Search Results (515)

Background: Obstructive sleep apnea syndrome (OSA) is a significant disorder characterized by recurrent upper airway obstruction. Cervical vertebral alignment and lordosis angles may influence airway cross-sectional area. This study aimed to investigate the relationship between cervical lordosis angles and disease severity in patients with OSA. Methods: The study included 30 patients with OSA (mild n = 6, moderate n = 11, severe n = 13 based on Apnea–Hypopnea Index [AHI]) and 30 non-OSA controls presenting with mechanical neck pain. C1–C2, C1–C7, and C2–C7 angles were measured using the Cobb method on lateral cervical cephalometric radiographs. Additional soft tissue and airway parameters — prevertebral soft-tissue thickness at C2 (PST-C2) and C4 (PST-C4), posterior airway space (PAS), and mandibular plane–hyoid distance (MP-H)— were measured as anatomical surrogates given the unavailability of BMI data. Multiple linear regression (ANCOVA) models adjusting for age and sex were constructed for each cervical angle. Results: All cervical angles were significantly reduced in patients with OSA compared to controls (C1–C2: 25.51 ± 6.47° vs 33.3 ± 4.44°; C1–C7: 35.0 ± 11.9° vs 51.2 ± 7.34°; C2–C7: 9.19 ± 10.6° vs 19.9 ± 5.05°; all p < 0.001). Within the OSA group, a significant moderate negative correlation was found between AHI and the C2–C7 angle (ρ = − 0.522, p = 0.003), while the C1–C7 angle showed a borderline association (ρ = −0.361, p = 0.050) and C1–C2 did not reach significance (ρ = +0.118, p = 0.534). After adjustment for age and sex, group membership (OSA vs. control) remained a strong, independent predictor of all three cervical angles (all p < 0.001), whereas neither age nor sex was a significant predictor (all p > 0.34). PST-C2 was significantly higher in the OSA group (4.93 ± 1.06 mm vs. 4.30 ± 0.70 mm, p = 0.017), whereas PST-C4, PAS, and MP-H did not differ significantly between groups (all p > 0.05), and none of these parameters correlated significantly with the C2–C7 angle. Conclusions: Significant cervical lordosis loss was observed in patients with OSA compared to non-OSA controls, with the C2–C7 angle showing a significant negative correlation with AHI within the OSA group; this association remained robust after adjustment for age and sex. Supplementary soft tissue and airway measurements showed no significant correlation with cervical alignment or AHI, suggesting the observed association is not simply attributable to regional soft-tissue thickness or airway narrowing; however, without direct BMI data, a confounding role of systemic adiposity cannot be excluded. These findings suggest a potential association between cervical posture and upper airway dynamics; however, larger prospective studies are required to confirm clinical utility. Full article

Background: Whether the physiological response during positive airway pressure (PAP) titration predicts adherence independently of baseline severity is unclear. Methods: In 304 patients who underwent manual PAP titration at a tertiary university hospital between 2020 and 2022, adherence was defined by Korean reimbursement criteria (≥4 h/night on ≥70% of nights within any consecutive 30-day period during the initial 90 days). Titration parameters were compared using tests appropriate to each distribution and entered into logistic regression adjusted for age, sex, body mass index and baseline apnea–hypopnea index (AHI), with bootstrap validation. Results: Adherent (n = 238) and non-adherent (n = 66) groups had comparable baseline severity. Three titration parameters differed: AHI reduction rate (p = 0.033), lowest oxygen saturation (SpO₂; p = 0.010) and rapid eye movement-sleep proportion (p = 0.021). Adding these parameters to a confounder-only model raised the area under the curve from 0.566 to 0.683 (p < 0.001; optimism-corrected, 0.632). Adjusted for confounders alone, all three were significant, but with mutual adjustment only the lowest SpO₂ remained independent (odds ratio, 1.117 per 1%; 95% CI, 1.028–1.214). Conclusions: Among the physiological parameters recorded during PAP titration, the lowest SpO₂ was the most robust predictor of short-term adherence, independent of both baseline disease severity and baseline hypoxemia. Prospective validation is required. Full article

