Clinical presentation and comorbidities of obstructive sleep apnea-COPD overlap syndrome

2-Methoxyestradiol attenuates lung injury induced by chronic intermittent hypoxia via inhibiting the HIF1-α/SLC7A11 pathway

Ferroptosis is a novel type of programmed cell death associated with lung injury induced by chronic intermittent hypoxia (CIH). 2-Methoxyestradiol (2-ME2), as an inhibitor of Hypoxia-inducible factor 1 alpha (HIF-1α), affects HIF-1α-related biological processes. This study aimed to explore the role and mechanism of 2-ME2 on CIH-induced lung injury. CIH-associated lung injury was verified in SD rats. 2-ME2 was administered intraperitoneally at a dosage of 20 mg/kg to verify its treatment efficacy. CIH treated Human bronchoalveolar epithelial cells (BEAS-2B) were used to explore the mechanism of 2-ME2. HIF-1α knockdown cell lines and SLC7A11-overexpressing cell lines were established to explore the role of HIF-1α/SLC7A11 pathway in CIH-induced ferroptosis. The ChIP-qPCR was employed to determine the presence of binding sites between HIF-1α and the SLC7A11 promoter region. In vivo experiments demonstrated that, in comparison with the control group, there was an increase in lung injury scores and collagen ratio in the lung tissue of rats belonging to the CIH group, along with an upregulation of HIF-1α expression and alterations in the expression of ferroptosis-related genes (all p < 0.05). 2-ME2 mitigated the lung injury and ferroptosis induced by CIH in vivo. In vitro experiments revealed that, compared to BEAS-2B cells under normoxic conditions, HIF-1α expression increased significantly in BEAS-2B cells exposed to CIH. This was accompanied by alterations in the expression of ferroptosis-related genes (all p < 0.05) and an increase in both reactive oxygen species (ROS) and Fe2+ levels (both p < 0.05). HIF-1α knockdown, or SLC7A11 overexpression, reversed CIH-induced BEAS-2B cell ferroptosis. ChIP-qPCR confirmed the direct interaction between HIF-1α and SLC7A11 promoter region. The HIF-1α inhibitor, 2-ME2, effectively reverses CIH-induced lung tissue ferroptosis. The potential mechanism of 2-ME2 in inhibiting ferroptosis may involve suppressing the HIF-1α/SLC7A11 pathway.

Disruption of circadian rhythm as a potential pathogenesis of nocturia

Increasing evidence suggested the multifactorial nature of nocturia, but the true pathogenesis of this condition still remains to be elucidated. Contemporary clinical medications are mostly symptom based, aimed at either reducing nocturnal urine volume or targeting autonomic receptors within the bladder to facilitate urine storage. The day-night switch of the micturition pattern is controlled by circadian clocks located both in the central nervous system and in the peripheral organs. Arousal threshold and secretion of melatonin and vasopressin increase at night-time to achieve high-quality sleep and minimize nocturnal urine production. In response to the increased vasopressin, the kidney reduces the glomerular filtration rate and facilitates the reabsorption of water. Synchronously, in the bladder, circadian oscillation of crucial molecules occurs to reduce afferent sensory input and maintain sufficient bladder capacity during the night sleep period. Thus, nocturia might occur as a result of desynchronization in one or more of these circadian regulatory mechanisms. Disrupted rhythmicity of the central nervous system, kidney and bladder (known as the brain-kidney-bladder circadian axis) contributes to the pathogenesis of nocturia. Novel insights into the chronobiological nature of nocturia will be crucial to promote a revolutionary shift towards effective therapeutics targeting the realignment of the circadian rhythm.

Frequency of Stroke in Patients With Chronic Obstructive Pulmonary Disease: A Retrospective Study

Background Chronic obstructive pulmonary disease (COPD) is a progressive respiratory disorder associated with several comorbidities, including cardiovascular diseases. Objective This study aims to assess the frequency of stroke in patients presenting with COPD, explore associated risk factors, and examine the clinical outcomes of stroke in this population. Methods This retrospective cohort study was conducted using medical records from a tertiary care hospital. A total of 375 patients diagnosed with COPD were included in the study. Data were collected on demographic characteristics, COPD severity (as defined by the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria), comorbidities, stroke incidence (both ischemic and hemorrhagic), and related risk factors. Stroke severity and clinical outcomes, such as disability, hospitalization duration, and mortality, were also analyzed. Results The study found a significantly higher frequency of stroke in COPD patients compared to the general population. Stroke risk was particularly elevated in patients with advanced COPD, as well as those with comorbid hypertension, diabetes, and dyslipidemia. Both ischemic and hemorrhagic strokes were more common in COPD patients, with hypoxia and systemic inflammation being potential contributing factors. Patients who suffered a stroke had poorer clinical outcomes, with higher rates of disability, extended hospital stays, and increased mortality, compared to stroke patients without COPD. Conclusions COPD patients are at an increased risk of stroke, and this risk is further exacerbated by comorbid cardiovascular conditions and advanced stages of COPD.

Time course of hospitalizations in patients with heart failure and chronic obstructive pulmonary disease around sleep-disordered-breathing diagnosis

PURPOSE

In heart failure (HF) and chronic obstructive pulmonary disease (COPD) populations, sleep-disordered breathing (SDB) is associated with impaired health outcomes. We evaluated whether in patients with HF, concomitant HF and COPD or COPD, the number of hospitalizations would be reduced in the year after testing for SDB with and without treatment initiation compared to the year before.

METHODS

We performed a multicentre retrospective study of 390 consecutive sleep-clinic patients who had a primary diagnosis of chronic HF, HF and COPD or COPD and a secondary diagnosis of SDB. The date of SDB-testing was defined as the index date. Data on healthcare utilization was extracted for the 12-month period prior to and after this date.

RESULTS

The initiation of adaptive servoventilation (ASV) and non-invasive ventilation (NIV) treatment resulted in a statistically significant reduction in the number of hospitalisations. While continuous positive airway pressure (CPAP) treatment also demonstrated a reduction in hospitalisations, the observed effect did not reach the level of statistical significance. After accounting for demographics and comorbidities in multivariable regression analyses, only NIV was significantly associated with a reduction in hospitalizations, while CPAP or ASV were not. NIV appears to be underutilized in COPD.

