The clinical and hemodynamic characteristics of pulmonary hypertension in patients with OSA-COPD overlap syndrome

BACKGROUND

Our study aimed to assess the clinical and hemodynamic characteristics of pulmonary hypertension (PH) in patients with overlapping obstructive sleep apnea (OSA) and chronic obstructive pulmonary disease (COPD), referred to OSA-COPD overlap syndrome (OS).

METHODS

We enrolled a total of 116 patients with OS, COPD, or OSA who underwent right heart catheterization (RHC) due to suspected PH. We conducted a retrospective analysis of the clinical and hemodynamic characteristics of these patients.

RESULTS

Among the three groups (OS group, n = 26; COPD group, n = 36; OSA group, n = 54), the prevalence of PH was higher in the OS group (n = 17, 65.4%)compared to OSA group (n = 26,48.1%) and COPD group (n = 20,55.6 %). Among three groups with PH, the superior vena cava pressure (CVP) and right ventricular pressure (RAP) were higher in the OS group than in the OSA group (P < 0.05). Patients in the OS and COPD groups had higher pulmonary artery wedge pressure (PAWP) than in the OSA group (14.88 ± 4.79 mmHg, 13.45 ± 3.68 mmHg vs. 11.00 ± 3.51 mmHg, respectively, P < 0.05). OS patients with PH exhibited higher respiratory event index (REI), time spent with SpO2 <90%, oxygen desaturation index (ODI), minimal SpO2 (MinSpO2) and mean SpO2 (MSpO2) compared to OS patients without PH. After adjusting for potential covariates, we found that MinSpO2 (OR 0.937, 95 % CI 0.882-0.994, P = 0.032), MSpO2 (OR 0.805, 95% CI 0.682-0.949, P = 0.010), time spent with SpO2 <90% (OR 1.422, 95% CI 1.137-1.780, P = 0.002), and FEV1 % pred (OR 0.977, 95 % CI 0.962-0.993, P = 0.005) were related to the development of PH.

CONCLUSIONS

Patients with OS showed higher prevalence of PH, along with higher PAWP, CVP and RAP. Worse nocturnal hypoxemia was found in OS patients with PH.

Is the time below 90% of SpO2 during sleep (T90%) a metric of good health? A longitudinal analysis of two cohorts

BACKGROUND

Novel wireless-based technologies can easily record pulse oximetry at home. One of the main parameters that are recorded in sleep studies is the time under 90% of SpO2 (T90%) and the oxygen desaturation index 3% (ODI-3%). We assessed the association of T90% and/or ODI-3% in two different scenarios (a community-based study and a clinical setting) with all-cause mortality (primary outcome).

METHODS

We included all individuals from the Sleep Heart Health Study (SHHS, community-based cohort) and Santiago Obstructive Sleep Apnea (SantOSA, clinical cohort) with complete data at baseline and follow-up. Two measures of hypoxemia (T90% and ODI-3%) were our primary exposures. The adjusted hazard ratios (HRs) per standard deviation (pSD) between T90% and incident all-cause mortality (primary outcome) were determined by adjusted Cox regression models. In the secondary analysis, to assess whether T90% varies across clinical factors, anthropometrics, abdominal obesity, metabolic rate, and SpO2, we conducted linear regression models. Incremental changes in R2 were conducted to test the hypothesis.

RESULTS

A total of 4323 (56% male, median 64 years old, follow-up: 12 years, 23% events) and 1345 (77% male, median 55 years old, follow-up: 6 years, 11.6% events) patients were included in SHHS and SantOSA, respectively. Every 1 SD increase in T90% was associated with an adjusted HR of 1.18 [95% CI: 1.10-1.26] (p value < 0.001) in SHHS and HR 1.34 [95% CI: 1.04-1.71] (p value = 0.021) for all-cause mortality in SantOSA. Conversely, ODI-3% was not associated with worse outcomes. R2 explains 62% of the variability in T90%. The main contributors were baseline-mean change in SpO2, baseline SpO2, respiratory events, and age.

CONCLUSION

The findings suggest that T90% may be an important marker of wellness in clinical and community-based scenarios. Although this nonspecific metric varies across the populations, ventilatory changes during sleep rather than other physiological or comorbidity variables explain their variability.

Association between hypoxic burden and common cardiometabolic diseases in patients with severe obstructive sleep apnea

PURPOSE

To determine the possible associations between total sleep time spent with arterial oxygen saturation < 90% (T90) and comorbid cardiometabolic diseases (CMDs) in patients with severe obstructive sleep apnea (OSA).

