Arterial bicarbonate is associated with hypoxic burden and uncontrolled hypertension in obstructive sleep apnea - The ESADA cohort

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.

Adaptive responses to chronic intermittent hypoxia: contributions from the European Sleep Apnoea Database (ESADA) Cohort

Obstructive sleep apnoea (OSA) is a common disease in the general population, and is associated with increased cardiovascular risk and several comorbidities. Obesity favours upper airway collapsibility, but other pathophysiological traits have been identified, i.e. upper airway muscle activity, modulation of the respiratory drive, and the arousal threshold. OSA causes chronic intermittent hypoxia, inflammatory activation and autonomic imbalance with diurnal and nocturnal sympathetic hyperactivity. Disentangling so many components to investigate the pathogenesis of OSA's consequences is very hard clinically. However, albeit imperfect, clinical medicine constitutes a major source of inspiration for basic research, and a mutual exchange of information is essential between clinicians and physiologists to improve our understanding of disease states. OSA is no exception, and this narrative review will summarize the results of clinical studies performed over the years by the European Sleep Apnoea Database (ESADA) Study Group, to explore the variables linked to markers of intermittent hypoxia as opposed to the traditional assessment of OSA severity based on the frequency of respiratory events during sleep (the Apnoea Hypopnoea Index). The results of the clinical studies indicate that intermittent hypoxia variables are associated with several comorbidities, although evidence of a cause-effect relationship is still missing in many cases. It is also possible that adaptive rather than maladaptive responses could be evoked by intermittent hypoxia. The intensity, duration and frequency of intermittent hypoxia episodes causing adaptive rather than maladaptive responses, and their clinical implications, deserve further investigation.

Perspective: Systematic review and meta-analysis in obstructive sleep apnea - What is lacking?

Obstructive sleep apnea (OSA) affects nearly one billion of the global adult population. It is associated with substantial burden in terms of quality of life, cognitive function, and cardiovascular health. Positive airway pressure (PAP) therapy, commonly considered the first-line treatment, is limited by low compliance and lacking efficacy on long-term cardiovascular outcomes. A substantial body of research has been produced investigating (novel) non-PAP treatments. With increased understanding of OSA pathogenesis, promising therapeutic approaches are emerging. There is an imperative need of high-quality synthesis of evidence; however, current systematic reviews and meta-analyses (SR/MA) on the topic demonstrate important methodological limitations and are seldom based on research questions that fully reflect the complex intricacies of OSA management. Here, we discuss the current challenges in management of OSA, the need of treatable traits based OSA treatment, the methodological limitations of existing SR/MA in the field, potential remedies, as well as future perspectives.

Sleep and Breathing Conference highlights 2023: a summary by ERS Assembly 4

This paper presents some of the highlights of the Sleep and Breathing Conference 2023 https://bit.ly/46MxJml.

Effects of sex, age, and body mass index on serum bicarbonate

Rationale

Obesity hypoventilation syndrome (OHS) is often underdiagnosed, with significant morbidity and mortality. Bicarbonate, as a surrogate of arterial carbon dioxide, has been proposed as a screening tool for OHS. Understanding the predictors of serum bicarbonate could provide insights into risk factors for OHS. We hypothesized that the bicarbonate levels would increase with an increase in body mass index (BMI), since the prevalence of OHS increases with obesity.

Methods

We used the TriNetX Research Network, an electronic health record database with de-identified clinical data from participating healthcare organizations across the United States, to identify 93,320 adults without pulmonary or advanced renal diseases who had serum bicarbonate and BMI measurements within 6 months of each other between 2017 and 2022. We used linear regression analysis to examine the associations between bicarbonate and BMI, age, and their interactions for the entire cohort and stratified by sex. We also applied a non-linear machine learning algorithm (XGBoost) to examine the relative importance of age, BMI, sex, race/ethnicity, and obstructive sleep apnea (OSA) status on bicarbonate.

Results

This cohort population was 56% women and 72% white and 80% non-Hispanic individuals, with an average (SD) age of 49.4 (17.9) years and a BMI of 29.1 (6.1) kg/m2. The mean bicarbonate was 24.8 (2.8) mmol/L, with higher levels in men (mean 25.2 mmol/L) than in women (mean 24.4 mmol/L). We found a small negative association between bicarbonate and BMI, with an expected change of -0.03 mmol/L in bicarbonate for each 1 kg/m2 increase in BMI (p < 0.001), in the entire cohort and both sexes. We found sex differences in the bicarbonate trajectory with age, with women exhibiting lower bicarbonate values than men until age 50, after which the bicarbonate levels were modestly higher. The non-linear machine learning algorithm similarly revealed that age and sex played larger roles in determining bicarbonate levels than the BMI or OSA status.

Conclusion

Contrary to our hypothesis, BMI is not associated with elevated bicarbonate levels, and age modifies the impact of sex on bicarbonate.