CONCLUSIONS

Our data indicate, that patients with HF or COPD and concomitant SDB may benefit from the initiation of appropriate PAP-therapy. Whether treating SDB in HF- and COPD-patients influences healthcare utilization merits further investigation.

Respiratory Specialist Visits Before Admissions with COPD Exacerbation are Linked to Improved Management and Outcomes

Purpose

Exacerbations of COPD (ECOPD) significantly impact disease progression and mortality. Visiting a respiratory specialist (RS) in proximity to the exacerbation may lead to prompt treatment and improved outcomes. We aimed to evaluate the association between an RS visit 30-days before admission and exacerbation outcomes.

Patients and methods

The prospective study included subjects that were hospitalized with ECOPD between 2017 and 2019 in 13 medical centers. Pre-admission, in-hospital, and 30-day outcomes were assessed and compared between patients with and without a 30-day RS visit, using propensity score matching. A sub-group analysis was performed based on the reason for the RS visit (emergent vs regular follow-up).

Results

Three hundred and forty-four subjects were included, and 105 (31%) had pre-admission RS visit (RS group). Before matching, indicators of severe COPD were prevalent in the RS group, while after matching there were no differences. RS visits were associated with pre-hospital initiation of short acting bronchodilators (50% vs 36%), antibiotics (30% vs 17%), and systemic steroids (38% vs 22%). The RS group had longer duration between first symptoms to hospital arrival (median 5 vs 3 days, p < 0.01) and shorter hospital length-of-stay (median 4 vs 5 days, p = 0.04). In-hospital and 30-days outcomes were similar between the groups. However, a non-emergent pre-hospital RS visit was associated with improved in-hospital and 30-day outcomes.

Conclusion

Routine RS visits could lead to correct and early treatment for ECOPD with a potential for improved outcomes. These findings highlight the need for available specialists and higher awareness.

The Impact of Lung Function on Sleep Monitoring in Obstructive Sleep Apnea Associated with Obstructive Lung Diseases: Insights from a Clinical Study

Background/Objectives: Obstructive sleep apnea (OSA) and obstructive lung diseases (OLD) are common and interdependent respiratory disorders, where one condition may contribute to the development and worsening of the other (OLDOSA syndrome). The term OLDOSA syndrome includes two different conditions: Overlap syndrome (OVS: OSA + chronic obstructive pulmonary disease, COPD) and Alternative Overlap syndrome (aOVS: OSA + Asthma). Data on the interactions between lung function and respiratory monitoring during sleep in OLDOSA patients are few and controversial. Our study aims to evaluate the impact of lung function impairment on sleep breathing disorders, paying attention to the lack of literature about comparisons between OVS, aOVS, and the impact of small airways disease (SAD) in these patients. Methods: In total, 101 patients with a diagnosis of OSA and asthma or COPD underwent pulmonary function tests (PFTs) and nocturnal home sleep cardiorespiratory monitoring (HSCM). Exclusion criteria: Obesity hypoventilation syndrome (OHS) and other non-respiratory sleep disorders. Results: Sleep time with oxygen saturation below 90% (T90) was negatively correlated with forced expiratory volume in the first second, % of predicted (%FEV1), forced vital capacity, % of predicted (%FVC), forced expiratory flow at 25-75% of the pulmonary volume, % of predicted (%FEF25-75), and, after multivariable linear regression analysis, %FEF25-75 remained an independent factor for T90 with a negative correlation in mild and moderate OSA. Obstructive apnea index (oAI) and FEV1/FVC were negatively correlated in mild and moderate OSA. OVS presented with more severe OSA (higher AHI, oAI, and T90) and SAD (lower FEF25-75) compared to aOVS. Conclusions: This study highlights a possible interdependence between OLD and OSA; obstruction of the large and small airways at PFTs contributes to the worsening of these patients' nocturnal hypoxemia and obstructive events of the upper airway during sleep. Furthermore, this study shows that patients with OVS should be carefully monitored, as they present worse data at HSCM and have greater small airways involvement compared to aOVS.

Chronic Obstructive Pulmonary Disease and Obstructive Sleep Apnea Overlap Syndrome: An Update on the Epidemiology, Pathophysiology, and Management

This review provides an up-to-date summary of the prevalence, pathophysiology, diagnosis, and treatment of the chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) overlap syndrome (OVS). The presence of OVS is high in patients with COPD and in patients with OSA and is associated with profound nocturnal oxygen desaturation and systemic inflammation. There is a high prevalence of cardiovascular disease among patients with OVS and this likely contributes to increased mortality. Observational studies suggest that positive airway pressure therapy improves survival and reduces COPD exacerbations; however, randomized controlled trials will be required to confirm these findings.

Prognostic efficacy of non-invasive ventilation in patients with overlap syndrome: chronic obstructive pulmonary disease and obstructive sleep apnea

Background

Limited evidence exists regarding the effects of non-invasive ventilation (NIV) on the prognosis of patients with concomitant chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA), also known as overlap syndrome (OS). This study aimed to assess whether NIV alongside standard care could improve the prognosis of this cohort.

Methods

We retrospectively collected data from 229 patients with severe OS treated in Beijing Anzhen Hospital between January 1, 2016 and January 1, 2020, with follow-up until December 1, 2023. All patients were recommended usual care and NIV and were subsequently divided into non-NIV (usual care only) and NIV groups (usual care plus NIV) per their willingness and adherence to NIV. Endpoints included all-cause and acute exacerbation of COPD (AECOPD)-associated death and re-hospitalization. Multivariate analyses were used to determine the relationship of NIV with prognosis.

Results

The follow-up lasted for a median of 760 days (interquartile range, 245-1,374 days). Patients in the NIV group showed lower rates of all-cause (37.5% vs. 65.1%, P<0.001) and AECOPD-associated (31.7% vs. 58.7%, P<0.001) death compared with patients in the non-NIV group. Compared with usual care only, NIV treatment was associated with significant reduction in all-cause death [relative risks (RR) =0.459, 95% confidence interval (CI): 0.315-0.668, P<0.001], AECOPD-associated mortality (RR =0.424, 95% CI: 0.283-0.635, P<0.001), and re-hospitalization for all causes (RR =0.455, 95% CI: 0.342-0.605, P<0.001) and for AECOPD (RR =0.421, 95% CI: 0.308-0.575, P<0.001) in Cox hazards models, with significance persisting after multivariable adjustment.