Background: In children with medical complexity (CMC), respiratory involvement represents one of the main causes of morbidity. Early recognition of nocturnal hypoventilation or sleep-disordered breathing (SDB) may allow timely intervention and reduce perioperative respiratory complications. This study aimed to evaluate the role of sleep studies in guiding clinical decision-making and perioperative respiratory management in CMC patients undergoing spinal arthrodesis for scoliosis correction. Methods: We retrospectively analysed clinical data from 357 patients (196 females) who underwent scoliosis surgery between 20 November 2012 and 11 June 2024. All patients received a standardized preoperative respiratory assessment at the Pulmonology Unit of IRCCS Burlo Garofolo. Results: Patients were classified into seven diagnostic groups, including neurological, neuromuscular, cerebral palsy, malformative, and other complex conditions. Median age at surgery was 12 years (range 2–22). Sleep studies were performed in 119 patients and identified abnormalities suggestive of sleep-disordered breathing or nocturnal hypoventilation, including elevated apnea–hypopnea index, oxygen desaturation, or abnormal transcutaneous carbon dioxide levels. Before surgery, 20 patients were receiving non-invasive ventilation nIV), initiated based on sleep study findings or pulmonary function impairment, while two patients were supported with continuous positive airway pressure (CPAP). Median Paediatric Intensive Care Unit (PICU) stay was 4.0 days (IQR 3.0–5.5 days; range 1–23), with no statistically significant differences across diagnostic categories (p = 0.12). Postoperatively, respiratory support was frequently required, including invasive mechanical ventilation, NIV, or CPAP, but the duration of invasive ventilation was 15.5 h (range 1–36). Only one patient required tracheostomy, and no perioperative deaths occurred. Conclusions: In CMC undergoing spinal arthrodesis, preoperative sleep studies significantly influence the clinical decision-making process and support perioperative respiratory assessment by identifying occult respiratory vulnerability and informing tailored ventilatory strategies. While associated with structured management pathways, the prospective impact of sleep-guided interventions on postoperative clinical outcomes remains to be confirmed through controlled studies. Full article

Background/Objectives: Obstructive sleep apnea (OSA) is traditionally classified according to the apnea–hypopnea index (AHI), although AHI alone does not fully capture the heterogeneity of disease severity. This study introduces a novel polysomnography-derived biomarker, the Sleep Disturbance Ratio (SDR), and evaluates its contribution to OSA severity classification using explainable machine learning approaches. Methods: A retrospective study was conducted using polysomnographic data from 767 adults who underwent overnight sleep studies. SDR was calculated as the logarithmic ratio between light sleep (N1 + N2) and restorative sleep (N3 + REM). Predictive models were trained and evaluated using four established machine learning algorithms: Decision Tree, Random Forest, Extreme Gradient Boosting (XGBoost), and Artificial Neural Network (ANN). Model performance was assessed using accuracy, Cohen’s kappa, F1-score, multiclass AUC, ROC analysis, feature importance ranking, partial dependence plots, and clinical risk mapping. Results: Although SDR did not differ significantly across conventional OSA severity groups in univariate analysis (p = 0.77), explainable machine learning analyses consistently demonstrated that increasing SDR was associated with a higher probability of severe OSA, particularly in combination with lower mean oxygen saturation. SDR also showed strong physiological relevance by correlating positively with N2 sleep (r = 0.85) and negatively with N3 sleep (r = −0.83), supporting its role as a biomarker of sleep fragmentation. Among the predictive models, Random Forest achieved the highest classification accuracy (75.0%), whereas XGBoost demonstrated the best multiclass discrimination (AUC = 0.895) and the highest ROC performance for severe OSA (AUC = 0.962). ESS remained the most influential predictor across all models. Conclusions: This study introduces SDR as a novel polysomnography-derived biomarker that captures sleep architecture disruption beyond conventional AHI-based assessment. Although SDR is not an independent diagnostic marker, explainable machine learning analyses demonstrated that it provides complementary physiological information for OSA severity classification, particularly when integrated with oxygenation parameters. Full article

