Duration of Sleep Apnea Linked to Increased Mortality

Sleep apnea and mortality

Obstructive sleep apnea is associated with increased cardiovascular morbidity and mortality. This study reviewed the effects of oral appliance therapy on a broad spectrum of cardiovascular outcomes. The literature search was performed up to December 2016. The resulting data showed significant reductions in daytime systolic and diastolic blood pressure compared to baseline with no significant reductions in heart rate. The study identified both continuous positive airway pressure (CPAP) and oral airway treatment (OAT). may lead to a reduction in long-term cardiovascular morbidity and mortality in obstructive sleep apnea (OSA) patients. The study is necessary to better address their question (de Vries et al, 2017).

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Obstructive sleep apnea (OSA) is a chronic disorder of the upper respiratory system characterized by repetitive collapse of the upper airway during sleep. This results in hypoxemia, increased sympathetic overdrive, increased blood pressure and increased carbon dioxide levels in the blood; resulting hypoxia is linked to a wide range of problems stemming from oxidative stress and inflammation and is associated with multiple cardiovascular morbidities, as well as coronary artery-related and all-cause mortality.

Obstructive sleep apnea is closely related to metabolic syndrome which includes obesity, hyperlipidemia, hypertension, and diabetes, the nature of these and obstructive sleep apnea may be bidirectional. The estimated prevalence of obstructive sleep apnea in the adult population is high, although estimates vary widely according to the samples and diagnostic threshold selected. Continuous positive airway pressure is considered the gold standard treatment of choice for obstructive sleep apnea.

The study showed no significant differences between adherence and non-adherent women with respect to age or to the severity of the obstructive sleep apnea indices. Significantly more women who were non-compliant were married with more adherence seen with women who were not. Possibly this was due to the CPAP machine bothering their partners sleep when it was in use.

Women who had moderate to severe obstructive sleep apnea may be identified first by complaints related to feeling tired in the morning, followed by perceived poor sleep quality, sleepiness during the day and trouble concentrating. These are the women more apt to be compliant in the CPAP use. There has been a challenge to encourage CPAP treatment adherence among women with fewer sleep and daytime functioning symptoms. The study noted there has been some consistent progress in designing and evaluating techniques for improved technological aspects and behavioral and cognitive-behavioral interventions (Libman et al, 2017).

Overlap syndrome is the co-occurrence of COPD and obstructive sleep apnea. This statement summarized the existing literature, identifies knowledge gaps and provides guidance regarding future priorities in research for sleep-disordered breathing in patients with COPD and other lung diseases. COPD is a major source of morbidity, mortality and healthcare costs. It is increasing in epidemic proportions because of the aging population, indoor and outdoor air pollution, historically smoking tend and other factors.

Efforts to slow the progression of COPD have failed in the majority of patients and research seeks to identify a new therapeutic approach to improve COPD, obstructive sleep apnea has a high prevalence and is associated with particularly poor outcomes, including high mortality. COPD is associated with abnormalities in respiratory mechanics and gas exchange. As a result, sleep is not a period of rest for the respiratory system but a physiological challenge for patients with impaired pulmonary mechanics.

Patients with overlap syndrome have been long recognized as having a unique and severe phenotype. Many patients with COPD are given supplemental oxygen on a long-term basis because of demonstrable abnormal gas exchange or for comfort. Supplemental oxygen may mask hypopnea during overnight testing by blunting oxygen desaturation due to hypoventilation.

Sleep study features in COPD are a consequence of sleep-induced respiratory loads. Patients with COPD may respond to increased respiratory loads with marked sleep disturbances or, alternatively, they may have minimal sleep disturbance but a highly abnormal breathing pattern with or without severe alterations in gas exchange. The study strongly advocates for further research into sleep-disordered breathing in patients with COPD to understand better the spectrum of disease, optimize the definitions the optimal mode of therapy (Malhotra et al, 2018).

Inadequate sleep whether caused by reduced sleep duration or obstructive an recurrent circadian disruption induced by might shift work adversely affect cardiovascular regulation and are associated with an increased risk of incident cardiovascular disease and death. Thirty percent of employed adults in the US and 44% of night shift workers reported sleeping on average six or fewer hours on work nights. Short sleep duration has been associated with increased risk for incident calcification of the coronary arteries, incident stroke, coronary heart disease, and death.