Conclusions

NIV may improve outcomes and survival in patients with severe OS of comorbid COPD and OSA. Confirmatory studies are needed to prove benefits.

Prevalence of and factors associated with likely obstructive sleep apnea in individuals with airflow limitation

Introduction

Obstructive sleep apnea (OSA) is frequently associated with airflow limitation (AFL). However, information on the prevalence of and factors associated with likely OSA in individuals with AFL in Korea is limited.

Methods

Data from the 2019 Korea National Health and Nutrition Examination Survey (KNHANES) were used, and 3,280 individuals (2,826 individuals without AFL and 454 individuals with AFL) were included. AFL was defined as forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) < 0.7. A score ≥ 5 on the STOP-BANG questionnaire was used to identify individuals with likely OSA. The prevalence of likely OSA was compared between individuals with and without AFL. In addition, factors associated with likely OSA in individuals with AFL were evaluated using multivariable logistic regression analysis.

Results

Of 3,280 individuals, 13.8% had an AFL. The prevalence of likely OSA was significantly higher in individuals with AFL than in individuals without AFL (9.2% vs. 5.0%, p = 0.014). Among 454 individuals with AFL, obesity (adjusted odds ratio [aOR] = 14.78, 95% confidence interval [CI] = 4.20-52.02) was most strongly associated with likely OSA, followed by heavy alcohol consumption (aOR = 4.93, 95% CI = 1.91-12.70), hypertension (aOR = 4.92, 95% CI = 1.57-15.46), overweight (aOR = 4.71, 95% CI = 1.76-12.64), college graduate (aOR = 4.47, 95% CI = 1.10-18.22), and history of pulmonary tuberculosis (aOR = 3.40, 95% CI = 1.06-10.96).

Conclusion

In Korea, approximately 1 in 10 individuals with AFL had likely OSA. Overweight and obesity, heavy alcohol consumption, high educational level, hypertension, and history of pulmonary tuberculosis were associated with likely OSA in individuals with AFL.

Multidimensional phenotyping to distinguish among distinct obstructive sleep apnea, chronic obstructive pulmonary disease, and overlap syndrome phenotypes

OBJECTIVE/BACKGROUND

Chronic obstructive pulmonary disease (COPD), obstructive sleep apnea (OSA) and their comorbid association called Overlap Syndrome (OS) are frequent chronic diseases with high individual and societal burdens. Precise descriptions of the respective symptoms, comorbidities, and medications associated with these three conditions are lacking. We used a multidimensional phenotyping approach to identify relevant phenotypes characterizing these 3 disorders.

PATIENTS/METHODS

308 patients with OSA, COPD and OS were prospectively assessed using a combination of body shape measurements and multidimensional questionnaires evaluating sleep, fatigue, depression and respiratory symptoms. Comorbidities and medications were confirmed by physicians. Patients made home blood pressure self-measurements using a connected wearable device to identify undiagnosed or uncontrolled hypertension.

RESULTS

Three distinct relevant phenotypes were identified. OSA patients were round in shape with a balanced waist-to-hip ratio, frequent witnessed apneas, nocturia, daytime sleepiness, depression, and high diastolic blood pressure. COPD patients had a thinner body shape with a high waist-to-hip ratio, complained mainly of fatigue, and exhibited a higher resting heart rate. OS patients were round in shape with a balanced waist-to-hip ratio, reported little sleepiness and depression, but had impaired sleep and the highest rate of cardio-metabolic comorbidities. Diminished fitness-to-drive was most apparent in patients with OSA and OS. Home blood pressure measurements identified undiagnosed hypertension in 80 % of patients and in nearly 80 % of those with hypertension it was uncontrolled by their current medications.

CONCLUSIONS

Our systematic multidimensional phenotyping approach identified distinct body shapes, symptoms, and comorbidity profiles among patients with OSA, COPD, and OS.

Intermittent Versus Sustained Hypoxemia from Sleep-disordered Breathing: Outcomes in Patients with Chronic Lung Disease and High Altitude

In a variety of physiologic and pathologic states, people may experience both chronic sustained hypoxemia and intermittent hypoxemia ("combined" or "overlap" hypoxemia). In general, hypoxemia in such instances predicts a variety of maladaptive outcomes, including excess cardiovascular disease or mortality. However, hypoxemia may be one of the myriad phenotypic effects in such states, making it difficult to ascertain whether adverse outcomes are primarily driven by hypoxemia, and if so, whether these effects are due to intermittent versus sustained hypoxemia.

Targeting Hypercapnia in Chronic Lung Disease and Obesity Hypoventilation: Benefits and Challenges

Hypoventilation is a complication that is not uncommon in chronic obstructive pulmonary disease and calls for both medical treatment of the underlying disease and, frequently, noninvasive ventilation either during exacerbations requiring hospitalization or in a chronic state in the patient at home. Obesity hypoventilation syndrome by definition is associated with ventilatory failure and hypercapnia. It may or may not be accompanied by obstructive sleep apnea, which when detected becomes an additional target for positive airway pressure treatment. Intensive research has not completely resolved the best choice of treatment, and the simplest modality, continuous positive airway pressure, may still be entertained.

Sleep disordered breathing: OSA-COPD overlap

INTRODUCTION

Sleep has important effects on breathing and gas exchange that may have negative consequences in patients with chronic obstructive pulmonary disease (COPD). COPD and obstructive sleep apnea (OSA) are highly prevalent and may coexist, which is referred to as the overlap syndrome.

AREAS COVERED

The probability of OSA-COPD overlap represents the balance of protective and promoting factors such as hyperinflation and fluid retention; thus, different clinical COPD phenotypes influence the likelihood of comorbid OSA. The clinical presentation of OSA-COPD overlap is nonspecific, and the diagnosis requires clinical awareness to identify patients needing overnight studies. Both COPD and OSA are associated with a range of overlapping physiological and biological disturbances including hypoxia and inflammation that contribute to cardiovascular comorbidities. The management of OSA-COPD overlap patients differs from those with COPD alone and the survival of overlap patients treated with positive airway pressure (PAP) is superior to those untreated.

EXPERT OPINION

The recognition of OSA-COPD overlap has important clinical relevance because of its impact on outcomes and management. Management of the overlap should address both sleep quality and disordered gas exchange. PAP therapy has demonstrated reductions in COPD exacerbations, hospitalizations, healthcare costs and mortality in overlap patients.