METHODS

A retrospective review of the chart was conducted in patients with severe OSA diagnosed by in-lab polysomnography (PSG) between January 2018 and December 2019 at Siriraj Hospital. The patients were divided into two groups: hypoxic (T90 ≥ 10%) and nonhypoxic (T90 < 10%). The association between common CMDs including hypertension (HT), type 2 diabetes mellitus (T2DM), and impaired fasting glucose (IFG) was investigated and compared between the two groups.

RESULTS

Data were collected from 450 patients with severe OSA, 289 males/161 females with a mean age of 53.5 ± 14.2 years and an apnea-hypopnea index (AHI) of 49.6 events/h. Among these, 114 patients (25.3%) were defined as the hypoxic group (T90 ≥ 10%). When compared between the hypoxic and nonhypoxic groups, the patients in the hypoxic group were significantly younger and more obese, and had a higher proportion of male patients. The majority of patients (80%) had at least one CMD; however, the most common comorbidities significantly associated with hypoxic OSA (T90 ≥ 10%) were HT and IFG.

CONCLUSION

Hypoxic burden is significantly associated with an increased prevalence of HT and IFG in patients with severe OSA. T90 may be potentially useful for predicting CMDs in these patients. However, prospective studies are still required.

Nocturnal hypoxemia and prognosis in patients with acute symptomatic pulmonary embolism

BACKGROUND

Nocturnal hypoxemia has been associated with cardiovascular and non-cardiovascular morbidity and mortality. This study aimed to investigate the prognostic value of nocturnal hypoxemia among patients with hemodynamically stable acute symptomatic pulmonary embolism (PE).

METHODS

We performed an ad hoc secondary analysis of clinical data from a prospective cohort study. Nocturnal hypoxemia was measured by the percent sleep registry with oxygen saturation <90% [TSat90]). Outcomes assessed over the 30-days after the diagnosis of PE included PE-related death, other cardiovascular deaths, clinical deterioration requiring an escalation of treatment, recurrent venous thromboembolism (VTE), acute myocardial infarction [AMI], or stroke.

RESULTS

Of the 221 hemodynamically stable patients with acute PE from which the TSat90 could be calculated and did not receive supplemental oxygen, the primary outcome occurred in 11 (5.0%; 95% confidence interval [CI], 2.5% to 8.7%) within 30-days after the diagnosis of PE. When categorized by quartiles, TSat90 was not significantly associated with the occurrence of the primary outcome in unadjusted Cox regression analysis (hazard ratio, 0.96; 95% CI, 0.57 to 1.63; P = 0.88), or after adjustment for body mass index (adjusted hazard ratio, 0.97; 95% CI, 0.57 to 1.65; P = 0.92). When examined as a completely continuous variable (between 0 and 100), TSat90 was not associated with a significant increase in the adjusted hazard of 30-day primary outcome rates (hazard ratio, 0.97; 95% CI, 0.86 to 1.10; P = 0.66).

CONCLUSIONS

In this study, nocturnal hypoxemia did not identify stable patients with acute symptomatic PE at increased risk for adverse cardiovascular events.

Sleep-Disordered Breathing in Adults with Precapillary Pulmonary Hypertension: Prevalence and Predictors of Nocturnal Hypoxemia

PURPOSE

To evaluate the frequency of sleep-disordered breathing (SDB) and predictors of the presence of nocturnal desaturation in adults with pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension.

METHODS

Outpatients with a hemodynamic diagnosis of precapillary pulmonary hypertension who underwent portable polysomnography were evaluated. Diagnosis and severity of SDB were assessed using three well-established respiratory disturbance index (RDI) thresholds: 5.0/h, 15.0/h, and 30.0/h, while nocturnal hypoxemia was defined by the average oxygen saturation (SpO₂) < 90%. Multiple linear regression analysis evaluated the potential relationships among explanatory variables with the dependent variable (average SpO₂ values), with comparisons based on the standardized regression coefficient (β). The R-squared (R²; coefficient of determination) was used to evaluate the goodness-of-fit measure for the linear regression model.

RESULTS

Thirty-six adults were evaluated (69.4% females). The majority of the participants (75.0%) had SDB (26 with obstructive sleep apnea [OSA] and one with central sleep apnea [CSA]); while 50% of them had nocturnal hypoxemia. In the linear regression model (R² = 0.391), the mean pulmonary artery pressure [mPAP] (β - 0.668; p = 0.030) emerged as the only independent parameter of the average SpO₂.

CONCLUSION

Our study found that the majority of the participants had some type of SDB with a marked predominance of OSA over CSA, while half of them had nocturnal desaturation. Neither clinical and hemodynamic parameters nor the RDI was a predictor of nocturnal desaturation, except for mPAP measured during a right heart catheterization, which emerged as the only independent and significant predictor of average SpO₂.