Obstructive sleep apnea (OSA) is associated with renin–angiotensin–aldosterone system (RAAS) dysregulation. This study examined the relationship between salivary aldosterone and OSA severity, identified predictors of salivary aldosterone, evaluated the moderating role of mean arterial pressure (MAP), and compared the diagnostic performance of salivary aldosterone with the STOP-BANG questionnaire. This cross-sectional study included 67 adults grouped as healthy or mild OSA (apnea–hypopnea index [AHI] < 15; n = 34) versus moderate-to-severe OSA (AHI ≥ 15; n = 33). Morning salivary aldosterone was measured using enzyme-linked immunosorbent assay. Generalized linear models assessed independent predictors, MAP moderation was tested using PROCESS Model 1, and diagnostic performance was evaluated using receiver operating characteristic analysis. Salivary aldosterone did not differ between OSA severity groups and showed poor diagnostic performance. Age was negatively associated with aldosterone levels, while MAP moderated the relationship between AHI and salivary aldosterone. In contrast, the STOP-BANG questionnaire demonstrated acceptable discriminative ability and significantly higher specificity. Salivary aldosterone is not a reliable standalone OSA screening biomarker. However, MAP moderated the OSA–aldosterone relationship, suggesting potential utility in OSA patients with elevated MAP. Age independently predicted lower aldosterone, likely reflecting age-related RAAS decline. These findings support selective utility of salivary aldosterone in OSA patients with elevated blood pressure. Full article

Background: Obstructive sleep apnea (OSA) has been implicated in declarative memory impairment. Here, we evaluated immediate recall and overnight declarative memory in patients with suspected OSA before and after standard clinical management in a longitudinal cohort of 265 patients. Methods: A nocturnal polysomnographic study (PSG) was performed at baseline and repeated six months later. The Pictorial-Based Declarative Memory Questionnaire (PDMQ) was administered and consisted of four learning trials followed by free-recall 10 min before PSG and the following morning upon awakening. The primary cognitive endpoint was the change in pictorial declarative memory performance from baseline to 6-month follow-up, expressed as the number of correctly recalled items on the PDMQ. Results: Both immediate and delayed recall performances significantly improved in the no OSA/mild OSA and severe OSA groups, whereas only immediate recall improved in the moderate OSA group. In the severe group, comparisons between patients whose apnea–hypopnea index decreased to <30 events/hour and those whose AHI remained >30 revealed significant cognitive improvements in both subgroups, particularly in initial and late trials (Trials 1, 2, 5, 6). In multivariable models, baseline PDMQ performance and indices of SpO₂ desaturation and sleep fragmentation emerged as independent predictors of change in declarative memory. Conclusions: These findings suggest that routine clinical management of patients with OSA was accompanied by modest, albeit statistically significant improvements in declarative memory, and that both intermittent hypoxia and sleep fragmentation play important roles in memory change. Full article

Background/Objectives: Pediatric obstructive sleep apnea (OSA), particularly when accompanied by mandibular retrognathia, presents as a complex, multifactorial condition. Dentofacial orthopedic treatment (DOT) has gained increasing clinical attention; however, high-level evidence specifically demonstrating its efficacy in pediatric OSA remains scarce. This study aimed to evaluate the efficacy of DOT and AT in managing mild to moderate OSA in children with mandibular retrognathia. Methods: This open-label, randomized controlled clinical trial recruited 93 children aged 7–10 years with mild to moderate OSA (an AHI of 1–10 events per hour) and mandibular retrognathia (ANB angle ≥ 4.5°). Participants were randomly allocated to four groups: pharmacotherapy, DOT (combined maxillary expansion and mandibular advancement appliance), AT (adenotonsillectomy under general anesthesia), and AT & DOT groups. The primary outcome was the change in apnea–hypopnea index (AHI) from baseline to 7 months post-treatment. Secondary outcomes included assessments of dentofacial development and volumetric changes in the upper airway. Results: Because of the high dropout/loss-to-follow-up rates in the pharmacotherapy and AT plus DOT groups, the final analysis was restricted to the DOT and AT groups, in which the overall dropout/loss-to-follow-up rate was 19.6%. Among the 43 participants allocated to the DOT (8 girls and 15 boys) and AT groups (8 girls and 12 boys), 36 completed the follow-up, the median baseline AHI was 3.7 events/h [IQR, 1.9–4.4]. Per protocol analysis revealed a mean reduction in AHI of 1.6 events/h in the DOT group and 1.3 events/h in the AT group, with no significant difference between the groups (−0.43 [95% CI, −1.48 to 0.61], p = 0.40). DOT significantly promoted sagittal mandibular growth without inducing a vertical clockwise rotation tendency, whereas AT had no significant effect on dentofacial development. Total upper airway volume increased significantly in both groups, with the increase concentrated in different regions of the upper airway depending on the group. Conclusions: In children with mild to moderate OSA and mandibular retrognathia, DOT demonstrated comparable efficacy to AT, which may be attributable to favorable anatomical remodeling of the upper airway. Full article