Prevalence and Characteristics of Patients with Obstructive Sleep Apnea and Chronic Obstructive Pulmonary Disease: Overlap Syndrome

Overlap syndrome (OVS) is a distinct clinical entity that seems to result in potential cardiovascular consequences. We aimed to estimate the prevalence and risk factors for OVS in OSA patients and analyze clinical and PSG characteristics associated with OVS. In this cross-sectional study, 2616 patients evaluated for OSA underwent type-1 polysomnography (PSG). They were grouped as pure OSA (AHI > 15/h) and OVS patients. Demographics, PSG data, pulmonary function tests and arterial blood gases (ABGs) were compared between groups after adjustments for confounders. OSA was diagnosed in 2108 out of 2616 patients. Of those, 398 (19%) had OVS. Independent predictors of OVS were older age [OR: 5.386 (4.153-6.987)], current/former smoking [OR: 11.577 (7.232-18.532)], BMI [OR: 2.901 (2.082-4.044)] and ABG measurements [PaCO2 ≥ 45 OR: 4.648 (3.078-7.019), PO2 [OR: 0.934 (0.920-0.949)], HCO3- [OR: 1.196 (1.133-1.263), all p < 0.001]. OVS was also associated with prevalent hypertension [OR: 1.345 (1.030-1.758), p = 0.03] and cardiovascular disease [OR: 1.617 (1.229-2.126), p < 0.001], depressive symptoms [OR: 1.741 (1.230-2.465), p = 0.002] and nocturia [OR: 1.944 (1.378-2.742), p < 0.001], as well as with indices of OSA severity. Disturbances in sleep architecture were more prominent in OVS expressed by lower %N3 and REM% and higher arousal index. Our data suggest that OVS is prevalent among OSA patients, with distinct clinical and PSG characteristics. These characteristics could be utilized as predictive factors for early identification and further evaluation of these patients towards desirable patient-reported outcomes.

Exploring the impact of OSA on short-term survival in patients with AECOPD admitted to the ICU

BACKGROUND

Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is characterized by a sudden worsening of chronic obstructive pulmonary disease (COPD) symptoms, which significantly contributes to hospitalizations related to COPD symptoms. Previous research has mainly focused on the correlation between obstructive sleep apnea (OSA) and COPD. However, there were few studies that investigated the short-term mortality rate of AECOPD patients with or without OSA.

METHODS

Data for our research was taken from the Medical Information Mart for Intensive Care Database IV. A total of 1332 patients were included in the study based on well-defined criteria for selection and exclusion. By analyzing the characteristics of AECOPD patients, we compared those with and without OSA.

RESULTS

There were 1122 AECOPD patients without OSA, 210 patients with OSA. In comparison to those without OSA, patients with OSA exhibited lower 30-day and 90-day ICU mortality with unadjusted HR, as well as lower hospital mortality with unadjusted OR. However, after adjustments were made, there were no significant associations observed between OSA and short-term mortality, including 30-day ICU mortality, 90-day ICU mortality, ICU mortality, and hospital mortality in AECOPD patients. Subgroup analysis revealed that OSA may act as a risk factor for AECOPD patients with a BMI lower than 30 kg/m2.

CONCLUSIONS

There is no impact on short-term survival in AECOPD patients with OSA under intensive care unit (ICU) management and nursing.

Estimating the prevalence and clinical significance of chronic obstructive pulmonary disease-obstructive sleep apnea overlap in South Korea

INTRODUCTION

Concurrent obstructive sleep apnea (OSA) and chronic obstructive pulmonary disease (COPD) are referred to as COPD-OSA overlap. We investigated the prevalence and clinical significance of COPD-OSA overlap in the general population of South Korea.

METHODS

Data were obtained from the 2019 Korea National Health and Nutrition Examination Survey. Participants ≥40 years of age with complete STOP-Bang questionnaire and spirometry data were included. OSA was presumed in individuals with a STOP-Bang score of ≥3. COPD was determined using forced expiratory volume at 1 s/forced vital capacity <0.7. Participants were classified on the basis of the STOP-Bang score and spirometry findings. Clinical characteristics, comorbidities, and quality of life (using the EuroQoL 5-dimension instrument) were compared between the overlap group and COPD-alone or OSA-alone groups.

RESULTS

Among the 3157 participants, 6.9 % demonstrated COPD-OSA overlap. Individuals with OSA alone and COPD alone were 31.8 % and 5.2 %, respectively. The overlap group included more males, ever smokers, and frequent alcohol drinkers than the COPD- or OSA-alone groups. The overlap group had more diagnoses of hypertension, diabetes, and stroke than the COPD-alone group. The risk of anxiety/depression was approximately 2.5 times higher in the overlap group than in the COPD-alone group. COPD-OSA overlap was a significant risk factor for anxiety/depression after adjusting for age, sex, household income, and education levels.

CONCLUSION

COPD-OSA overlap is not rare within the general population of South Korea. Patients with overlap showed more comorbidities and higher levels of anxiety/depression than those in the COPD-alone group.

The Overlap Syndrome: A Combination of Chronic Obstructive Pulmonary Disease and Obstructive Sleep Apnea

Chronic obstructive pulmonary disease (COPD) is a severe lung disease that results in persistent and progressively worsening airflow obstruction due to abnormalities in the airway and alveoli. Obstructive sleep apnea (OSA) is a critical condition characterized by obstructive apneas, hypopneas, and respiratory effort-related arousals. These events occur due to the repetitive collapse of the upper airway during sleep, and it is essential to address this condition. These two conditions, when co-occur, are known as overlap syndrome (OS), which is associated with a higher likelihood of morbidity and mortality compared to either condition alone. Effective management of overlap syndrome is critical to maintain normal oxygen levels during sleep and reduce the incidence of hypoxemia and hypoventilation while improving sleep quality. Positive pressure ventilation is a standard technique used to effectively lower hospitalizations, emergency room visits, moderate and severe exacerbations, and related healthcare expenses in patients diagnosed with COPD and OSA. Despite the lack of literature on overlap syndrome, it is imperative to understand that this condition requires prompt and effective management to prevent further complications. Therefore, this review provides a detailed discussion highlighting the importance of proactive measures to manage overlap syndrome.

