived its paroxysmal nocturnal "bearhug pain apnea" episodes, essentially by breathing out to breathe in, DCC could cause sudden unexpected deaths in children, especially infants. Diaphragm fatigue is central to the DCC hypothesis in SIDS. Most, if not all, SIDS risk factors contribute to it, such as male sex, young infancy, rebreathing, nicotine, overheating and viral infections. A workload surge by a roll to prone position or REM-sleep inactivation of airway dilator or respiratory accessory muscles can trigger pathological diaphragm excitation (e.g., spasms, flutter, cramp). Electromyography studies in preterm infants already show that diaphragm fatigue and sudden temporary failure by transient spasms induce apneas, hypopneas and forced expirations, all leading to hypoxemic episodes. By extension, prolonged spasm as a diaphragm cramp would induce sustained apnea with severe hypoxemia and cardiac arrest if not quickly aborted. This would cause a sudden, rapid, silent death consistent with SIDS. Moreover, a unique airway obstruction could develop where the hypercontracted diaphragm resists terminal inspiratory efforts by the accessory muscles. It would disappear postmortem. SIDS autopsy evidence consistent with DCC includes disrupted myofibers and contraction band necrosis as well as signs of agonal breathing from obstruction. Screening for diaphragm injury from hypoxemia, hyperthermia, viral myositis and excitation include serum CK-MM and skeletal troponin-I. Active excitation could be visualized on ultrasound or fluoroscopy and monitored by respiratory inductive plethysmography or electromyography.

Relationship between obstructive sleep apnoea syndrome and gastrointestinal diseases: a systematic review and Meta-analysis

Studies exploring the association between obstructive sleep apnoea syndrome (OSA) and gastrointestinal diseases (GID) are important for enhancing clinical outcomes. This study aimed to systematically assess the association between these two diseases. Adhering to PRISMA guidelines, a comprehensive literature search was conducted across databases including PubMed, Web of Science, Willey Library, Cochrane Library and Scopus. This search focused on English literature published up to January 2024. Literature screening, quality assessment (using the NOS scale) and data extraction were performed by two independent researchers. Statistical analyses were performed using the meta-package of the R.4.2.2 software. An initial screening of 2178 papers was conducted and 11 studies were included. Meta-analysis results showed a significant association between OSA and GID (p < 0.01). Subgroup analyses further indicated a stronger association between OSA and GID in Asian populations compared to Europe and the United States. In addition, both benign and malignant GID were significantly associated with OSA, with a pronounced association for malignant GID than for benign GID. The results of publication bias analysis revealed no significant bias (Begg's test p = 0.45, Egger's test p = 0.60). This study uncovers a notable association between OSA and GID, especially in Asian populations, suggesting that clinicians should consider the potential connection between these two diseases during diagnosis and treatment. However, due to the heterogeneity and limitations of the study, these conclusions need to be further validated through more comprehensive research.

Assessment and Management of Cough in Idiopathic Pulmonary Fibrosis: A Narrative Review

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and fatal disease with an unknown cause. It is characterized by symptoms such as cough and breathlessness, which significantly impact patients' quality of life. Cough, in particular, has emerged as a burdensome symptom for individuals with IPF. The etiology of cough in IPF patients is believed to be complex, involving factors related to the disease itself, such as increased sensitivity of cough nerves, lung structural changes, inflammation, and genetic factors, as well as comorbidities and medication effects. Unfortunately, effective treatment options for cough in IPF remain limited, often relying on empirical approaches based on studies involving chronic cough patients in general and the personal experience of physicians. Medications such as opioids and neuromodulators are commonly prescribed but have shown suboptimal efficacy, imposing significant physical, psychological, and economic burdens on patients. However, there is hope on the horizon, as specific purinergic P2 receptor ligand-gated ion channel (P2X3) inhibitors have demonstrated promising antitussive effects in ongoing clinical trials. This review aims to provide a comprehensive overview of the evaluation and management of cough in IPF patients, as well as highlight emerging pharmacological and non-pharmacological approaches that target the cough reflex and are currently being investigated in clinical settings.

Association between obstructive sleep apnea and gastroesophageal reflux disease: A systematic review and meta-analysis

BACKGROUND AND AIM

We aim to conduct a systematic review and determine the association between obstructive sleep apnea (OSA) and gastroesophageal reflux disease (GERD).

METHODS

Literature search for eligible studies was performed across major databases. The main endpoint was to assess the association between GERD and OSA. Subgroup analyses were performed to determine this strength of the association stratified by the diagnostic tools used for OSA (nocturnal polysomnogram or Berlin questionnaire) and GERD (validated reflux questionnaire or esophagogastroduodenoscopy). We also compared sleep efficiency, apnea hypopnea index, oxygen desaturation index, and Epworth Sleepiness Scale in OSA patients with or without GERD. Results were pooled together using Reviewer Manager 5.4.