The positional characteristics of patients with obstructive sleep apnea: a single institute retrospective study in Japan

Obstructive sleep apnea (OSA) causes sleep-disordered breathing (SDB) due to upper airway obstruction. The severity of OSA changes with position during sleep. Patients with marked significant improvement in apnea-hypopnea index (AHI) level by sleep position change are defined as ''positional patients'' (PP), while those without improvement are defined as ''non-positional patients'' (NPP). We aimed to verify their clinical characteristics. Between May 2008 and May 2020, 237 patients with OSA were registered retrospectively and classified into two groups: PP (n = 158) and NPP (n = 79). The differences in clinical background and full-night polysomnography (PSG) between the two groups were observed. A logistic regression analysis was conducted to identify the risk factors for severe AHI (≥ 30 events/h) in the PP group. Moreover, confounding factor-adjusted sub-analysis by a propensity score matching method was performed, and the PSG results were compared between the two groups. The PP group was older than the NPP group. Furthermore, the PP group had lower body mass index (BMI) and AHI levels compared with the NPP group. The independent risk factors for severe AHI in the PP group were BMI and being in the supine position during sleep. The PP group had a significantly milder nocturnal hypoxemia despite having no significant difference in AHI levels between the two groups. The characteristics of PP were old age, low BMI, and low AHI associated with milder nocturnal hypoxemia. Moreover, they were less likely to worsen with nocturnal hypoxemia compared with NPP having similar severity.

Influence of nocturnal hypoxemia on follow-up course after type B acute aortic syndrome

Introduction

Association between sleep nocturnal breathing disorders and acute aortic syndrome (AAS) has been described but mid-term data are scarce.

Objectives

We assessed the prognostic value of sleep apnea parameters and their relationship with aortic morphology after the onset of a type B AAS.

Methods

Between January 2010 and January 2018, sleep apnea screening in post type B AAS was prospectively performed. The association of sleep apnea parameters with aortic morphology and aortic expansion during follow-up was studied.

Results

Over the 8-year-study period, 103 patients were included, with a mean age of 57.8 ± 12.1 years old. Median follow-up was 25.0 months (11.0–51.0). Thirty-two patients (31%) required aortic stenting during the acute phase. In patients treated by aortic stenting, the descending thoracic aortic diameter was positively associated with a higher percentage of nocturnal time of saturation ≤ 90% after adjustment (p = 0.016). During follow-up, the nocturnal time of saturation ≤ 90% in patients treated by medical therapy was the only parameter associated with significant aortic expansion rate (r = 0.26, p = 0.04). Thirty-eight patients started and sustained nocturnal ventilation during follow-up. The association between aortic expansion rate and nocturnal time of saturation ≤ 90% did not persist during follow-up after adjustment on nocturnal ventilation initiation (r = 0.25, p = 0.056).

Conclusions

Nocturnal hypoxemia parameters are positively associated with the max onset aortic diameter and significant aortic growth after type B AAS. Nocturnal ventilation seems to mitigate aortic expansion during follow-up.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01778-y.

The association of obstructive sleep apnea with melanoma incidence and mortality: a meta-analysis of 5,276,451 patients

BACKGROUND

Melanoma is the most aggressive and lethal form of skin cancer. While emerging in-vivo evidence suggests that intermittent hypoxia, a hallmark feature of obstructive sleep apnea (OSA), may induce melanoma tumorigenesis, the epidemiological association between OSA and melanoma has been inconsistent.

METHODS

We performed a literature search of PubMed, Embase, Scopus and Cochrane Library from inception until 6 June 2021. Two reviewers independently selected randomized trials or observational studies that reported the association of OSA with melanoma incidence or mortality in adults, in comparison to participants with no OSA. Two reviewers independently extracted relevant data and assessed the quality of evidence using the GRADE framework and the Newcastle-Ottawa Scale (NOS). We pooled data using an inverse variance-weighted meta-analysis and ran pre-specified subgrourp analyses.

RESULTS

The meta-analysis included six studies out of 1897 records, comprising a combined cohort of 5,276,451 patients. All studies were adjusted for covariates, with majority of studies adjusting for age (N=5) and sex (N = 4). Compared to those without OSA, patients with OSA had 71% higher pooled hazards of melanoma (HR = 1.71; 95% CI: 1.08-2.69, I² = 99%). Subgroup analyses for studies with (1) median follow-up duration of at least five years, (2) prospective study design, (3) adjustment for obesity yielded HRs of 1.88 (95%CI:1.32-2.67, N = 5), 1.11 (95%CI:0.77-1.60, N = 2) and 1.52 (95%CI:0.75-3.08, N = 3) respectively. One study investigating the relationship between OSA and melanoma mortality detected no association. There were insufficient studies to assess publication bias.

