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Summary: We recruited 5,970 hypertensive patients with obstructive sleep apnea (OSA) on current antihypertensive treatment from the European Sleep Apnea Database (ESADA) cohort. The group was subdivided into those receiving monotherapy (n = 3,594) and those receiving dual combined therapy (n = 2,376). We studied how major OSA confounders like age, gender, and body mass index as well as the degree of sleep apnea modified office systolic and diastolic blood pressure. Beta‐blockers alone or in combination with a diuretic were compared with other antihypertensive drug classes. Monotherapy with beta‐blocker was associated with lower systolic blood pressure, particularly in non‐obese middle‐aged males with hypertension. Conversely, the combination of a beta‐blocker and a diuretic was associated with lower systolic and diastolic blood pressure in hypertensive patients with moderate–severe OSA. Systolic blood pressure was better controlled in female patients using this combined treatment. Our cross‐sectional data suggest that specific clinical characteristics and type of antihypertensive medication influence the degree of blood pressure control in hypertensive OSA patients. Controlled trials are warranted. [ABSTRACT FROM AUTHOR]

Summary: Obstructive sleep apnea is linked to severe health consequences such as hypertension, daytime sleepiness, and cardiovascular disease. Nearly a billion people are estimated to have obstructive sleep apnea with a substantial economic burden. However, the current diagnostic parameter of obstructive sleep apnea, the apnea–hypopnea index, correlates poorly with related comorbidities and symptoms. Obstructive sleep apnea severity is measured by counting respiratory events, while other physiologically relevant consequences are ignored. Furthermore, as the clinical methods for analysing polysomnographic signals are outdated, laborious, and expensive, most patients with obstructive sleep apnea remain undiagnosed. Therefore, more personalised diagnostic approaches are urgently needed. The Sleep Revolution, funded by the European Union's Horizon 2020 Research and Innovation Programme, aims to tackle these shortcomings by developing machine learning tools to better estimate obstructive sleep apnea severity and phenotypes. This allows for improved personalised treatment options, including increased patient participation. Also, implementing these tools will alleviate the costs and increase the availability of sleep studies by decreasing manual scoring labour. Finally, the project aims to design a digital platform that functions as a bridge between researchers, patients, and clinicians, with an electronic sleep diary, objective cognitive tests, and questionnaires in a mobile application. These ambitious goals will be achieved through extensive collaboration between 39 centres, including expertise from sleep medicine, computer science, and industry and by utilising tens of thousands of retrospectively and prospectively collected sleep recordings. With the commitment of the European Sleep Research Society and Assembly of National Sleep Societies, the Sleep Revolution has the unique possibility to create new standardised guidelines for sleep medicine. [ABSTRACT FROM AUTHOR]

Summary: Sleep is controlled by a circadian rhythmicity, via a reduction of arousal‐promoting neuromodulatory activity, and by accumulation of somnogenic factors in the interstitial fluid of the brain. Recent experiments in mice suggest that a reduced neuronal excitability caused by a reduced concentration of potassium in the brain, concomitant with an increased concentration of calcium and magnesium, constitutes an important mediator of sleep. In the present study, we examined whether such changes in ion concentrations could be detected in the cerebrospinal fluid of healthy humans. Each subject underwent cerebrospinal fluid collection at three occasions in a randomized order: at 15:00 hours–17:00 hours during waking, at 06:00 hours–07:00 hours immediately following 1 night of sleep, and at 06:00 hours–07:00 hours following 1 night of sleep deprivation. When compared with wakefulness, both sleep and sleep deprivation produced the same effect of a small (0.1 mm, about 3%), but robust and highly significant, reduction in potassium concentration. Calcium and magnesium concentrations were unchanged. Our results support a circadian modulation of neuronal excitability in the brain mediated via changes of the interstitial potassium concentration. [ABSTRACT FROM AUTHOR]