RESULTS

Six studies involving 2950 patients with either GERD or OSA were included in the pooled analysis. Our findings suggest that there was a statistically significant unidirectional association between GERD and OSA (odds ratio [OR] = 1.53, P = 0.0001). Subgroup analyses redemonstrated an OSA-GERD association irrespective of the tools used for diagnosing either GERD or OSA (P = 0.24 and P = 0.82, respectively). Sensitivity analyses demonstrated the same association after controlling for gender (OR = 1.63), BMI (OR = 1.81), smoking (OR = 1.45), and alcohol consumption (OR = 1.79). In patients with OSA, there were no statistically significant differences between patients with or without GERD in terms of apnea hypopnea index (P = 0.30), sleep efficiency (P = 0.67), oxygen desaturation index (P = 0.39), and Epworth Sleepiness Scale (P = 0.07).

CONCLUSION

There exists an association between OSA and GERD that is independent of the modalities used for screening or diagnosing both disorders. However, the presence of GERD did not affect the severity of OSA.

Effect of positive airway pressure compliance on laryngopharyngeal reflux in obstructive sleep apnea patients

OBJECTIVES

To determine the effect of continuous positive airway pressure (CPAP) compliance on symptoms and signs of laryngopharyngeal reflux (LPR) in patients with obstructive sleep apnea (OSA).

RESULTS

Thirty patients were included. The participants were divided into good compliance (n = 21) and poor compliance (n = 9) groups. After 6-month CPAP treatment, the reflux symptom index score significantly decreased in both the good compliance group (20 (17,24) vs. 14 (10,18), p < 0.001) and the poor compliance group (21 (18,25) vs. 10 (5,16), p < 0.05). Reflux finding score was significantly reduced in both the good compliance group (8 (6,9) vs. 4 (3,5), p < 0.001) and the poor compliance group (6 (4,8) vs. 3 (2,4), p < 0.05). However, there were no statistically significant differences between the groups. CPAP treatment reduces the symptoms and signs of LPR. However, CPAP compliance does not correlate with improvement in LPR in patients with OSA.

Risk factors for Barrett's esophagus: Recent advances

Esophageal adenocarcinoma (EAC) is the most common malignant tumor of the esophagus in the West. During the past few decades, its morbidity has been increasing in China. Barrett's esophagus (BE) is defined as the replacement of normal squamous epithelium in the lower esophagus by metaplasia of columnar epithelium. BE is closely related to the occurrence of EAC. Knowledge regarding the risk factors for the occurrence and development of BE is of great significance for early screening and diagnosis of BE and prevention of EAC. In this paper, we review the clinical, demographics-related, lifestyle-related, and medications-related risk factors for BE to provide more valuable scientific evidence for the prevention and treatment of BE.

The uses of overnight pulse oximetry

Overnight pulse oximetry (OPO) has proven to be an effective and beneficial technique to determine the cardiorespiratory status of patients in both the inpatient and outpatient settings. It is a cheap, safe, reliable, simple, and accurate method of patient monitoring as compared to the expensive and labor-intensive method of multichannel polysomnography for detecting sleep-disordered breathing. It provides accurate information about patient's oxygenation status and also helps in monitoring the response to continuous positive airway pressure and in the surgical treatment of obstructive sleep apnea (OSA). Nocturnal hypoxemia portends a poor prognosis in patients of chronic obstructive pulmonary disease (COPD), interstitial lung disease (ILD), and neuromuscular diseases. OPO can help its early detection and management.

The relationship between obstructive sleep apnea hypopnea syndrome and gastroesophageal reflux disease: a meta-analysis

BACKGROUND

Obstructive sleep apnea hypopnea syndrome (OSAHS) means apnea and hypopnea caused by partial or complete obstruction of upper airway collapse during sleep. Gastroesophageal reflux disease (GERD) is believed to be associated with various manifestations in the otorhinolaryngology and has been found to be an additional risk factor for OSAHS.

AIM

A meta-analysis was performed to identify the association between obstructive sleep apnea hypopnea syndrome and gastroesophageal reflux disease.

METHODS

To identify eligible original articles, we searched a series of computerized databases, including Medline via PubMed, EMBASE, Web of Science, and CNKI with a systematic searching strategy. The characteristics of each article and pooled odds ratios (ORs) with corresponding confidence intervals (CIs) were calculated and subgroup analysis was performed to analyze the source of heterogeneity.

RESULTS

A total of 2699 patients from seven articles were included in the meta-analysis. We identified a significant relationship between obstructive sleep apnea syndrome and gastroesophageal reflux disease, with a pooled OR of 1.75 (95% CI 1.18-2.59, P < 0.05). The pooled data was calculated under the random-effects model as a significant moderate heterogeneity was found among the meta-analysis.

CONCLUSIONS

The meta-analysis showed that there was a significant correlation between obstructive sleep apnea hypopnea syndrome and gastroesophageal reflux disease.