CONCLUSIONS

Meta-analysis of mainly retrospective observational studies, with significant heterogeneity, suggests increased melanoma incidence in OSA patients. Future studies should prospectively explore the differential risk of melanoma for varying OSA severity, and whether timely OSA treatment may mitigate this risk.

Impact of nocturnal hypoxemia on the recurrence of atrial tachyarrhythmia after catheter ablation of atrial fibrillation

Factors causing atrial tachyarrhythmia recurrence after catheter ablation (CA) of atrial fibrillation (AF) remain undetermined. This study aimed to investigate the effect of nocturnal hypoxemia on the recurrence of atrial tachyarrhythmia after CA of AF. Among 594 patients with AF who underwent an ambulatory sleep study at the National Cerebral and Cardiovascular Center, Suita, Osaka, Japan (2014-2019), 365 underwent CA of AF; 290 patients who underwent CA were followed up for > 3 months. Multivariate Cox regression analysis was used to calculate hazard ratios (HRs) using clinical variables, to identify the independent predictors of atrial tachyarrhythmia recurrence after the final CA. Atrial tachyarrhythmia recurred in 45 of 290 (15.5%) patients during the median follow-up period of 479 days (interquartile range 225-1002). On the performing multivariate analysis of the data of patients who did not receive continuous positive airway pressure (CPAP), severe nocturnal hypoxemia [defined as the percentage of sleep time spent with SaO₂ of < 90% (T90) over 20%] [HR 8.53, 95% confidence interval (CI) 1.872-38.814; P < 0.01] and an 1 mL/m² increase in the left atrial volume index (HR 1.02, 95% CI 1.004-1.044; P = 0.02) were found to be independently associated with the recurrence of atrial tachyarrhythmia. In addition, the rates of freedom from atrial tachyarrhythmia after the final AF ablation with CPAP were significantly lower in the group with more severe nocturnal hypoxemia (Log-rank P = 0.03). In conclusion, it is necessary to consider both, AHI and nocturnal hypoxia while performing an ambulatory sleep apnea study. CA may be less effective in patients with more severe nocturnal hypoxia, despite the administration of CPAP.

Analysis of nocturnal desaturation waveforms using algorithms in patients with idiopathic pulmonary fibrosis

Purpose

Sleep-disordered breathing is recognized as a comorbidity in patients with idiopathic pulmonary fibrosis (IPF). Among them, nocturnal hypoxemia has been reported to be associated with poor prognosis and disease progression. We developed a diagnostic algorithm to classify nocturnal desaturation from percutaneous oxygen saturation (SpO₂) waveform patterns: sustained pattern, periodic pattern, and intermittent pattern. We then investigated the prevalence of nocturnal desaturation and the association between the waveform patterns of nocturnal desaturation and clinical findings of patients with IPF.

Methods

We prospectively enrolled patients with IPF from seven general hospitals between April 2017 and March 2020 and measured nocturnal SpO₂ and nasal airflow by using a home sleep apnea test. An algorithm was used to classify the types of nocturnal desaturation. We evaluated the association between sleep or clinical parameters and each waveform pattern of nocturnal desaturation.

Results

Among 60 patients (47 men) who met the eligibility criteria, there were 3 cases with the sustained pattern, 49 cases with the periodic pattern, and 41 cases with the intermittent pattern. Lowest SpO₂ during sleep and total sleep time spent with SpO₂ < 90% were associated with the sustained pattern, and apnea–hypopnea index was associated with the intermittent pattern.

Conclusion

We demonstrated the prevalence of each waveform and association between each waveform and sleep parameters in patients with IPF. This classification algorithm may be useful to predict the degree of hypoxemia or the complication of obstructive sleep apnea.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11325-021-02456-3.

[Resistant hypertension and Morgagni hernia: the importance of nocturnal hypoxaemia]

A 51-year-old woman consulted for resistant arterial hypertension despite adequate antihypertensive treatment. Physical examination and analytical study showed no relevant abnormalities, with pulse oximeter saturation of 95%. The study highlighted nocturnal respiratory polygraphy with data of mild intensity sleep apnoea syndrome, and severe nocturnal hypoxaemia (apnoea hypopnoea index per hours of sleep [AHI] 7.8; desaturation index per hour [ODI]: 12, 6. Oxygen- medium saturation: 89%, minimum saturation: 72%. CT90: 34.2%). The chest X-ray showed elevation of the right hemidiaphragm, and the chest computed tomography (CT) revealed a Morgagni hernia with a maximum diameter of 20 cm. After adjusting the antihypertensive treatment, the patient was referred to General Surgery for intervention. The onset of resistant hypertension secondary to severe nocturnal hypoxemia from a large Morgagni hernia has not been previously described in the literature.