Summary: Patients with obstructive sleep apnea (OSA) are at increased risk of developing metabolic disease such as diabetes. The effects of positive airway pressure on glycemic control are contradictory. We therefore evaluated the change in glycated hemoglobin (HbA1c) in a large cohort of OSA patients after long‐term treatment with positive airway pressure. HbA1c levels were assessed in a subsample of the European Sleep Apnea Database [n=1608] at baseline and at long‐term follow up with positive airway pressure therapy (mean 378.9±423.0 days). In a regression analysis, treatment response was controlled for important confounders. Overall, HbA1c decreased from 5.98±1.01% to 5.93±0.98% (p=0.001). Patient subgroups with a more pronounced HbA1c response included patients with diabetes (−0.15±1.02, p=0.019), those with severe OSA baseline (−0.10±0.68, p=0.005), those with morbid obesity (−0.20±0.81, p<0.001). The strongest HbA1c reduction was observed in patients with a concomitant weight reduction >5 kilos (−0.38±0.99, p<0.001). In robust regression analysis, severe OSA (p=0.038) and morbid obesity (p=0.005) at baseline, and weight reduction >5 kilos (p<0.001) during follow up were independently associated with a reduction of HbA1c following PAP treatment. In contrast, PAP treatment alone without weight reduction was not associated with significant Hb1Ac reduction. In conclusion, positive airway pressure therapy is associated with HbA1c reduction in patients with severe OSA, in morbidly obese patients. and most obviously in those with significant weight lost during the follow‐up. Our study underlines the importance to combine positive airway pressure use with adjustments in lifestyle to substantially modify metabolic complications in OSA. [ABSTRACT FROM AUTHOR]

Summary: Recent studies indicate that ambient temperature may modulate obstructive sleep apnoea (OSA) severity. However, study results are contradictory warranting more investigation in this field. We analysed 19,293 patients of the European Sleep Apnoea Database (ESADA) cohort with restriction to the three predominant climate zones according to the Köppen–Geiger climate classification: Cfb (warm temperature, fully humid, warm summer), Csa (warm temperature, summer dry, hot summer), and Dfb (snow, fully humid, warm summer). Average outside temperature values were obtained and several hierarchical regression analyses were performed to investigate the impact of temperature on the apnea–hypopnea index (AHI), oxygen desaturation index (ODI), time of oxygen saturation <90% (T90) and minimum oxygen saturation (MinSpO2) after controlling for confounders including age, body mass index, gender, and air conditioning (A/C) use. AHI and ODI increased with higher temperatures with a standardised coefficient beta (β) of 0.28 for AHI and 0.25 for ODI, while MinSpO2 decreased with a β of −0.13 (all results p <.001). When adjusting for climate zones, the temperature effect was only significant in Cfb (AHI: β = 0.11) and Dfb (AHI: β = 0.08) (Model 1: p <.001). The presence of A/C (3.9% and 69.3% in Cfab and Csa, respectively) demonstrated only a minor increase in the prediction of the variation (Cfb: AHI, R2 +0.003; and Csa: AHI, R2 +0.007; both p <.001). Our present study indicates a limited but consistent influence of environmental temperature on OSA severity and this effect is modulated by climate zones. [ABSTRACT FROM AUTHOR]