Co-existence of OSA and respiratory diseases and the influence of gender

INTRODUCTION

Sleep-disordered breathing (SDB), especially obstructive sleep apnea (OSA), is commonly associated with respiratory diseases, such as COPD, asthma and interstitial lung disease.

AREAS COVERED

This narrative review aims to comprehensively synthesize the existing information on SDB in respiratory diseases, investigate the role of gender in this association, and highlight the importance of OSA management in improving sleep, quality of life, and disease prognosis in these specific patient populations.

EXPERT OPINION

Research indicates a synergistic link between OSA and chronic respiratory diseases, which leads to greater morbidity and mortality compared to each disorder alone. Given the lack of an optimal OSA screening tool for these patients, a comprehensive patient approach and overnight diagnostic sleep study are imperative. Despite the limited evidence available, it seems that gender has an impact on the prevalence, severity, and susceptibility of this coexistence. Recognizing the role of gender in the coexistence of OSA and other respiratory diseases can enhance everyday medical practice and enable clinicians to adopt a more personalized approach toward optimal screening and diagnosis of these patients.

Mortality in obstructive sleep apnea syndrome (OSAS) and overlap syndrome (OS): The role of nocturnal hypoxemia and CPAP compliance

BACKGROUND

Obstructive sleep apnea syndrome (OSAS) and chronic obstructive pulmonary disease (COPD) are two chronic diseases that afflict many individuals worldwide with negative effects on health that may overlap in Overlap Syndrome (OS). The aim of our study was to investigate the differences in mortality between OSAS alone and OS and the risk factors involved.

METHODS

The study was conducted on patients with OSAS or OS diagnosis that completed 15-year follow-up between 2005 and 2023. Of these, the clinical, functional, sleep and survival data were registered and analysed. Risk factors were found by regression analysis.

RESULTS

501 patients (428 OSAS and 73 OS) were enrolled. Patients with OS had higher mortality than OSAS (p < 0,001). The morality risk factors for the overall population found were age >65 years (odds ratio (OR) = 10.69 (95%CI 3,85-29,69), p < 0,001) and low forced-expiratory volume in 1-s (FEV1) (OR = 10.18 (95%CI 2,32-44,68), p = 0,002). In patients with OSAS, age and nocturnal hypoxemia (NH) (OR = 2.41 (95%CI 1,07-5,41), p = 0,03) were risk factors, while adherence to nighttime positive airway pressure (PAP) reduced mortality (OR = 0,36 (95%CI 0,15-0,83), p = 0,017). Multivariate analysis confirmed age and FEV1 as risk factors in OS. Conversely, the risk factors for the overall population under 65 years were NH, which is confirmed in patients with OSAS alone (OR = 4,72 (95%CI 1,07-20,77), p = 0,04) in whom, on the other hand, PAP compliance reduced the mortality risk.

CONCLUSIONS

The study suggests that NH is a risk factor for all-cause mortality in sleep disorders by excluding the age; conversely, nighttime PAP improves the survival.

The Interplay between Obstructive Sleep Apnea, Chronic Obstructive Pulmonary Disease, and Congestive Heart Failure: Time to Collectively Refer to Them as Triple Overlap Syndrome?

BACKGROUND AND OBJECTIVES

Obstructive sleep apnea-hypopnea syndrome (OSAHS) and chronic obstructive pulmonary disease (COPD) are independently linked to an increase in cardiovascular disease (CVD). Only a few studies have been published linking the association between overlap syndrome and congestive heart failure (CHF). This review highlights the interplay between overlap syndrome (OSAHS-COPD) and CHF.

MATERIALS AND METHODS

We thoroughly reviewed published literature from 2005 to 2022 in PubMed, Google Scholar, and Cochrane databases to explore the link between overlap syndrome and cardiovascular outcomes, specifically congestive heart failure.

RESULTS

Research indicates that individuals with overlap syndrome are more likely to develop congestive heart failure than those with COPD or OSA alone. Congestive heart failure is a common comorbidity of overlap syndrome, and it has a two-way connection with sleep-related breathing disorders, which tend to occur together more frequently than expected by chance.

CONCLUSIONS

CHF seems to have a strong relationship with OS. Further research is required to understand the relationship between OS and CHF.

Comorbid Cognitive Impairment in Chronic Obstructive Pulmonary Disease (COPD): Current Understanding, Risk Factors, Implications for Clinical Practice, and Suggested Interventions

Cognitive impairment is a common comorbidity in patients with COPD, significantly impacting health and clinical outcomes. Yet it remains under investigated and is largely overlooked. Although the exact cause of cognitive impairment in patients with COPD is still unclear, factors such as hypoxemia, vascular disease, smoking, exacerbation, and physical inactivity have been suggested. While international guidelines recommend identifying comorbidity in patients with COPD, such as cognitive impairment, cognitive assessment is not yet part of the routine assessment. Unidentified cognitive deficits in patients with COPD may have severe impacts on clinical management, resulting in an inability to maintain functional independence, poor self-management, and a greater dropout from pulmonary rehabilitation programs. There is a need to consider cognitive screening as a part of COPD assessment to promote early detection of cognitive impairment. Recognizing cognitive impairment early in the course of the illness allows the development of individualized interventions to meet patients' needs and improve clinical outcomes. Pulmonary rehabilitation should be tailored to cognitively impaired patients with COPD to maximize the benefits and minimize the incompletion rate.

Sleep apnea-COPD overlap syndrome is associated with larger left carotid atherosclerotic plaques

Background

Little is known about whether the overlap syndrome (OS) combining features of chronic obstructive pulmonary disease (COPD) and sleep apnea-hypopnea syndrome increases the risk of stroke associated with COPD itself.

Methods

We prospectively studied 74 COPD patients and 32 subjects without lung disease. Spirometry and cardiorespiratory polygraphy were used to assess the pulmonary function of the study population and ultrasound measurements of intima media thickness (IMT) as well as the volume of plaques in both carotid arteries were also evaluated.

Results

Polygraphic criteria of OS were met in 51% of COPD patients. We found that 79% of patients with OS and 50% of COPD patients without OS had atherosclerotic plaques in the left carotid artery (p = 0.0509). Interestingly, the mean volume of atherosclerotic plaques was significantly higher in the left carotid artery of COPD patients with OS (0.07 ± 0.02 ml) than in those without OS (0.04 ± 0.02 ml, p = 0.0305). However, regardless of the presence of OS, no significant differences were observed in both presence and volume of atherosclerotic plaques in the right carotid artery of COPD patients. Adjusted-multivariate linear regression revealed age, current smoking and the apnea/hypopnea index (OR = 4.54, p = 0.012) as independent predictors of left carotid atherosclerotic plaques in COPD patients.

