Objective Rapid eye movement (REM)-related sleep disordered breathing (SDB) is an entity in which the cessation or reduction of breathing occurs primarily during the REM period. Most studies have shown that REM-related SDB more frequently affects women, younger people and patients with mild or moderate SDB. The aim of this study was to prospectively investigate the prevalence and features of REM-related SDB in Japanese subjects compared with the findings of previous reports. Methods A total of 468 patients were evaluated in this study. The diagnosis of SDB was established using polysomnographic monitoring. The patient variables included age, gender, body characteristics, comorbidities, etc. Results REM-related SDB was more prevalent in women than non-REM-related SDB (male ratio; 66.3% vs. 79.5%, p=0.03). Moreover, the patients with REM-related SDB had lower body mass indexes (25.9±6.9 vs. 28.5±7.7; p=0.003), arousal indexes (31.8±10.7 vs. 61.0±29.1; p<0.001), apnea hypopnea indexes (15.0± 8.0 vs. 54.9±35.9) and glycosylated hemoglobin (HbA1c) levels (5.5±0.9 vs. 5.9±2.6; p=0.02) than the patients with non-REM-related SDB. However, the overall and female gender prevalence of REM-related SDB among the Japanese subjects was lower than that shown in previous reports. The finding that REM-related SDB was not prevalent in younger individuals or severely obese patients was not consistent with the results of previous studies. Conclusion The present findings suggest that REM-related SDB may have different clinical characteristics in the Japanese population than that observed in previous reports.Key words: sleep apnea syndrome, rapid eye movement (REM), body mass index (BMI), polysomnography (PSG), sleep disordered breathing (SDB), glycosylated hemoglobin (HbA1c)

A commentary on this article appears in this issue on page 301.

Objective Osteoporosis, which is now recognized as a major comorbidity of chronic obstructive pulmonary disease (COPD), must be diagnosed by appropriate methods. The aims of this study were to clarify the relationships between bone mineral density (BMD) and COPD-related clinical variables and to explore the association of BMD with the updated Global Initiative for Chronic Obstructive Lung Disease (GOLD) classification in men. Methods We enrolled 50 Japanese men with clinically stable COPD who underwent dual-energy X-ray absorptiometry (DEXA), pulmonary function testing, and computerized tomography (CT) and who had completed a questionnaire (COPD assessment test [CAT]). We determined the association between the T-score and other tested parameters and compared the BMD of patients in each GOLD category. Results Twenty-three of the 50 patients (46.0%) were diagnosed with osteopenia, and 7 (14.0%) were diagnosed with osteoporosis. The BMD findings were significantly correlated with the CAT score, forced expiratory volume in 1 second percentage predicted (FEV1% predicted), low attenuation volume percentage (LAV%), and percentage of cross-sectional area of small pulmonary vessels (%CSA) on CT images. Notably, the median T-score of the GOLD category D participants was significantly lower than that of the participants in each of the other categories (A [-0.98], B [-1.06], C [-1.05], and D [-2.19], p<0.05). Conclusion Reduced BMD was associated with airflow limitation, extent of radiographic findings, and a poor quality of life (QOL) in patients with COPD. The BMD of GOLD category D patients was the lowest of all of the patients evaluated, and category D patients may benefit from active intervention for osteoporosis.

BackgroundWe aimed to study whether pulmonary arterial distensibility (PAD) correlates with hemodynamic parameters in chronic thromboembolic pulmonary hypertension (CTEPH) using electrocardiogram (ECG)-gated 320-slice multidetector computed tomography (MDCT).Methods and FindingsECG-gated 320-slice MDCT and right heart catheterization (RHC) was performed in 53 subjects (60.6±11.4 years old; 37 females) with CTEPH. We retrospectively measured the minimum and maximum values of the cross sectional area (CSA) of the main pulmonary artery (mainPA), right pulmonary artery (rtPA), and left pulmonary artery (ltPA) during one heartbeat. PAD was calculated using the following formula: PAD = [(CSAmaximum−CSAminimum)/CSAmaximum]×100(%). The correlation between hemodynamic parameters and PAD was assessed. Mean pulmonary arterial pressure (mPAP) and pulmonary vascular resistance (PVR) were 40.8±8.7 mmHg and 8.3±3.0 wood units, respectively. PAD values were as follows: mainPA (14.0±5.0%), rtPA (12.8±5.6%), and ltPA (9.7±4.6%). Good correlations existed between mainPAD, with mPAP (r = −0.594, p<0.001) and PVR (r = −0.659, p<0.001). The correlation coefficients between rtPAD and ltPAD with pulmonary hemodynamics were all lower or equal than for mainPAD.ConclusionsPAD measured using ECG-gated 320-slice MDCT correlates with pulmonary hemodynamics in subjects with CTEPH. The mainPA is suitable for PAD measurement.

Study Objectives: Although moderate to severe obstructive sleep apnea (OSA) is an independent risk factor for severe arteriosclerotic diseases such as cardiovascular disease (CVD) and stroke, the development of atherosclerosis-related diseases cannot yet be predicted in patients with OSA. In a pilot study, we identified autoantibodies against the coatomer protein complex, subunit epsilon [circulating anti-coatomer protein complex subunit epsilon autoantibody (COPE-Ab)], a cytosolic complex that mediates protein transport in the Golgi compartment, as a potential novel biomarker of atherosclerosis. This study aimed to evaluate whether COPE-Ab levels had an association with cardiovascular and cerebrovascular events in patients with OSA. Methods: Eighty-two adult patients with a diagnosis of OSA via polysomnography and 64 healthy donors were studied. Serum COPE-Ab levels were measured using an amplified luminescence proximity homogeneous assay. Then, clinical factors related to atherosclerosis were evaluated with respect to COPE-Ab levels. Results: Significant differences in COPE-Ab levels were observed in terms of OSA severity. COPE-Ab levels were significantly higher in patients with OSA and also CVD and/or stroke, hypertension, and a high body mass index. Univariate and multivariate logistic regression analyses of patients with OSA identified elevated COPE-Ab level as a significant predictor of CVD and/or stroke. Conclusions: An elevated COPE-Ab level may be a potential predictor of the risks of cardiovascular and cerebrovascular events in patients with OSA. Therefore, patients with higher COPE-Ab levels may require more careful and intensive treatment. Commentary: A commentary on this article appears in this issue on page 361.