Obstructive sleep apnea (OSA) affects nearly one billion adults worldwide and involves mechanical upper-airway obstruction alongside metabolic dysfunction, systemic inflammation, and gut–brain axis disruption. Despite the efficacy of continuous positive airway pressure (CPAP), suboptimal long-term adherence highlights the need for complementary pharmacological strategies. This narrative review synthesizes preclinical and clinical evidence on GLP-1-based therapies, encompassing selective GLP-1 receptor agonists and tirzepatide, a dual GIP/GLP-1 receptor agonist, in obesity-associated OSA. Preclinical studies show that GLP-1 receptor activation can reduce visceral adiposity, attenuate pro-inflammatory signaling, improve glucose and lipid metabolism, and modulate hypothalamic appetite circuits. However, the only identified murine study evaluating liraglutide during intermittent hypoxia—an experimental model of one component of OSA rather than the complete disorder—did not reverse hypoxia-induced insulin resistance, indicating that persistent intermittent hypoxia may limit metabolic improvement in that model. Clinically, liraglutide and tirzepatide have reduced the apnea–hypopnea index (AHI) and improved several cardiometabolic outcomes. Numerically larger AHI reductions were reported in the tirzepatide trials, although no head-to-head comparison with selective GLP-1 receptor agonists is available. Tirzepatide is approved by the U.S. Food and Drug Administration for moderate-to-severe OSA in adults with obesity, together with a reduced-calorie diet and increased physical activity, and may be used without concomitant positive airway pressure in eligible patients or as an adjunct to ongoing therapy. The observed respiratory benefits appear to be mediated predominantly by weight loss and related reductions in mechanical and metabolic burden. Evidence supporting additional weight-independent mechanisms remains insufficient, and longer-term mechanistic studies in broader populations are required. Full article

Background/Objectives: Obstructive sleep apnea (OSA) is a sleep condition characterized by intermittent hypoxia, systemic inflammation, and metabolic dysfunction. Contemporary diagnosis criteria depend on polysomnography (PSG), a procedure that is limited by cost and accessibility. Identifying reliable circulating biomarkers may facilitate disease diagnosis and treatment monitoring. Methods: Insulin-like growth factor binding protein-7 (IGFBP-7) has been implicated in pathways relevant to OSA, although its precise role remains elusive. While we previously identified IGFBP-7 as a candidate of interest, in this report, we assessed circulating IGFBP-7 levels in a single-cohort study of 164 participants (124 with OSA, 40 controls) at the Dasman Diabetes Institute. A Type I PSG test was performed in a level 1 sleep laboratory to diagnose sleep apnea. Among the 124 patients with OSA who underwent multilevel sleep surgery (MLS), 67 completed the 3-month postoperative follow-up and were included in the longitudinal analyses. In these participants, we evaluated the apnea–hypopnea index (AHI) at baseline and 3 months after surgery and examined the associations between circulating IGFBP-7 levels, OSA severity indices, and metabolic parameters. Results: Our data revealed a significant increase in IGFBP-7 levels in people with OSA compared to controls (p < 0.001). Importantly, the increase in IGFBP-7 was positively correlated with AHI (r = 0.272, p < 0.001), indicating a potential link with this condition. IGFBP-7 levels declined significantly following MLS (p < 0.001), paralleling improvements in AHI and suggesting responsiveness to therapeutic intervention and a reduced hypoxic burden. IGFBP-4 levels increased significantly in patients with OSA (p = 0.006) but were not correlated with IGFBP-7. The receiver operating characteristic (ROC) analysis identified IGFBP-7 with a cut-off value of 14,003.21 pg/mL as a potential biomarker for OSA, with moderate performance (AUC = 0.722, 95% CI: 0.636–0.808; sensitivity 73%, specificity 84%). Notably, combining IGFBP-7 with IGFBP-4 resulted in a modest improvement (AUC = 0.755). Conclusions: Our data suggest that IGFBP-7 shows a modest association with OSA severity and may have exploratory value as part of a multi-marker or risk-stratification approach. Further large-scale and longitudinal studies are warranted to extensively explore the potential utility of IGFBP-7 within multi-marker approaches. Full article