Conclusions

This study suggests that the presence of OS in COPD patients is associated with larger left carotid atherosclerotic plaques, indicating that OS might be screened in all COPD patients to identify those with higher risk of stroke.

The Overlap Syndrome of Obstructive Sleep Apnea and Chronic Obstructive Pulmonary Disease: A Systematic Review

Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) are common diseases that strongly impact the quality and length of life. Their coexistence is determined by overlap syndrome (OS). This systematic review aims to define the significance of these comorbidities according to the current state of knowledge. For this systematic review, we searched PubMed, Scopus, and Cochrane for studies published between 2018 and 26 October 2022, to find original, observational, human studies published in English, where the diagnosis of COPD was according to the Global Initiative for Obstructive Lung Disease guidelines and the diagnosis of OSA was based on polysomnography. The quality of studies was assessed using the Newcastle-Ottawa quality assessment tool for cohort and case-control studies, as well as its modification for cross-sectional studies. Of the 1548 records identified, 38 were eligible and included in this systematic review. The included studies covered a total population of 27,064 participants. This paper summarizes the most important, up-to-date information regarding OS, including the prevalence, meaning of age/gender/body mass index, polysomnography findings, pulmonary function, comorbidities, predicting OSA among COPD patients, and treatment of this syndrome.

Overlaps between obstructive sleep apnoea and other respiratory diseases, including COPD, asthma and interstitial lung disease

In the past, there was limited research relating to the role of sleep in respiratory diseases. Physicians treating these patients tended to focus mainly on the daily disabling symptoms, overlooking the possible significant role of coexisting sleep disorders such as obstructive sleep apnoea (OSA). Nowadays, OSA has been recognised as an important, highly prevalent comorbidity for respiratory diseases such as COPD, asthma and interstitial lung diseases (ILDs). Overlap syndrome refers to the coexistence of chronic respiratory disease and OSA in the same patient. Although, in the past, overlap syndromes have been poorly studied, recent data underline that they result in increased morbidity and mortality compared with either underlying disorder alone. OSA and respiratory disease may be of different severity, and this, along with the existence of various clinical phenotypes, points to the necessity of an individualised therapeutic plan. Early recognition and OSA management could offer key benefits, such as improved sleep, quality of life and disease outcomes.

Educational aims

Describe pathophysiological aspects of OSA in chronic respiratory diseases such as COPD, asthma and ILDs.Understand the bidirectional clinical importance when OSA coexists in chronic respiratory diseases.Review current knowledge of treatment strategies towards an individualised therapeutic plan resulting in patient-centric outcomes.

Hypoxia in Aging and Aging-Related Diseases: Mechanism and Therapeutic Strategies

As the global aging process continues to lengthen, aging-related diseases (e.g., chronic obstructive pulmonary disease (COPD), heart failure) continue to plague the elderly population. Aging is a complex biological process involving multiple tissues and organs and is involved in the development and progression of multiple aging-related diseases. At the same time, some of these aging-related diseases are often accompanied by hypoxia, chronic inflammation, oxidative stress, and the increased secretion of the senescence-associated secretory phenotype (SASP). Hypoxia seems to play an important role in the process of inflammation and aging, but is often neglected in advanced clinical research studies. Therefore, we have attempted to elucidate the role played by different degrees and types of hypoxia in aging and aging-related diseases and their possible pathways, and propose rational treatment options based on such mechanisms for reference.

Brazilian Thoracic Association Consensus on Sleep-disordered Breathing

Sleep is essential for the proper functioning of all individuals. Sleep-disordered breathing can occur at any age and is a common reason for medical visits. The objective of this consensus is to update knowledge about the main causes of sleep-disordered breathing in adult and pediatric populations, with an emphasis on obstructive sleep apnea. Obstructive sleep apnea is an extremely prevalent but often underdiagnosed disease. It is often accompanied by comorbidities, notably cardiovascular, metabolic, and neurocognitive disorders, which have a significant impact on quality of life and mortality rates. Therefore, to create this consensus, the Sleep-Disordered Breathing Department of the Brazilian Thoracic Association brought together 14 experts with recognized, proven experience in sleep-disordered breathing.

Impact of Positive Airway Pressure Therapy Adherence on Outcomes in Patients with Obstructive Sleep Apnea and Chronic Obstructive Pulmonary Disease

Rationale: The co-occurrence of obstructive sleep apnea and chronic obstructive pulmonary disease, termed overlap syndrome, has a poor prognosis. However, data on positive airway pressure (PAP) treatments and their impact on outcomes and costs are lacking. Objectives: This retrospective observational study investigated the effects of PAP on health outcomes, resource usage, and costs in patients with overlap syndrome. Methods: Deidentified adjudicated claims data for patients with overlap syndrome in the United States were linked to objectively measured PAP user data. Patients were considered adherent to PAP therapy if they met Centers for Medicare and Medicaid Services criteria for eight 90-day timeframes from device setup through 2-year follow-up. Propensity score matching was used to create comparable groups of adherent and nonadherent patients. Healthcare resource usage was based on the number of doctor visits, all-cause emergency room visits, all-cause hospitalizations, and PAP equipment and supplies, and proxy costs were obtained. Measurements and Main Results: A total of 6,810 patients were included (mean age, 60.8 yr; 56% female); 2,328 were nonadherent. Compared with the year before therapy, there were significant reductions in the number of emergency room visits, hospitalizations, and severe acute exacerbations during 2 years of PAP therapy in patients who were versus were not adherent (all P < 0.001). This improvement in health status was paralleled by a significant reduction in the associated healthcare costs. Conclusions: PAP usage by patients with overlap syndrome was associated with reduced all-cause hospitalizations and emergency room visits, severe acute exacerbations, and healthcare costs.