Perioperative adherence to continuous positive airway pressure and its effect on postoperative nocturnal hypoxemia in obstructive sleep apnea patients: a prospective cohort study

Background

Although continuous positive airway pressure (CPAP) is the first line treatment for obstructive sleep apnea (OSA) patients, the perioperative adherence rate is unclear. The objective of this study was to determine the perioperative adherence rate of patients with OSA with a CPAP prescription and the effect of adherence on nocturnal oxygen saturation.

Methods

This prospective cohort study included adult surgical patients with a diagnosis of OSA with CPAP prescription undergoing elective non-cardiac surgery. Patients were divided into CPAP adherent and non-adherent groups based on duration of usage (≥ 4 h/night). Overnight oximetry was performed preoperatively and on postoperative night 1 and 2 (N1, N2). The primary outcome was adherence rate and the secondary outcome was nocturnal oxygen saturation.

Results

One hundred and thirty-two patients completed the study. CPAP adherence was 61% preoperatively, 58% on postoperative N1, and 59% on N2. Forty-nine percent were consistently CPAP adherent pre- and postoperatively. Using a linear fixed effects regression, oxygen desaturation index (ODI) was significantly improved by CPAP adherence (p = 0.0011). The interaction term CPAP x N1 was significant (p = 0.0015), suggesting that the effect of CPAP adherence varied on N1 vs preoperatively. There was no benefit of CPAP adherence on postoperative mean SpO₂, minimum SpO₂, and percentage of sleep duration with SpO₂ < 90%. Use of supplemental oxygen therapy was much lower in the CPAP adherent group vs non-adherent group (9.8% vs 46.5%, p <  0.001).

Conclusions

Among patients with a preoperative CPAP prescription, approximately 50% were consistently adherent. CPAP adherence was associated with improved preoperative ODI and the benefit was maintained on N1. These modest effects may be underestimated by a higher severity of OSA in the CPAP adherent group and a higher rate of oxygen supplementation in the non-adherent group.

Trial registration

ClinicalTrials.Gov registry (NCT02796846).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-021-01371-0.

Objectively assessed sleep-disordered breathing during pregnancy and infant birthweight

BACKGROUND

Sleep-disordered breathing (SDB) in pregnancy is associated with adverse maternal outcomes. The relationship between SDB and infant birthweight is unclear. This study's primary aim is to determine if objectively measured SDB in pregnancy is associated with infant birthweight.

METHODS

We measured SDB objectively in early (6-15 weeks' gestation) and mid (22-31 weeks' gestation) pregnancy in a large cohort of nulliparous women. SDB was defined as an Apnea-Hypopnea Index ≥5 and in secondary analyses we also examined measures of nocturnal hypoxemia. We used a modified Poisson regression approach to estimate relative risks (RR) of large-for-gestational-age (LGA: >90th percentile for gestational age) and small-for-gestational-age (SGA: <10th percentile for gestational age) birthweights.

RESULTS

The prevalence of early-pregnancy SDB was nearly 4%. The incidence of mid-pregnancy SDB was nearly 6.0%. The prevalence of LGA and SGA was 7.4% and 11.9%, respectively. Early-pregnancy SDB was associated with a higher risk of LGA in unadjusted models (RR 2.2, 95% CI 1.3-3.5) but not BMI-adjusted models (aRR 1.0, 95% CI 0.6-1.8). Mid-pregnancy SDB was not associated with SGA or LGA. Mid-pregnancy nocturnal hypoxemia (% of sleep time <90% oxygen saturation) and increasing nocturnal hypoxemia from early to mid-pregnancy were associated with a higher risk of LGA in BMI-adjusted models. SDB and nocturnal hypoxemia were not associated with SGA.

CONCLUSIONS

SDB in pregnancy was not associated with an increased risk of LGA or SGA birthweight, independent of BMI. Some measures nocturnal hypoxemia were associated with an increase in LGA risk, independent of BMI. ClinicalTrials.gov Registration number NCT02231398.

Association of parameters of nocturnal hypoxemia with diabetic microvascular complications: A cross-sectional study

AIMS

To examine the association between obstructive sleep apnea (OSA)-related nocturnal hypoxemia parameters and diabetic microvascular complications in patients with type 2 diabetes mellitus (T2DM).