Whole blood carbonic anhydrase activity (CAa) is increased in patients with obstructive sleep apnea (OSA). Our study investigated the influence of positive airway pressure (PAP) or CA inhibitor acetazolamide (ACT) therapy on CAa, OSA and blood pressure. Thirty‐three OSA patients (21 hypertensive, body mass index (BMI) 37 ± 7 kg/m2 and apnea–hypopnea index (AHI) of 47 ± 31 events/hr) were followed‐up after PAP treatment (compliance, 4.7 ± 1.5 hr/day; duration, median 6 [IQR 6,6] months) (Cohort A). A second OSA Cohort (B) contained nine hypertensive patients (BMI, 29 ± 4 kg/m2; AHI, 39 ± 20 events/hr) with 2‐week treatment of ACT, PAP or ACT + PAP in an open crossover study. CAa was assessed at baseline and at the end of each treatment period. In Cohort A, baseline CAa was higher in hypertensive, compared with normotensive, patients (1,033 ± 204 versus 861 ± 201 units, p =.028). PAP treatment reduced systolic/diastolic blood pressure but not CAa (−9 ± 11/−5 ± 7 mmHg and −20 ± 289 units, p <.001, <.001 and.70). In Cohort B, blood pressure was reduced in both ACT‐treated groups (−10 ± 10/−5 ± 7 mmHg, p =.043 and.019; and −5 ± 5/−13 ± 13 mmHg, p <.001 and.009). AHI was reduced in both groups: ACT only, −17 ± 9 events/hr p =.001; and ACT + PAP, −39 ± 19 events/hr, p <.001. PAP did not change CAa (p =.98) but activity tended to decrease after ACT with or without PAP (p =.081 and.056). CAa is elevated in hypertensive OSA patients. Long‐term PAP reduced blood pressure without affecting CAa. ACT reduced blood pressure and CAa. Increased CAa may constitute a physiological characteristic in OSA, contributing to comorbid hypertension. [ABSTRACT FROM AUTHOR]

The cross-sectional relationship of obstructive sleep apnea with moderate to severe chronic kidney disease, defined as an estimated glomerular filtration rate <60 mL min−1∙1.73 m−2, was investigated in a large cohort of patients with suspected obstructive sleep apnea studied by nocturnal polysomnography or cardiorespiratory polygraphy. Data were obtained from the European Sleep Apnea Database, where information from unselected adult patients with suspected obstructive sleep apnea afferent to 26 European sleep centres had been prospectively collected. Both the Modification of Diet in Renal Disease and the Chronic Kidney Disease-Epidemiology Collaboration equations were used for the assessment of estimated glomerular filtration rate. The analysed sample included 7700 subjects, 71% male, aged 51.9 ± 12.5 years. Severe obstructive sleep apnea (apnea-hypopnea index ≥30) was found in 34% of subjects. The lowest nocturnal oxygen saturation was 81 ± 10.2%. Chronic kidney disease prevalence in the whole sample was 8.7% or 6.1%, according to the Modification of Diet in Renal Disease or the Chronic Kidney Disease-Epidemiology Collaboration equations, respectively. Subjects with lower estimated glomerular filtration rate were older, more obese, more often female, had worse obstructive sleep apnea and more co-morbidities ( P < 0.001, each). With both equations, independent predictors of estimated glomerular filtration rate <60 were: chronic heart failure; female gender; systemic hypertension; older age; higher body mass index; and worse lowest nocturnal oxygen saturation. It was concluded that in obstructive sleep apnea, chronic kidney disease is largely predicted by co-morbidities and anthropometric characteristics. In addition, severe nocturnal hypoxaemia, even for only a small part of the night, may play an important role as a risk factor for kidney dysfunction. [ABSTRACT FROM AUTHOR]

Summary Obstructive sleep apnea diagnosis is based on the manual scoring of respiratory events. The agreement in the manual scoring of the respiratory events lacks an in‐depth investigation as most of the previous studies reported only the apnea–hypopnea index or overall agreement, and not temporal, second‐by‐second or event subtype agreement. We hypothesized the temporal and subtype agreement to be low because the event duration or subtypes are not generally considered in current clinical practice. The data comprised 50 polysomnography recordings scored by 10 experts. The respiratory event agreement between the scorers was calculated using kappa statistics in a second‐by‐second manner. Obstructive sleep apnea severity categories (no obstructive sleep apnea/mild/moderate/severe) were compared between scorers. The Fleiss' kappa value for binary (event/no event) respiratory event scorings was 0.32. When calculated separately within N1, N2, N3 and R, the Fleiss' kappa values were 0.12, 0.23, 0.22 and 0.23, respectively. Binary analysis conducted separately for the event subtypes showed the highest Fleiss' kappa for hypopneas to be 0.26. In 34% of the participants, the obstructive sleep apnea severity category was the same regardless of the scorer, whereas in the rest of the participants the category changed depending on the scorer. Our findings indicate that the agreement of manual scoring of respiratory events depends on the event type and sleep stage. The manual scoring has discrepancies, and these differences affect the obstructive sleep apnea diagnosis. This is an alarming finding, as ultimately these differences in the scorings affect treatment decisions. [ABSTRACT FROM AUTHOR]

