Mortality in Patients Treated with Continuous Positive Airway Pressure at the Population Level

Effect of CPAP Treatment on Cardiovascular Outcomes

INTRODUCTION

Randomized controlled trials (RCT) have not demonstrated a role for continuous positive airway pressure (CPAP) on the secondary prevention of major cardiovascular events in obstructive sleep apnea (OSA) patients. However, participants in RCTs are substantially different from real-world patients. Therefore, we aimed to assess the effect of CPAP treatment on major cardiovascular events in real-world OSA patients.

METHODS

Population-based longitudinal observational study including all OSA patients with an active CPAP prescription at the beginning of 2011 in Catalonia, Spain, that terminated CPAP treatment during 2011 and did not have CPAP prescriptions between 2012-2015; and propensity-score-matched OSA patients that continued CPAP treatment until the end of 2015 or death. Adjusted hazard ratios were used to assess the association between CPAP treatment and overall and cardiovascular mortality, cardiovascular hospitalizations, or major adverse cardiovascular events (MACEs).

RESULTS

3638 CPAP terminators and 10,914 propensity-score-matched continuators were included (median age 67 [57-77] years, 71.4% male). During a median follow-up of 47.9 months CPAP continuators showed a lower risk of cardiovascular death than terminators (hazard ratio [HR]: 0.61; 95% confidence interval [CI]: 0.50-0.75) after adjusting by age, sex and key comorbidities. Similar results were found for cardiovascular hospitalizations (HR: 0.87; 95% CI: 0.76-0.99) and MACEs (HR: 0.84; 95% CI: 0.75-0.95).

CONCLUSION

CPAP treatment continuation could be associated with a significantly lower risk of major cardiovascular events in real-world OSA patients. This result highlights the importance of including real-world patients in studies on OSA.

The Correlation of Computerized Scoring in Home Sleep Apnea Tests with Technician Visual Scoring for Assessing the Severity of Obstructive Sleep Apnea

Background: Obstructive sleep apnea (OSA) affects a significant proportion of the global population, with many having moderate or severe forms of the disease. Home Sleep Apnea Testing (HSAT) has become the most common method of diagnosing OSA, replacing in-lab polysomnography. Polysmith software Version 11 by Nihon Kohden allows for the automatic scoring of respiratory events. This study aimed to assess the validity of this technology. Study Objectives: The objective was to assess the accuracy of the Polysmith Software Automatic Scoring Algorithm of HSATs in comparison to that of sleep technicians. Methods: One hundred twenty HSATs were scored by both sleep technicians and Polysmith software. The measured values were the respiratory event index (REI), apneic events, and hypopneic events. Agreement between the two methods was reached by utilizing the Kruskal-Wallis test, Pearson correlation coefficient, and Bland-Altman plot, as well as sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Results: The correlation between the REI calculated by the software and technicians proved to be strong overall (r = 0.96, p < 0.0001). The mild OSA group had a moderate correlation (r = 0.45, p = 0.0129). The primary snoring, moderate OSA, and severe OSA groups showed stronger correlations (r = 0.69, p < 0.0001; r = 0.56, p = 0.012; r = 0.71, p < 0.0001). The analysis conducted across all groups demonstrated an average sensitivity of 81%, specificity of 94%, PPV of 82%, and NPV of 94%, with an overall accuracy of 81%. When combining the moderate and severe OSA groups into a single category, the sensitivity was 90%, specificity was 100%, PPV was 100%, and NPV was 91%. Conclusions: OSA can be reliably diagnosed from HSATs with the automated Polysmith software across all OSA disease severity groups, with higher levels of accuracy in moderate/severe OSA and lower levels of accuracy in mild OSA.

Relationship Between CPAP Termination and All-Cause Mortality: A French Nationwide Database Analysis

BACKGROUND

Randomized controlled trials have failed to demonstrate an effect of CPAP therapy on mortality. However, these studies have a number of important limitations, including low CPAP adherence, patient selection, and a small number of mortality events.