Background/Objectives: Obstructive sleep apnea (OSA) is a prevalent chronic disorder whose first-line treatment, continuous positive airway pressure (CPAP), is effective only if the patient maintains sufficient adherence. Early predictions of the risk of low adherence would make it possible to personalize follow-up and optimize healthcare resources. The aim of this study was to develop and evaluate a machine-learning-based clinical decision support system to predict CPAP adherence after one year of treatment. Methods: A cohort of 200 patients with OSA from the Sleep-Disordered Breathing Unit of Hospital Álvaro Cunqueiro in Vigo was used. The cohort was split into a training set (n = 160) and an independent test set (n = 40). Two scenarios were defined: Scenario A, with pre-treatment variables, and Scenario B, which also includes early adherence metrics. In each scenario, variables were selected through recursive feature elimination. The selected variables were apnea-hypopnea index (AHI), 3% oxygen desaturation index (ODI3%), chronic obstructive pulmonary disease and neck circumference in Scenario A, and first-month adherence, ODI3% and AHI in Scenario B. Once these subsets were defined, several classifiers were analyzed. Results: Random Forest was the model selected in both scenarios. On the test set, Scenario A reached an area under the curve (AUC) of 0.71 (sensitivity 0.83; specificity 0.45) and Scenario B an AUC of 0.91 (sensitivity 0.90; specificity 0.82). Conclusions: Early prediction of CPAP adherence using machine learning is feasible; incorporating real first-month use markedly improves discriminative ability. The system was integrated into a web prototype as a proof of concept. Given the modest sample size and the absence of external validation, these results should be interpreted as preliminary, corresponding to an exploratory, feasibility study. For future implementation, an extensive clinical validation process will be required, along with the expansion of the database, which will likely contribute to improving the system’s robustness and generalization capacity. Full article