The prevalence of obstructive sleep apnea has risen over the past two decades in the US to an estimated 34% in males and 17% in females. In addition, obstructive sleep apnea has been associated with increased ventricular arrhythmias and all-cause mortality. While high-risk patients warrant further study, for now, it is uncertain if sleep and circadian disruption may further increase cardiovascular risk in a patient recovering from an acute coronary syndrome event.

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Overall, the median age of the study was 64 with 74.5% male. Mean report sleep duration as 7.4 hours with 9.7% of patients reporting they slept fewer than six hours daily. In the global, prospective study obstructive sleep apnea, short sleep duration, and overnight shift work were each independently associated with increased risk of a myocardial event. Furthermore, the presence of multiple sleep-related risk factors led to an additive increase in cardiovascular risk. The study also found more than one in three adults in the study screened positive for obstructive sleep apnea. Surveys of approximately 5000 police and 7000 firefighters showed more than 80% were identified at risk for obstructive sleep apnea but were untreated (Barger et al. (2017).

Chronic obstructive pulmonary disease (COPD) is a common, preventable and treatable disease that is characterized by persistent respiratory symptoms and largely irreversible airflow obstruction. COPD is a major global epidemic that occurs in greater than 10% of adults over 40 years of age, account for greater than 5% of physician office visits and 13% of all hospitalizations and has become the third leading cause of death in the US.

Obstructive sleep apnea is characterized by periods of partial or total intermittent collapse of the upper airway, resulting in nocturnal hypoxemia and arousal from sleep. In the US data collected from 2007 to 2010 showed an increasing trend with 26% of adults’ estimated to have mild to severe obstructive sleep apnea and even higher rates have been reported in some European countries.

Studying COPD-obstructive sleep apnea syndrome is relevant as hypoxemia is more profound in patients with the syndrome than either disorder alone. Furthermore, mortality and morbidity are increased if obstructive sleep apnea remains untreated. Many scales have been devised to determine the amount of sleep disruption the patient is experiencing. The Epworth Sleepiness Scale assesses daytime sleepiness.

The study was important because it demonstrated that commonly used obstructive sleep apnea predictors in the general population could differ in patients with advanced COPD. Also, it was found that the ESS questionnaire was not associated with obstructive sleep apnea. It doesn’t properly capture the degree of sleepiness in these individuals because obstructive sleep apnea symptoms present differently than those without COPD.

Neck circumference was not a factor with this study as the mean circumference was 40.7 cm for males and 35.1cm for females while 43.2cm and 40.6cm respectively are considered predictive of obstructive sleep apnea. This study found that patients with moderate to severe COPD have obstructive sleep apnea predictors that differ from those typically recognized in the general population. These findings are important in designing strategies to screen for important co-morbid conditions found on these patients. The researchers propose that specific tools are necessary to evaluate obstructive sleep apnea risk in this population and while they piloted a simple COPD sleep-screening questionnaire it needs further use to work out any shortcomings (Soler et al, 2017).

Works Cited
Barger, L.K. et al. (2017). Short sleep duration, obstructive sleep apnea, shift work and the risk of adverse cardiovascular events in patients after an acute coronary syndrome. Journal of American Heart Association, 6(10).

deVries et al. (2017). Cardiovascular effects of oral appliance therapy in obstructive sleep apnea: A systematic review and meta-analysis. Sleep Medicine Reviews. Elsevier.

Libman, E. et al. (2017). CPAP treatment adherence in women with obstructive sleep apnea. Sleep Disorders. Hindawi.

Malhotra, A. et al. (2018). Research priorities in pathophysiology for sleep-disordered breathing in patients with COPD. American Thoracic Society Documents. American Journal of Respiratory Critical Care Medicine,197(3).

Soler, X et al. (2017). Age, gender, neck circumference and Epworth sleepiness scale do not predict obstructive sleep apnea in moderate to severe COPD: The challenge to predict obstructive sleep apnea in advanced COPD. PLoS ONE, 12(5).

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