METHODS

A total of 463 Chinese patients with T2DM underwent overnight polysomnography, followed by diagnosis of diabetic microvascular complications including diabetic peripheral neuropathy (DPN), diabetic retinopathy (DR) and diabetic nephropathy (DN). Parameters of nocturnal hypoxemia, including apnea-hypopnea index (AHI), oxygen desaturation index (ODI), time spent with SpO₂ < 90% (T90%) or <85% (T85%), mean SpO₂ and lowest SpO₂, were recorded.

RESULTS

AHI was independently associated with higher odds of DPN (OR 1.19; 95% CI, 1.05-1.36; P = 0.008) after adjustment for possible confounders. Moreover, patients with severe OSA (AHI ≥ 30 events/h) had higher likelihood of having DPN than those with mild OSA (OR 2.36; 95% CI, 1.31-4.25; P = 0.004). When combining DPN, DR and DN into an overall diabetic microvascular complication index, AHI was also independently associated with higher odds of having any diabetic microvascular complication (OR 1.21; 95% CI, 1.06-1.38; P = 0.006).

CONCLUSIONS

The AHI may be the OSA-related index that most strongly reflects the association of OSA and diabetic microvascular complications, compared with other OSA-related hypoxemia parameters.

Lung clearance index evaluation in detecting nocturnal hypoxemia in cystic fibrosis patients: Toward a new diagnostic tool

BACKGROUND

Nocturnal hypoxemia adversely affects outcomes in patients with cystic fibrosis (CF). Although an early detection of this abnormality may be desirable, still its predictability remains uncertain. The Lung Clearance Index (LCI) is a measure of lung ventilation distribution obtained from a multiple-breath washout technique (MBW), recently implemented in patients with CF. This study aimed to establish whether the LCI predicts nocturnal hypoxemia in patients with stable CF, with mild to moderate disease, and normal diurnal gas exchange.

METHODS

31 stable patients (15 males, mean age 17.4 ± 5.2 years) with mild to moderate CF, normoxic when awake, were enrolled. In all patients we performed nocturnal cardio-respiratory polygraphy, lung function measurement, and MBW test to derive LCI values.

RESULTS

LCI was abnormal in most of the patients and inversely correlated with mean nocturnal SpO₂ (r = -0.880 p < 0.01). A receiver operating characteristic (ROC) analysis, performed to assess whether LCI predicted nocturnal hypoxemia, revealed a high predictive accuracy of LCI for nocturnal desaturation (AUC = 0.96; Youden index = 0.79). Forced expiratory volume in 1 s (FEV₁) was predictive only in patients with more severe airway obstruction, with a moderate degree of accuracy (AUC 0.71).

CONCLUSIONS

The LCI showed a high effectiveness in predicting nocturnal hypoxemia in stable patients with CF, particularly when compared with a traditional parameter of lung function such as FEV₁.

Cardiometabolic comorbidities in obstructive sleep apnea patients are related to disease severity, nocturnal hypoxemia, and decreased sleep quality

BACKGROUND

Obstructive sleep apnea syndrome (OSA) is currently recognized as an independent risk factor for hypertension, arrhythmia, coronary heart disease, stroke, and metabolic disorders (e.g. diabetes, dyslipidemia). In clinical practice, apnea-hypopnea index (AHI) is the marker used to classify disease severity and guide treatment. However, AHI alone does not sufficiently identify OSA patients at risk for cardiometabolic comorbidities. With this in mind, the aim of this retrospective study was to determine whether some polysomnographic parameters (e.g. apnea-hypopnea duration, sleep structure, nocturnal hypoxemia) are specifically associated with cardiometabolic comorbidities in OSA.

METHODS

In this retrospective study, 1717 patients suffering from moderate/severe OSA were included between 2013 and 2017. Data on demographics, comorbidities, and polysomnographic characteristics were collected and analyzed to identify factors associated with cardiometabolic complications.

RESULTS

The medical files of 1717 patients (68% male) were reviewed. The mean AHI was 43.1 +/- 27.7 with 57.3% of patients suffering from severe OSA, and 52% from at least one cardiovascular comorbidity (CVCo). Diabetes affected 22% of the patients and 27% exhibited dyslipidemia. Patients affected by CVCos were older, and more often women and non-smokers. These patients also had worse sleep quality, and a more marked intermittent/global nocturnal hypoxemia. With regard to diabetes, diabetics were older, more often non-smoker, non-drinker women, and were more obese. These patients also exhibited more severe OSA, especially in non-REM (NREM) sleep, worse sleep quality, and a more marked intermittent/global nocturnal hypoxemia. Dyslipidemia was more frequent in the absence of alcohol consumption, and was associated with OSA severity, decreased sleep quality, and longer AH in REM sleep.