The pathogenetic mechanisms of cough in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis is a peripheral subpleural interstitial lung disorder limited to the lung not involving the airways. It has a poor prognosis (survival less than 5 years) and commonly an interstitial pneumonia radiological pattern. Patients complain of a chronic dry cough in 80% of cases. A cough is often the first symptom of this rare disease, preceding dyspnea by years, and is associated with a poor prognosis, high dyspnea scores and low FVC percentages. The pathogenetic mechanisms leading to coughing in IPF are unclear. This review focuses on recent evidence of cough pathophysiology in this disease. Gastroesophageal reflux may promote coughing in IPF patients; bile salts and pepsin may be abundant in BAL of these patients, inducing overproduction of TGF-β by airway epithelial cells and mesenchymal transition with fibroblast recruitment/activation and extracellular matrix deposition. Patients have an enhanced cough reflex to capsaicin and substance P with respect to control subjects. Moreover, patients with the MUC5B polymorphism show more severe coughing as MUC5B encodes for the dominant mucin in the honeycomb cysts of IPF patients. Comorbidities, including asthma, gastroesophageal reflux, hypersensitivity pneumonitis, bronchiectasis, chronic obstructive pulmonary disease and emphysema, can induce coughing in IPF patients. There is no clear explanation of the causes of coughing in IPF. Further research into the pathophysiology of IPF and the pathogenetic mechanisms of coughing is necessary to improve survival and quality of life.

Association between bruxism and symptomatic gastroesophageal reflux disease: A case-control study

OBJECTIVES

To examine the relation between bruxism and gastroesophageal reflux disease (GERD) and the contribution of depression, anxiety and impaired sleep quality to that association.

METHODS

A three-centre case-control study was conducted consisting of 887 consecutive clinically-diagnosed bruxism patients aged 18-75 years and 887 matched controls. Diagnosis of GERD was based on the Montreal definition: moderate/severe symptoms ≥ one day/week or mild symptoms ≥ two days/week. Logistic regression was used to evaluate the association between bruxism and GERD. Mediation analyses were used to test whether the association between bruxism and GERD was mediated by depression, anxiety or impaired sleep quality.

RESULTS

Binary logistic regression identified that GERD was associated with bruxism (odds ratio, 6.87; 95% confidence interval (CI), 4.34-10.88). This association was stronger in females (odds ratio, 12.27; 95% CI, 5.81-25.91) than in males (odds ratio, 3.99; 95% CI, 2.17-7.32). Multinomial logistic regression identified that GERD was associated with all types of bruxism (sleep bruxism alone, odds ratio, 6.71, 95% CI, 4.22-10.68; awake bruxism alone, odds ratio, 13.06, 95% CI, 5.32-32.05; overlap of sleep bruxism and awake bruxism, odds ratio, 6.48, 95% CI, 3.05-13.77). Ordinal logistic regression identified that longer GERD duration (> 2 years vs ≤ 2 years) was associated with bruxism frequency (odds ratio, 1.50; 95% CI, 1.10-2.05). Mediation analyses found that the association between bruxism and GERD was partially-mediated through depression, anxiety and impaired sleep quality.

CONCLUSIONS

Clinically-diagnosed bruxism is associated with symptomatic GERD and is partially-mediated through depression, anxiety and impaired sleep quality.

CLINICAL SIGNIFICANCE

Because bruxism is strongly associated with symptomatic GERD and patients with frequent bruxism symptoms tend to suffer from GERD for extensive time-periods, dentists should consider evaluation of GERD status as an elemental part of the medical examination of bruxism, especially severe bruxism.

Gastroesophageal Reflux Disease

Gastroesophageal reflux (GER) is a normal physiologic process. It is important to distinguish GER from GER disease (GERD) since GER does not require treatment. Although a diagnosis of GERD can largely be based on history and physical alone, endoscopy and pH impedance studies can help make the diagnosis when there in atypical presentation. In children and adolescents, lifestyle changes and acid suppression are first-line treatments for GERD. In infants, acid suppression is not effective, but a trial of hydrolyzed formula can be considered, as milk protein sensitivity can be difficult to differentiate from GER symptoms.

Evaluation of pulse oximeter derived photoplethysmographic signals for obstructive sleep apnea diagnosis

High prevalence of obstructive sleep apnea (OSA) has increased the demands for more convenient and accessible diagnostic devices other than standard in-lab polysomnography (PSG). Despite the increasing utility of photoplethysmograph (PPG), it remains understudied in underserved populations. This study aimed to evaluate the reliability of a standard pulse oximeter system with an automated analysis based on the PPG signal for the diagnosis of OSA, as compared with PSG derived measures.Consecutive out-patients with suspect OSA completed a PPG monitoring simultaneous with an overnight in-lab standard PSG. Forty-nine OSA patients (38 males, age 43.5 ± 16.9 years, BMI 26.9 ± 0.5 kg/m) were included in this study. Automated analyses were based on PPG and oximetry signals only. The PPG calculated measures were compared with PSG derived measures for agreement tests.Respiratory events index derived from PPG significantly correlated with PSG-derived apnea-hypopnea index (r = 0.935, P < .001). The calculation of total sleep time and oxygen desaturation index from PPG and PSG also significantly correlated (r = 0.418, P = .003; r = 0.933, P < .001, respectively). Bland-Altman plots showed good agreement between the PPG and the PSG measures. The overall sensitivity and specificity of PPG are good, especially in moderate and severe OSA groups.The tested PPG approach yielded acceptable results compared to the gold standard PSG among moderate to severe OSA patients. A pulse oximeter system with PPG recording can be used for the diagnosis or screening of OSA in high risk population.