Cardiovascular outcomes in patients with COPD-OSA overlap syndrome: A systematic review and meta-analysis

Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnoea (OSA) are prevalent respiratory conditions that are independently associated with increased cardiovascular disease (CVD). It is not clear from current evidence whether COPD-OSA overlap syndrome confers an additive risk. This systematic review and meta-analysis investigated whether CVD was more prevalent in patients with overlap syndrome compared to either condition alone. We searched four electronic databases, screened 1826 records against the inclusion criteria. After screening, 18 retrospective, observational studies involving 4613 overlap patients, 16,046 OSA patients and 1679 COPD patients met the inclusion criteria. A random-effects meta-analysis of five studies (I2 = 61%) showed that overlap was associated with a significantly higher risk of hypertension compared to patients with COPD alone (OR = 1.68, 95%CI 1.21-2.35). Overlap was also associated with an increased risk of peripheral vascular disease compared to OSA alone (OR = 3.30 95%CI 2.66-4.10), with a subset of studies also suggesting an increased risk of ischaemic heart disease, heart failure, and cerebrovascular disease. However, it is worth noting that the findings are limited by the considerable heterogeneity of the studies, all of which were observational and retrospective in nature. This review highlights that patients with overlap syndrome have a high prevalence of CVD with some suggestion of an increased risk compared to patients with either condition alone.

OSA and Chronic Respiratory Disease: Mechanisms and Epidemiology

Obstructive sleep apnea (OSA) is a highly prevalent disorder that has profound implications on the outcomes of patients with chronic lung disease. The hallmark of OSA is a collapse of the oropharynx resulting in a transient reduction in airflow, large intrathoracic pressure swings, and intermittent hypoxia and hypercapnia. The subsequent cytokine-mediated inflammatory cascade, coupled with tractional lung injury, damages the lungs and may worsen several conditions, including chronic obstructive pulmonary disease, asthma, interstitial lung disease, and pulmonary hypertension. Further complicating this is the sleep fragmentation and deterioration of sleep quality that occurs because of OSA, which can compound the fatigue and physical exhaustion often experienced by patients due to their chronic lung disease. For patients with many pulmonary disorders, the available evidence suggests that the prompt recognition and treatment of sleep-disordered breathing improves their quality of life and may also alter the course of their illness. However, more robust studies are needed to truly understand this relationship and the impacts of confounding comorbidities such as obesity and gastroesophageal reflux disease. Clinicians taking care of patients with chronic pulmonary disease should screen and treat patients for OSA, given the complex bidirectional relationship OSA has with chronic lung disease.

Sleep-Related Breathing Complaints in Chronic Obstructive Pulmonary Disease

This review presents the normal physiologic changes in ventilation during sleep and how they can be detrimental to chronic obstructive pulmonary disease (COPD). Sleep-related breathing disorders (SRBDs) in COPD lead to higher morbidity and mortality if left unrecognized and untreated. The diagnosis of SRBDs requires a high index of suspicion, as symptoms may overlap with other sleep disorders. Mortality risk is improved when patients with COPD with OSA (overlap syndrome) are treated with positive airway pressure and when long-term nocturnal noninvasive ventilation is started on chronic stable hypercapnic COPD. Treatment of isolated nocturnal oxygen desaturation has not been associated with improved survival.

Clinical Factors Predictive of COPD Diagnosis in a Community Hospital

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is an irreversible obstructive airway disease. Diagnosis can be made using a spirometry which may not be available in resource-limited setting or developing countries. AIM: This study aimed to evaluate if clinical factors can be predictive of COPD diagnosis. MATERIALS AND METHODS: This study was a retrospective cohort study conducted at community hospital. The inclusion criteria were adult patients who had clinical symptoms suggestive of COPD and had performed adequate pulmonary function tests. Patients were categorized into two groups by diagnosis of COPD. Clinical predictors of being COPD were executed by multivariate logistic regression analysis. RESULTS: There were 200 patients who met the study criteria. Of those, 136 patients (68.00%) had compatible pulmonary function test with COPD. There were eight factors in the final predictive model for being COPD (Table 1). Among these factors, three factors were independently associated with being COPD: Productive sputum, body mass index, and hyperinflation by chest X-ray. The hyperinflation by chest X-ray had highest adjusted odds ratio of 10.93 (95% CI 3.23, 36.96). CONCLUSIONS: Productive sputum, body mass index, and hyperinflation by chest X-ray were independent factors for COPD diagnosis. Physicians in resource-limited setting may use these clinical factors as diagnostic tool for COPD.

Obstructive Sleep Apnea in Patients with Chronic Obstructive Pulmonary Disease: Facts and Perspectives

The co-occurrence of obstructive sleep apnea (OSA) and chronic obstructive pulmonary disease (COPD) in the same patient, named the overlap syndrome (OS), was first described in 1985. Although the American Thoracic Society underlined the limited knowledge of OS, stated research priorities for this condition, and recommended a "screening" strategy to identify OSA in COPD patients with chronic stable hypercapnia, research studies on OS remain scarce. This review aims to summarize the current knowledge and perspectives related to OSA in COPD patients. OS prevalence is 1.0-3.6% in the general population, 3-66% in COPD patients, and 7-55% in OSA patients. OS patients may have worse sleep quality than those with OSA or COPD alone. Scoring hypopneas may be difficult in COPD patients; desaturation episodes may have origins in these patients, namely upper airway obstruction, hypoventilation during paradoxical sleep, ventilation/perfusion mismatches, and obesity. The apnea-hypopnea index is similar in OSA and OS patients. Desaturations may be greater and more prolonged in OS patients than in patients with COPD or OSA alone. Low body mass index, hyperinflation, and less collapsible airways reduce the risk of OSA in COPD patients. OSA is a risk factor for pulmonary hypertension in COPD patients. Whether OS increases mortality and morbidity risks compared to COPD or OSA alone remains to be confirmed. No guidelines currently recommend specific approaches to the treatment of OSA in patients with COPD.

Impact of Healthcare Non-Take-Up on Adherence to Long-Term Positive Airway Pressure Therapy

Background: The effectiveness of positive airway pressure therapies (PAP) is contingent on treatment adherence. We hypothesized that forgoing healthcare may be a determinant of adherence to PAP therapy.

Research Question: The objectives were: (i) to assess the impact of forgoing healthcare on adherence to PAP in patients with Chronic Respiratory Failure (CRF) and patients with Obstructive Sleep Apnea Syndrome (OSAS); (ii) to compare forgoing healthcare patterns in these two chronic conditions.