CONCLUSIONS

This study identifies demographic and polysomnographic factors associated with cardiometabolic comorbidities. Patients (especially women) suffering from more severe OSA, longer sleep apneas and hypopneas, worse sleep quality, and marked intermittent/global nocturnal hypoxemia are more likely to develop cardiometabolic comorbidities. This should stimulate clinicians to obtain adequate treatment in this population.

Improvement in Nocturnal Hypoxemia in Obese Patients with Obstructive Sleep Apnea after Bariatric Surgery: a Meta-Analysis

OBJECTIVE

To conduct a meta-analysis examining the effects of bariatric surgery on nocturnal hypoxemia in obese patients with obstructive sleep apnea (OSA).

METHODS

PubMed, EMBASE, Cochrane Library, and Web of Science were searched (the last search date was June 10, 2018) to identify relevant clinical studies. The mean arterial oxygen saturation (MeanSaO₂), nadir oxygen saturation (NadirSaO₂), apnea hypopnea index (AHI), and body mass index (BMI) data during the perioperative period were extracted and analyzed using a random effects model. Then, we performed subgroup and sensitivity analyses and calculated the publication bias to assess the between-study heterogeneity.

RESULTS

In total, 15 studies with 636 patients were included; 13 were prospective observational trials, 1 was a randomized controlled trial (RCT), and 1 was a retrospective trial. After surgery, the MeanSaO₂ and NadirSaO₂ increased by 1.36 [95% CI (0.72, 2.00)] and 1.08 [95% CI (0.68, 1.49)], respectively, and the AHI and BMI decreased by 1.11 [95% CI (0.82, 1.40)] and 1.97 [95% CI (1.67, 2.27)], respectively. However, the heterogeneity across all trials was high; we identified some of the sources of that heterogeneity through subsequent subgroup and sensitivity analyses.

CONCLUSIONS

Bariatric surgery is effective at improving nocturnal hypoxemia in obese patients with OSA; it also reduces body weight and the number of apnea events. More randomized controlled and comparative trials are necessary in the future to confirm our findings and to explore the potential underlying mechanisms.

Nocturnal Hypoxemia, But Not Sleep Apnea, Is Associated With a Poor Prognosis in Patients With Pulmonary Arterial Hypertension

BACKGROUND

Sleep apnea (SA) can cause repeated nocturnal arterial oxygen desaturation and result in acute increase in pulmonary arterial pressure (PAP). The presence of SA is associated with a poor prognosis in patients with chronic left-sided heart failure, but little is known for patients with pulmonary arterial hypertension (PAH). Methods and Results: We enrolled 151 patients with PAH (44±16 years old, male/female=37/114). They were all in the Nice Classification group 1 (idiopathic PAH/associated PAH=52/48%, mean PAP of 46±16 mmHg). They underwent right-heart catheterization and a sleep study with simplified polysomnography. Averaged percutaneous oxygen saturation (SpO₂) during sleep was measured and an apnea-hypopnea index >5 was defined as SA. SA was noted in 58 patients (obstructive SA/central SA: 29/29). Over an average follow-up of 1,170±763 days, 32 patients died. By Kaplan-Meier analysis, there was no significant difference in deaths of patients with and without SA (χ²=2.82, P=0.093). On the other hand, the mortality in patients with lower averaged SpO₂ was significantly higher than in those with higher averaged SpO₂ (χ²=14.7, P<0.001) and that was the only independent variable related to death in multivariate Cox proportional hazards analysis.

CONCLUSIONS

SA in patients with PAH was not associated with worse prognosis, unlike left ventricular heart failure, but nocturnal hypoxemia was related to poor prognosis.

Oxygen therapy in COPD patients with isolated nocturnal hypoxemia; comparison of quality of life and sleep between bronchitis and emphysema phenotype: A prospective observational study

BACKGROUND

COPD is a heterogeneous disease composed by two main phenotypes: bronchitis (COPDb) and emphysema (COPDe) with different clinical presentation, physiology, imaging, response to therapy and decline in lung function. The aim of this study is to evaluate whether nocturnal hypoxemic COPDb and COPDe have a different behaviour during sleep and the effect of nocturnal oxygen supplementation (nO₂LT).

MATERIALS AND METHODS

75 COPDb and 120 COPDe were enrolled. All patients performed polysomnography, Pittsburgh and Maugeri Foundation Respiratory Failure questionnaire, and pulmonary function before and after six months of nO₂LT.