RESEARCH QUESTION

What are the effects of CPAP therapy termination in the first year on all-cause mortality in patients with OSA from the Nationwide Claims Data Lake for Sleep Apnea study?

STUDY DESIGN AND METHODS

Data from the Système National des Données de Santé (SNDS) database, the French national health insurance reimbursement system, for all new CPAP users ≥ 18 years of age were analyzed. The SNDS contains comprehensive, individualized, and anonymized data on health spending reimbursements for > 99% of all individuals living in France. OSA diagnosis was based on specific disease codes, whereas CPAP prescription was identified using specific treatment method codes. CPAP therapy termination was defined as the cessation of CPAP reimbursements triggered by the respiratory physician or sleep specialist in charge of follow-up. Patients who terminated therapy in the first year were propensity score matched with those who continued to use CPAP. The primary outcome was all-cause mortality. Three-year survival was visualized using Kaplan-Meier curves. Contributors to mortality also were determined.

RESULTS

Data from two matched groups each including 88,007 patients were included (mean age, 60 years; 64% men). Continuation of CPAP therapy was associated with a significantly lower risk of all-cause death compared with CPAP therapy termination (hazard ratio [HR], 0.61; 95% CI, 0.57-0.65; P < .01, log-rank test). Incident heart failure also was less common in patients who continued vs terminated CPAP therapy (HR, 0.77; 95% CI, 0.71-0.82; P < .01).

INTERPRETATION

These real-world data from a comprehensive, unbiased database highlight the potential for ongoing use of CPAP treatment to reduce all-cause mortality in patients with OSA.

Effect of Obstructive Sleep Apnea on Outcomes After Traumatic Brain Injury: A Retrospective Cohort Analysis

BACKGROUND

Traumatic brain injury (TBI) and obstructive sleep apnea (OSA) are common in the general population and are associated with significant morbidity and mortality. The objective of this study was to assess hospital outcomes of patients with TBI with and without a pre-existing OSA diagnosis.

METHODS

We retrospectively analyzed data from the National Inpatient Sample (NIS) database of adult patients aged ≥ 18 years with a primary diagnosis of TBI. In-hospital outcomes were assessed among patients with TBI with and without pre-existing OSA hospitalized between 2005 to 2015 in the United States. Propensity score matching and conditional logistic regression models were used to analyze in-hospital mortality, length of hospitalization, and in-hospital complications among patients with TBI with and without a pretrauma OSA diagnosis.

RESULTS

In our TBI cohort, the overall prevalence of diagnosed OSA was 0.90%. Patients with OSA were mostly obese or morbidly obese older men with high comorbidity burden and sustained more severe head injuries yet were less likely to undergo craniotomy or craniectomy. Following propensity score matching, the odds risk (OR) of in-hospital mortality was significantly lower in the OSA group with TBI (OR 0.58; p < 0.001). Compared with the non-OSA group, patients with OSA had significantly higher risk of respiratory complications (OR 1.23) and acute heart failure (OR 1.25) and lower risk of acute myocardial infarction (OR 0.73), cardiogenic shock (OR 0.34), and packed red blood cell transfusions (OR 0.79). Patients with OSA spent on average 0.3 days less (7.4 vs. 7.7 days) hospitalized compared with the non-OSA group.

CONCLUSIONS

Patients with TBI with underlying OSA diagnosis were older and had higher comorbidity burden; however, hospital mortality was lower. Pre-existing OSA may result in protective physiologic changes such as hypoxic-ischemic preconditioning especially to cardiac and neural tissues, which can provide protection following neurological trauma, which may lead to a reduction in mortality.