Study design and methods: Prospective cohort of patients with OSAS or CRF, treated with PAP therapies at home for at least 12 months. At inclusion, patients were asked to fill-in questionnaires investigating (i) healthcare forgone, (ii) deprivation (EPICES score), (iii) socio-professional and familial status. Characteristics at inclusion were extracted from medical records. PAP adherence was collected from the device's built-in time counters. Multivariable logistic regression models were used to assess the associations between healthcare forgone and the risk of being non-adherent to CPAP treatment.

Results: Among 298 patients included (294 analyzed); 33.7% reported forgoing healthcare. Deprivation (EPICES score > 30) was independently associated with the risk of non-adherence (OR = 3.57, 95%CI [1.12; 11.37]). Forgoing healthcare had an additional effect on the risk of non-adherence among deprived patients (OR = 7.74, 95%CI [2.59; 23.12]). OSAS patients mainly forwent healthcare for financial reasons (49% vs. 12.5% in CRF group), whereas CRF patients forwent healthcare due to lack of mobility (25%, vs. 5.9 % in OSAS group).

Interpretation: Forgoing healthcare contributes to the risk of PAP non-adherence particularly among deprived patients. Measures tailored to tackle forgoing healthcare may improve the overall quality of care in PAP therapies.

Clinical Trial Registration: The study protocol was registered in ClinicalTrials.gov, identifier: NCT03591250.

Symptomatic response to CPAP in obstructive sleep apnea versus COPD- obstructive sleep apnea overlap syndrome: Insights from a large national registry

Background

The symptomatic response to continuous positive airway pressure (CPAP) therapy in COPD-obstructive sleep apnea overlap syndrome (OVS) compared to OSA syndrome (OSA) alone has not been well studied so far. The aim of this study is to explore main differences in the clinical response to CPAP treatment in OVS compared to OSA alone.

Study design and methods

Using prospective data from the French National Sleep Apnea Registry, we conducted an observational study among 6320 patients with moderate-to-severe OSA, available spirometry, and at least one follow-up visit under CPAP therapy.

Results

CPAP efficacy measured on the residual apnea-hypopnea index and median adherence were similar between OVS and OSA patients. In both groups, the overall burden of symptoms related to sleep apnea improved with CPAP treatment. In a multivariable model adjusted for age, gender, body mass index, adherence to treatment and residual apnea-hypopnea index, OVS was associated with higher odds for persistent morning headaches (OR: 1.37 [95% CI; 1.04; 1.79]; P = 0.02), morning tiredness (OR: 1.33 [95% CI: 1.12; 1.59]; P<0.01), daytime sleepiness (OR; 1.24 [95% CI: 1.4; 1.46]: P<0.01) and exertional dyspnea (OR: 1.26 [95% CI: 1.00;1.58]; P = 0.04) when compared with OSA alone.

Interpretation

CPAP therapy was effective in normalizing the apnea-hypopnea index and significantly improved OSA-related symptoms, regardless of COPD status. CPAP should be offered to patients with OVS on a trial basis as a significant improvement in OSA-related symptoms can be expected, although the range of response may be less dramatic than in OSA alone.

CPAP Therapy Termination Rates by OSA Phenotype: A French Nationwide Database Analysis

The nationwide claims data lake for sleep apnoea (ALASKA)—real-life data for understanding and increasing obstructive sleep apnea (OSA) quality of care study—investigated long-term continuous positive airway pressure (CPAP) termination rates, focusing on the contribution of comorbidities. The French national health insurance reimbursement system data for new CPAP users aged ≥18 years were analyzed. Innovative algorithms were used to determine the presence of specific comorbidities (hypertension, diabetes and chronic obstructive pulmonary disease (COPD)). Therapy termination was defined as cessation of CPAP reimbursements. A total of 480,000 patients were included (mean age 59.3 ± 13.6 years, 65.4% male). An amount of 50.7, 24.4 and 4.3% of patients, respectively, had hypertension, diabetes and COPD. Overall CPAP termination rates after 1, 2 and 3 years were 23.1, 37.1 and 47.7%, respectively. On multivariable analysis, age categories, female sex (1.09 (1.08–1.10) and COPD (1.12 (1.10–1.13)) and diabetes (1.18 (1.16–1.19)) were significantly associated with higher CPAP termination risk; patients with hypertension were more likely to continue using CPAP (hazard ratio 0.96 (95% confidence interval 0.95–0.97)). Therapy termination rates were highest in younger or older patients with ≥1 comorbidity. Comorbidities have an important influence on long-term CPAP continuation in patients with OSA.

Nocturnal Hypoxemia and CT Determined Pulmonary Artery Enlargement in Smokers

Background: Pulmonary artery enlargement (PAE) detected using chest computed tomography (CT) is associated with poor outcomes in chronic obstructive pulmonary disease (COPD). It is unknown whether nocturnal hypoxemia occurring in smokers, with or without COPD, obstructive sleep apnoea (OSA) or their overlap, may be associated with PAE assessed by chest CT. Methods: We analysed data from two prospective cohort studies that enrolled 284 smokers in lung cancer screening programs and completing baseline home sleep studies and chest CT scans. Main pulmonary artery diameter (PAD) and the ratio of the PAD to that of the aorta (PA:Ao ratio) were measured. PAE was defined as a PAD ≥ 29 mm in men and ≥27 mm in women or as a PA:Ao ratio > 0.9. We evaluated the association of PAE with baseline characteristics using multivariate logistic models. Results: PAE prevalence was 27% as defined by PAD measurements and 11.6% by the PA:Ao ratio. A body mass index ≥ 30 kg/m² (OR 2.01; 95%CI 1.06–3.78), lower % predicted of forced expiratory volume in one second (FEV₁) (OR 1.03; 95%CI 1.02–1.05) and higher % of sleep time with O₂ saturation < 90% (T90) (OR 1.02; 95%CI 1.00–1.03), were associated with PAE as determined by PAD. However, only T90 remained significantly associated with PAE as defined by the PA:Ao ratio (OR 1.02; 95%CI 1.01–1.03). In the subset group without OSA, only T90 remains associated with PAE, whether defined by PAD measurement (OR 1.02; 95%CI 1.01–1.03) or PA:Ao ratio (OR 1.04; 95%CI 1.01–1.07). Conclusions: In smokers with or without COPD, nocturnal hypoxemia was associated with PAE independently of OSA coexistence.