RESULTS

At baseline, compared to COPDb, COPDe have decreased sleep efficiency (SE) (67.5±6% vs. 76.9±3% p<0.05) and higher arousals (A/I) (18.1±3 event/h vs. 8.7±1 event/h p<0.05). Oxygen desaturation index (ODI) was increased during REM (7.1±1 event/h vs. 2.3±0.5 event/h p<0.05). nO₂LT in COPDe improves SE (77±4% vs. 67.5±6% p<0.05) and decreases A/I (9±5 event/h vs. 18.1±3 event/h p<0.05). ODI during REM (3.5±2 event/h vs. 7.1±1 p<0.05) decreases and quality of life (QoL) improves (MFR-28 total 56±22 vs 45±20 p<0.05), due to an improvement in cognitive abilities (45±30 vs 33±31 p<0.05) and daily activities (61±29 vs 53±21 p>0.05). In COPDb nO₂LT reduces ST90 (15±6% vs. 43±8% p<0.05) less than in COPDe (15±6% vs. 8±4% p<0.05); improves A/I (10±2 event/h vs. 8.7±1 p<0.05) and there is no evidence of an improvement in QoL.

CONCLUSIONS

Six months of nO₂LT improve quality of life in COPDe, not in COPDb. We found a difference in sleep quality between COPDe and COPDb.

The association of obstructive sleep apnea (OSA) and nocturnal hypoxemia with the development of abnormal HbA1c in a population cohort of men without diabetes

AIM

To examine the relationship between indices of undiagnosed OSA and the development of abnormal glycaemic control in community-dwelling men free of diabetes.

METHODS

The Men, Androgens, Inflammation, Lifestyle, Environment, and Stress (MAILES) Study is a population-based cohort study in Adelaide, South Australia. Clinic visits at baseline (2002-06) and follow-up (2007-10) identified abnormal glycaemic metabolism [HbA1c 6.0 to <6.5% (42 to <48mmol/mol)] in men without diabetes. At follow-up (2010-11), n=837 underwent assessment of OSA by full in-home unattended polysomnography (Embletta X100).

RESULTS

Development of abnormal glycaemic metabolism over 4-6 years (n=103 "incident" cases, 17.0%) showed adjusted associations [odds ratio (95% CI)] with the 1st [1.7 (0.8-3.8)], 2nd [2.4 (1.1-4.9)], and 3rd [2.3 (1.1-4.8)] quartiles of mean oxygen saturation (SaO2) compared to the highest quartile. Prevalent abnormal glycaemic metabolism (n=140, 20.8%) was independently associated with the third and fourth quartiles of percentage of sleep time with oxygen saturation <90% and lowest quartile of mean SaO2. Linear regression analysis showed a significant reduction in HbA1c [unstandardized B, 95% CI: -0.02 (-0.04, -0.002), p=0.034] per percentage point increase in mean SaO2. OSA as measured by the apnea-hypopnea index showed no adjusted relationship with abnormal glycaemic metabolism.

CONCLUSIONS

Development of abnormal glycaemic metabolism was associated with nocturnal hypoxemia. Improved management of OSA and glycaemic control may occur if patients presenting with one abnormality are assessed for the other.

Does AHI Value Enough for Evaluating the Obstructive Sleep Apnea Severity?

Obstructive sleep apnea/hypopnea syndrome (OSAHS) is an important and more common public health problem with increasing incidence. Polysomonography (PSG) is the gold standard test in OSAHS diagnosis. Apnea-hypopnea index (AHI) is the main parameter of PSG, which is correlated with OSAHS severity. The main complaint of OSAHS patients is daytime sleepiness and the Epworth Sleepiness Scale (ESS) used for evaluation of disease severity. The correlation of AHI with daytime sleepiness and ESS is well known. But there are many patients, which have uncorrelated daytime sleepiness with AHI. This data calls this hypothesis; Are there any other parameters which may affect daytime sleepiness. 648 patients with complaining of snoring and apnea were evaluated by polysomnography and anthropometric measurements. The cut-off value of ESS was accepted 10 as an indicator of severe daytime sleepiness. Patients were divided to groups with the aim of homogenization, according to AHI values. The patients with similar AHI values were analyzed according to their ESS scores. BMI and neck circumference were elevated in daytime sleepiness patients. The nocturnal hypoxemia markers; apnea number/index, maximum duration of apnea, at least SO2 concentration, duration of SO2 less than 90 % were much effected in the group of daytime sleepiness. Beside the fact that our research, AHI is not enough for predicting the daytime sleepiness; anthropometric measurements and the nocturnal hypoxemia markers should be evaluated.