Summary In‐laboratory polysomnography, the gold‐standard for diagnosing sleep disorders, is resource‐demanding and not conducive to multiple night evaluations. Ambulatory polysomnography, especially when self‐applied, could be a viable alternative. This study aimed to assess the feasibility and reliability of self‐applied polysomnography over three consecutive nights in untrained participants, assessing: technical success rate; comparing sleep diagnostic variables from single and multiple nights; and evaluating participants' subjective experience. Data were collected from 78 participants (55.1% females) invited to test a self‐applicable polysomnography device for three consecutive nights at home. The technical success rate for valid sleep recordings was 82.5% out of 234 planned study nights, with 87.2% of participants obtaining at least two valid nights. Misclassification of obstructive sleep apnea severity was higher in participants with mild OSA (21.4%) compared with those with moderate‐to‐severe obstructive sleep apnea or no obstructive sleep apnea. Sleep efficiency and wake after sleep onset showed improvement from Night 1 to Night 3 (p < 0.001), and the mean polysomnography set‐up time decreased significantly over this period. Participants reported moderate‐to‐high satisfaction with the device (System Usability Scale score 71.2 ± 12.4). The findings suggest that self‐applied polysomnography is a feasible diagnostic method for untrained individuals at risk for sleep disorders, and that multiple night assessments can improve diagnostic precision for mild obstructive sleep apnea cases. [ABSTRACT FROM AUTHOR]

Summary: The effect of positive airway pressure treatment on weight and markers of central obesity in patients with obstructive sleep apnea remains unclear. We studied the change in body weight and anthropometric measures following positive airway pressure treatment in a large clinical cohort. Patients with obstructive sleep apnea with positive airway pressure treatment from the European Sleep Apnea Database registry (n = 1,415, 77% male, age 54 ± 11 [mean ± SD] years, body mass index 31.7 ± 6.4 kg/m2, apnea–hypopnea index 37 ± 24 n per hr, Epworth Sleepiness Scale 10.2 ± 5.0) were selected. Changes in body mass index and neck/waist/hip circumferences at baseline and at follow‐up visit were analysed. Overall, body mass index (0.0 [95% confidence interval, −0.1 to 0.2] kg/m2) and neck circumference (0.0 (95% confidence interval, −0.1 to 0.1] cm) were unchanged after positive airway pressure treatment compared with baseline (follow‐up duration 1.1 ± 1.0 years and compliance 5.2 ± 2.1 hr per day). However, in non‐obese (body mass index <30 kg/m2) patients, positive airway pressure treatment was associated with an increased body mass index and waist circumference (0.4 [0.3–0.5] kg/m2 and 0.8 [0.4–1.2] cm, respectively, all p < 0.05), and weight gain was significantly associated with higher positive airway pressure compliance and longer positive airway pressure treatment duration. In the obese subgroup, body mass index was reduced after positive airway pressure treatment (−0.3 [−0.5 to −0.1] kg/m2, p < 0.05) mainly in patients with a strong reduction in Epworth Sleepiness Scale. In conclusion, positive airway pressure therapy was not found to systematically change body mass index in the European Sleep Apnea Database cohort, but the response was heterogeneous. Our findings suggest that weight gain may be restricted to an obstructive sleep apnea phenotype without established obesity. Lifestyle intervention needs to be considered in both lean and obese patients with obstructive sleep apnea receiving positive airway pressure treatment. [ABSTRACT FROM AUTHOR]