Longitudinal Analysis of Causes of Mortality in Continuous Positive Airway Pressure-treated Patients at the Population Level

Rationale: Randomized controlled trials do not support a role for continuous positive airway pressure (CPAP) in preventing major cardiovascular events or mortality in patients with obstructive sleep apnea (OSA). However, these trials' setting does not apply to most CPAP-treated patients. Objectives: We aimed to assess the effect of CPAP on mortality in real-world patients. Methods: We performed a population-based longitudinal observational study including all patients with OSA prescribed CPAP during 2011 in Catalonia, Spain, and non-OSA control subjects matched (1:2) by sex, 5-year age group, and region who were followed from 2011 to 2016. Results: A total of 9,317 CPAP-treated patients with OSA and 18,370 control subjects without OSA were included (median age, 67 [57-72] years; 74% male). During a median follow-up of 5.5 years, 2,301 deaths were recorded. After adjustment by a composite of diagnosed comorbidities and previous use of healthcare resources, CPAP-treated patients showed a lower risk of death than control subjects (hazard ratio [HR], 0.67; 95% confidence interval [CI], 0.61-0.74), with the association not being statistically significant in women. Cancer-related deaths were the main drivers of this association (men: HR, 0.44; 95% CI, 0.36-0.54; women: HR, 0.44; 95% CI, 0.28-0.68). No significant associations were found for cardiovascular-related deaths. CPAP-treated women had an increased risk of respiratory-related death (HR, 2.41; 95% CI, 1.37-4.23). Conclusions: CPAP-treated patients had a lower mortality rate than control subjects. This relationship was driven by cancer-related, but not cardiovascular-related, deaths. Results suggest a role for sex when prescribing CPAP, especially considering respiratory-related deaths, and foster a debate on the relationship between OSA and cardiovascular outcomes.

Sleep apnoea is a risk factor for severe COVID-19

Background

Obstructive sleep apnoea (OSA) is associated with higher body mass index (BMI), diabetes, older age and male gender, which are all risk factors for severe COVID-19.

We aimed to study if OSA is an independent risk factor for COVID-19 infection or for severe COVID-19.

Methods

OSA diagnosis and COVID-19 infection were extracted from the hospital discharge, causes of death and infectious diseases registries in individuals who participated in the FinnGen study (n=260 405). Severe COVID-19 was defined as COVID-19 requiring hospitalisation. Multivariate logistic regression model was used to examine association. Comorbidities for either COVID-19 or OSA were selected as covariates. We performed a meta-analysis with previous studies.

Results

We identified 445 individuals with COVID-19, and 38 (8.5%) of them with OSA of whom 19 out of 91 (20.9%) were hospitalised. OSA associated with COVID-19 hospitalisation independent from age, sex, BMI and comorbidities (p-unadjusted=5.13×10⁻⁵, OR-adjusted=2.93 (95% CI 1.02 to 8.39), p-adjusted=0.045). OSA was not associated with the risk of contracting COVID-19 (p=0.25). A meta-analysis of OSA and severe COVID-19 showed association across 15 835 COVID-19 positive controls, and n=1294 patients with OSA with severe COVID-19 (OR=2.37 (95% 1.14 to 4.95), p=0.021).

Conclusion

Risk for contracting COVID-19 was the same for patients with OSA and those without OSA. In contrast, among COVID-19 positive patients, OSA was associated with higher risk for hospitalisation. Our findings are in line with earlier works and suggest OSA as an independent risk factor for severe COVID-19.

What is a Clinically Meaningful Target for Positive Airway Pressure Adherence?

Although good adherence to continuous positive airway pressure (PAP) traditionally is defined as greater than or equal to 4 hours/night, the origins and rationale for this remain unclear. Research studies report variation in optimal duration of PAP adherence, depending on outcome of interest. Evidence demonstrates benefit with PAP for daytime sleepiness, quality of life, neurocognitive outcomes, depression, and hypertension, predominantly in symptomatic, moderate-severe obstructive sleep apnea. Recent randomized controlled trials, however, have failed to demonstrate a reduction in cardiovascular and mortality risks. This review explores the question of what can be considered a clinically meaningful outcome for PAP adherence.