Background/Objectives: Systemic mastocytosis (SM) is a rare clonal mast cell disorder associated with mediator-related symptoms and a broad range of neurocognitive and sleep-related complaints. Fatigue, insomnia, and brain fog are frequently reported in clinical practice, but objective polysomnographic data in this patient population remain limited. As overweight and obesity are established contributors to sleep-disordered breathing, polysomnography (PSG) findings in patients with SM should be interpreted with caution when a control group is not available. This study aimed to characterize sleep architecture, sleep continuity, and sleep-disordered breathing in adult patients with SM who underwent PSG. Methods: This single-center observational study included nine adult patients diagnosed with SM from the Ege University Mastocytosis Database between January 2023 and January 2024. No control group was included. All patients underwent overnight laboratory PSG after discontinuation of antihistamine therapy for at least seven days. Demographic characteristics, SM subtype, baseline serum tryptase levels, Epworth Sleepiness Scale (ESS) scores, and brain fog-like cognitive complaints were recorded. PSG parameters included total sleep time, sleep efficiency, sleep onset latency, wake after sleep onset, rapid eye movement (REM) latency, sleep stage distribution, arousal burden, apnea–hypopnea index (AHI), oxygenation parameters, and periodic limb movements. Results: The study included four women and five men, with a median age of 50 years. Eight patients had a body mass index (BMI) ≥ 25 kg/m², indicating that the cohort was predominantly overweight or obese. The most common SM subtype was indolent SM. The median baseline serum tryptase level was 55.9 ng/mL, and the median ESS score was 9. Only two patients had excessive daytime sleepiness according to ESS > 10, whereas six patients reported brain fog-like complaints. Median sleep efficiency was 91.4%, total sleep time was 344 min, sleep onset latency was 9 min, and wake after sleep onset was 11 min. Median REM latency was 128.5 min. Sleep stage distribution showed median N1, N2, N3, and REM sleep proportions of 3%, 54%, 26%, and 16.7%, respectively. One patient had no observed REM sleep, and two patients had no measurable N3 sleep. The median number of arousals was 55. The median AHI was 8.2 events/hour. Although eight of nine patients met PSG criteria for obstructive sleep apnea (OSA), including five with mild and three with severe disease, this finding should be interpreted in the context of the high prevalence of overweight/obesity in the cohort. All patients with BMI ≥ 25 kg/m² had OSA, whereas the only normal-weight patient did not. Conclusions: In this single- center observational study, PSG demonstrated frequent sleep-disordered breathing, REM-related changes, and variable arousal burden in patients with SM; however, these findings cannot be separated from the predominance of overweight/obesity and the absence of a control group. Brain fog-like complaints were common, although excessive daytime sleepiness was present in only a minority of patients. Because most patients were overweight or obese and no control group was included, these findings cannot be attributed directly to SM. However, the results suggest that objective sleep assessment may be useful in selected patients with SM, particularly when fatigue, non-restorative sleep, or cognitive complaints are present. Larger controlled studies with BMI-matched groups are needed to clarify the relationship between SM, mast cell mediator activity, and sleep abnormalities. Full article

Background/Objectives: Human breathing occurs through either the nasal or the oral route. Nasal breathing is the physiological mode of ventilation and contributes to nitric oxide delivery, upper-airway regulation, and efficient pulmonary gas exchange. In contrast, chronic oral breathing has been associated with upper-airway dysfunction, impaired nocturnal oxygenation, and chronic intermittent hypoxia, conditions increasingly associated with cardiovascular, metabolic, respiratory, neurocognitive, and oncological diseases. To determine whether adults with cancer exhibit structural and functional craniofacial characteristics associated with oral breathing patterns and altered nocturnal oxygenation. Methods: We conducted an exploratory case–control study including adults with cancer and matched controls. Participants underwent a standardized multidimensional airway assessment comprising symptom evaluation using the STOP-BANG questionnaire, structured clinical examination of upper-airway and orofacial characteristics, craniofacial assessment, cone-beam computed tomography (CBCT), and home respiratory polygraphy to characterize upper-airway phenotype and nocturnal oxygenation patterns. Results: Adults with cancer exhibited impaired nocturnal oxygenation despite comparable apnea–hypopnea index values. They also exhibited a higher prevalence of structural and functional upper-airway abnormalities, including restricted tongue mobility, anterior open bite, and reduced maxillary transverse dimensions. Conclusions: This exploratory study identifies a distinct upper-airway phenotype in adults with cancer, characterized by craniofacial and functional features associated with impaired nocturnal oxygenation. These findings suggest that upper-airway anatomy and nocturnal oxygenation may contribute to systemic disease vulnerability and warrant further investigation. Full article

