Relationship between sleep disordered breathing and heart rate turbulence in non-obese subjects.

Heart rate turbulence (HRT) is regarded as a parameter of cardiac autonomic dysfunction. Several studies have suggested that patients with sleep disordered breathing (SDB) have an impaired HRT, which play a role in the relationship between SDB and risk of cardiovascular morbidity and mortality. However, the impact of SDB on HRT independent from obesity is still debatable. Data of eligible subjects who underwent sleep test and 24 h Holter electrocardiogram (ECG) recording from 2009-2012 were analyzed. HRT parameters, turbulence onset (TO), and turbulence slope (TS) in the 24 h recording, while awakening, and sleeping (TO-24 h, TO-awake, TO-sleep, TS-24 h, TS-awake, and TS-sleep, respectively) were compared across subjects with no-to-mild, moderate, and severe SDB. Univariable and multivariable regression analyses including TO or TS as a dependent variable were performed. Data from 41 subjects were evaluated. Compared with the no-to-mild and moderate SDB groups, in the severe SDB group, the TO-24 h and TO-awake were significantly greater, and the TS-24 h, TS-awake, and TS-sleep were significantly lower. In multivariable analyses, the apnea-hypopnea index (AHI) was correlated directly with TO-24 h (coefficient, 0.36; P = 0.03) and TO-awake (coefficient, 0.40; P = 0.01). SDB severity, as represented by AHI, is related to HRT impairments in non-obese subjects. SDB, independent from obesity, may affect cardiac autonomic dysfunction.

Clinical utility of a type 4 portable device for in-home screening of sleep disordered breathing.

BACKGROUND: Portable monitoring devices have been developed for in-home screening and to aid in the diagnosis of sleep disordered breathing (SDB) while increasing accessibility and reducing costs. Although there are many different devices available in the market, most have not undergone rigorous validation. Therefore, although such devices are promising, more research on their clinical utility is necessary. The purpose of this study was to assess the clinical utility of a type 4 home sleep apnea test (HSAT) as an in-home screening for SDB. METHODS: We investigated consecutive subjects who underwent in-laboratory overnight polysomnography following in-home screening using HSAT. We evaluated the correlation between apnea-hypopnea index (AHI) by in-laboratory overnight polysomnography and by HSAT and evaluated the sensitivity and specificity for AHI ≥5 and AHI ≥30 by the receiver operating characteristic (ROC) analysis. RESULTS: Finally, data of 387 participants (86.8% men, mean age 55.3±13.3 years and body mass index 25.1±4.1 kg/m2) were assessed. In all patients, AHI by HSAT correlated significantly with AHI by polysomnography (r=0.670, P<0.001). The area under curves of ROC for AHI ≥5 and AHI ≥30 were 0.854±0.029 and 0.841±0.022, respectively. The best cut-off of AHI by HSAT for detecting AHI by polysomnography ≥5 was 10.3 events/h (sensitivity, 82.8%; and specificity, 76.0%), and AHI by HSAT for detecting AHI by polysomnography ≥30 was 24.5 events/h (sensitivity, 75.8%; and specificity, 80.4%). CONCLUSIONS: This type 4 HSAT may have potential as a screening tool for SDB and thus have sufficient clinical utility.

Relationship between sleep disordered breathing and diabetic retinopathy: Analysis of 136 patients with diabetes.

AIMS: Sleep disordered breathing (SDB) is associated with poor glycemic control. However, whether SDB contributes to diabetic microangiopathies, especially diabetic retinopathy (DR), is unknown. The aim of this study was to assess the relationship between SDB and DR. METHODS: Between January 2010 and November 2012, 136 patients underwent a sleep test and were divided into two groups according to the presence or absence of DR. Sleep test results and known risk factors for DR were compared between groups. Optic fundi were examined using indirect ophthalmoscope or retinal photographs and diagnosed by experienced ophthalmologists. Multivariate stepwise (backward) logistic regression analysis was performed to assess factors associated with DR. RESULTS: Ninety-nine patients without DR (NDR) and 37 patients with DR were assessed. Patients in the DR group had significantly longer duration of diabetes, were more likely to have hypertension and cardiovascular disease (CVD), and were more likely to be taking angiotensin converting enzyme inhibitors or angiotensin receptor blockers (p=0.000 for each). In the multivariate backward logistic regression analysis, minimum SO2 (odds ratio [OR], 0.89; p=0.001), HbA1c (OR, 1.40; p=0.021), duration of diabetes (OR, 1.23; p<0.001), and history of CVD (OR, 8.96; p=0.008) remained significant. CONCLUSIONS: Minimum SO2 values were associated with DR independent from glycemic control level, duration of diabetes, and history of CVD. This finding suggests that SDB may contribute to the development of DR not through frequency, but due to the degree of intermittent hypoxia.