Low long-term mortality in patients with sleep apnoea and positive airway pressure therapy: analysis of a large German healthcare database

Background

There are limited data on long-term mortality in sleep apnoea (SA) patients with and without positive airway pressure (PAP) therapy. This retrospective cohort study investigated long-term hospitalisation and mortality rates in SA patients from a German statutory health insurance (SHI) database who did versus did not receive PAP therapy.

Methods

Patients had continuous insurance coverage from 01 January 2008 to 31 December 2013, complete medical records and ≥1 SA-related diagnosis in 2009. Those receiving PAP were matched with a control group not treated with PAP. Outcomes (hospitalisations including stays in the sleep laboratory) were compared between groups the year prior to and the 4 years after SA diagnosis. Mortality was assessed in the 4 years after SA diagnosis.

Results

2176 PAP therapy recipients were matched with 2176 controls. The PAP group had a higher rate of hospitalisation in the year before SA diagnosis than the control group (80.2% vs. 26.6%; p = 0.0016). After diagnosis, the PAP group had a higher hospitalisation rate only in year 1 (p < 0.05), and average length of stay per hospitalisation was lower in the PAP group (p < 0.05 vs. control at years 1, 2 and 4). Cumulative all-cause mortality after year 3 (3.4% vs. 4.6%; p = 0.0287) and after year 4 (4.8% vs. 6.5%; p = 0.0175) was significantly lower in SA patients receiving PAP versus controls (relative risk reduction for death after 4 years: 25.5%).

Conclusion

This real-world cohort study showed an association between long-term PAP therapy use and lower mortality, a higher rate of hospitalisations before and shorter hospital stays after treatment initiation.

Treatment of obstructive sleep apnoea as primary or secondary prevention of cardiovascular disease: where do we stand now?

PURPOSE OF REVIEW

The aim of this study was to provide an update of the primary and secondary prevention of obstructive sleep apnoea (OSA) treatment on cardiovascular disease.

RECENT FINDINGS

Consistent evidence suggest that OSA can contribute to cardiovascular diseases, including hypertension, atrial fibrillation, coronary artery disease and stroke. In patients with no previous history of cardiovascular events (primary prevention scenario), observational studies suggest that continuous positive airway pressure (CPAP), the main treatment for OSA, is able to prevent hypertension incidence and to decrease nonfatal cardiovascular events in men and fatal cardiovascular events in men, women and elderly. In patients with a previous history of cardiovascular events (secondary prevention scenario), recent randomized trials showed that CPAP was not able to prevent a new cardiovascular event. These findings may suggest that in patients with high cardiovascular risk and multiple comorbidities, OSA may not have an incremental role on cardiovascular disease. However, a subanalysis from the same trials showed that good CPAP compliance was able to prevent cerebrovascular events.

SUMMARY

OSA may predispose to cardiovascular disease, but additional efforts for improving CPAP use or development of new treatments may help to understand the magnitude of OSA on cardiovascular disease.

Obstructive sleep apnea and comorbidities: a dangerous liaison

Obstructive sleep apnea (OSA) is a highly prevalent disease, and is traditionally associated with increased cardiovascular risk. The role of comorbidities in OSA patients has emerged recently, and new conditions significantly associated with OSA are increasingly reported. A high comorbidity burden worsens prognosis, but some data suggest that CPAP might be protective especially in patients with comorbidities. Aim of this narrative review is to provide an update on recent studies, with special attention to cardiovascular and cerebrovascular comorbidities, the metabolic syndrome and type 2 diabetes, asthma, COPD and cancer. Better phenotypic characterization of OSA patients, including comorbidities, will help to provide better individualized care. The unsatisfactory adherence to CPAP in patients without daytime sleepiness should prompt clinicians to examine the overall risk profile of each patient in order to identify subjects at high risk for worse prognosis and provide the optimal treatment not only for OSA, but also for comorbidities.