Pediatric sleep-disordered breathing (SDB) is underdiagnosed despite its associations with adverse neurobehavioral, psychosocial, and cardiometabolic outcomes. Pediatric dental providers routinely evaluate craniofacial growth and maintain longitudinal contact with children, yet practical approaches for integrating SDB risk assessment into dental settings remain limited. This protocol describes a prospective, cross-sectional observational study that will enroll 60 school-aged children aged 8–13 years from a university-based pediatric dental clinic and classify them as low-risk or high-risk for SDB using the Pediatric Sleep Questionnaire (PSQ; threshold ≥ 0.33). The primary aim is to examine associations between PSQ-based risk classification and objective physiologic sleep parameters, including the Apnea–Hypopnea Index, Respiratory Disturbance Index, Sleep Apnea Indicator, and Sleep Quality Index, obtained from a U.S. Food and Drug Administration-cleared wearable home sleep monitor—SleepImage Ring (MyCardio LLC, Denver, CO, USA)—worn for a minimum of three consecutive nights. Secondary aims will evaluate associations between SDB risk classification and body mass index, Mallampati score, Brodsky tonsillar grade, and psychosocial functioning (anxiety, depression, perceived stress, and daytime sleepiness). Exploratory craniofacial analyses will be conducted among participants with clinically available lateral cephalometric radiographs. This protocol could position pediatric dental visits as an accessible touchpoint for early identification of children with unrecognized SDB and inform pathways for timely referral. Protocol Version: 1.4, dated 13 May 2026. Trial Registration: ClinicalTrials.gov NCT07581938. Full article

Background: This study evaluated the use of circulation time (Tcirc) calculated from polysomnogram (PSG) with pulse oximetry to identify poor cardiac function with low left ventricular ejection fraction (EF). Methods: Subjects over 18 years of age with sleep apnea (apnea-hypopnea index (AHI) > 5/h diagnosed by PSG who had transthoracic echocardiography (TTE) within 1 year of PSG were included in this retrospective study. Tcirc of each sleep stage (N2, N3, and REM) were measured and averaged and EF was recorded. Statistical analysis was carried out using the Wilcoxon rank sum test, logistic regression and Youden index. Results: There were 89 subjects who met the inclusion criteria, 14 with EF ≤ 45% (Group A) and 75 with EF ≥ 50% (Group B). The normal Tcirc is <20 s, but Group A subjects had a prolonged overall Tcirc with a median time of 27.8 s (range 14.1–39.6 s), compared to Group B subjects with a median Tcirc of 23.5 s (range 14.3–37.6 s), p = 0.311. The optimal cut-point for overall sleep Tcirc with moderate discrimination (AUC = 0.6) was 28.6 s. Those with total sleep Tcirc ≥ 28.6 s were 2.5× more likely to have low EF with OR = 2.56 (95% CI, 0.55–11.16). Conclusions: In sleep apnea patients, total sleep Tcirc > 28.6 s is associated with low ejection fraction with specificity = 0.78. Full article

Background: Cluster headache (CH) and obstructive sleep apnea (OSA) are both associated with elevated cardiovascular risk and unhealthy lifestyle factors, including smoking and alcohol use. This study investigated whether the conventional STOP-Bang questionnaire or a modified screening approach incorporating CH-specific clinical features is more useful for identifying treatment-relevant OSA. Methods: We retrospectively analyzed 52 patients with CH who underwent polysomnography (PSG) between January 2020 and December 2025. An apnea–hypopnea index (AHI) of at least 10 events/hour was defined as treatment-relevant OSA. We assessed whether incorporating age at CH onset and the circadian and/or seasonal rhythmicity of CH attacks into the STOP-Bang questionnaire improved screening performance. Results: Of 52 patients, 41 (78.8%) were diagnosed with OSA (AHI ≥ 5) and 25 (48.1%) had treatment-relevant OSA. Patients with treatment-relevant OSA were predominantly male and had a higher median age, body mass index, and age at CH onset. A modified model incorporating CH onset at or after age 30 showed modest improvement than conventional STOP-Bang. At a cut-off point of ≥3, the modified model demonstrated a numerically higher area under the curve (0.804 vs. 0.767) and greater sensitivity (84.0% vs. 76.0%; DeLong p = 0.125), with low specificity (48.1% vs. 55.6%). At a cut-off point of ≥4, the specificity increased to 77.8%. The addition of other clinical characteristics of CH did not further improve the performance. Conclusions: Incorporating CH onset age into the STOP-Bang modestly improved screening for treatment-relevant OSA in CH patients, representing a practical screening refinement warranting external validation. Full article