Elevated obstructive sleep apnoea risk score is associated with poor healing of diabetic foot ulcers: a prospective cohort study.

AIMS: To assess the prevalence of risk factors for obstructive sleep apnoea in people with diabetic foot ulcers and to determine whether this risk predicts diabetic foot ulcer healing. METHODS: We studied 94 consecutive people (69% men) with diabetic foot ulcers (Type 2 diabetes, n=66, Type 1 diabetes, n=28) attending a university hospital foot unit. All participants were screened for obstructive sleep apnoea using the STOP-BANG questionnaire, with a score ≥4 identifying high risk of obstructive sleep apnoea. The primary outcome was poor diabetic foot ulcer healing, defined as diabetic foot ulcer recurrence (diabetic foot ulcers which healed and re-ulcerated in same anatomical position) and/or diabetic foot ulcer persistence (no evidence of healing on clinical examination). All participants were evaluated at 12 months. RESULTS: Of the 94 participants, 60 (64%) had a STOP-BANG score ≥4. Over 12 months, 27 participants with a score ≥4 had poor diabetic foot ulcer healing as compared to seven with a score <4 (45% vs 20.5%; P=0.025). A STOP-BANG score ≥4 significantly increased the relative risk of poor healing more than twofold, independently of other risk factors in multivariable analyses. CONCLUSIONS: There is a high prevalence of features and risk of obstructive sleep apnoea in people with diabetic foot ulcers. A STOP-BANG score ≥4 predicts poor diabetic foot ulcer healing. Obstructive sleep apnoea may be a potential, modifiable risk factor/treatment target to improve diabetic foot ulcer outcomes.

Characterisation of sleep disturbances in postural orthostatic tachycardia syndrome: a polysomnography-based study.

BACKGROUND AND AIM: Postural orthostatic tachycardia syndrome (PoTS) has been frequently associated with sleep disturbances but objective sleep data are lacking. In addition, although regional autonomic denervation has been described, less is known about autonomic nervous activity overnight in these patients. PATIENTS/METHODS: A full polysomnography and heart rate variability were performed on 37 patients diagnosed with PoTS . In addition, a multiple sleep latency test (MSLT) was conducted on a subgroup of patients with excessive daytime sleepiness. RESULTS: The polysomnographic data did not show major pathological findings except the percentage spent in rapid eye movement (REM) sleep which was slightly reduced at 18.4%. The MSLT did not confirm excessive daytime sleepiness as median mean sleep latency was 14.4 min (11.8-17.5). When comparing patients with and without subjective daytime sleepiness, it was found that the latter had a reduced parasympathetic activation at night as expressed by the average high frequency [6936.5 ms(2) (6028.2-8675.5) vs. 4689.5 (3922.7-7685.2) p < 0.05]. CONCLUSION: Patients with PoTS do not exhibit polysomnographic findings consistent with relevant sleep pathologies nor objective daytime sleepiness. Subjective daytime sleepiness is associated with enhanced activation of the parasympathetic nervous system.

The impact of obstructive sleep apnea syndrome severity on physical performance and mental health. The use of SF-36 questionnaire in sleep apnea.

OBJECTIVES: Obstructive sleep apnea syndrome (OSAS) is a common disorder defined by repeated episodes of airflow cessation (apneas)leading to arterial hypoxemia and sleep disruption. OSAS has been associated with increased morbidity, mortality and diminished quality of life so far. This cross-sectional study aimed to assess the impact of OSAS on patients' Quality of Life, as measured by the Medical Outcomes Study Short Form-36 (SF-36). PATIENTS AND METHODS: Two hundred and forty five subjects referred to the sleep laboratory and underwent full polysomnography overnight. Prior to sleep study onset, we registered height and weight, medical history, smoking habit, drug consumption. Afterwards, each patient completed the SF-36. Eighty subjects not diagnosed with sleep apnea [apnea hypopnea index (AHI < 5)] were excluded. Therefore, 165 subjects (121 male and 44 female) remained. RESULTS AND CONCLUSIONS: Statistical analysis revealed that in patients with respiratory disturbance index (RDI) ≥ 15, (n = 115), RDI was independently associated with lower performance in role limitations due to physical problems (p = 0.005). Additionally, RDI was the only factor associated with decreased vitality (p = 0.014) and mental health scores (p = 0.047). In the same patient subgroup, body mass index (BMI) and age were associated with poorer scores in physical functioning (p < 0.001 and p = 0.003, respectively). BMI was an independent clinical predictor of worse scores in bodily pain (p = 0.006) general health (p = 0.006), social functioning (p = 0.025) and role limitations due to emotional problems (p = 0.004).

Association of ET-1 gene polymorphisms with COPD phenotypes in a Caucasian population.

BACKGROUND AND AIM: The phenotypic expression of COPD consists of pulmonary emphysema and chronic bronchitis. An imprecise phenotypic definition may result in inconsistencies among genetic studies regarding COPD pathogenesis. Endothelin-1 gene polymorphisms have been linked to increased susceptibility of COPD development. The present study examined the involvement of +138 insA/delA and G198T ET-1 polymorphisms with emphysematous and bronchitic COPD phenotypes. METHODS: In order to narrow down the phenotypic choices to either COPD-associated pulmonary emphysema or chronic bronchitis, a DLCO < 60% predicted threshold was chosen as an indicator of severe emphysema. 116 COPD smokers and 74 non-related, non-COPD smokers were evaluated. RESULTS: Statistical analysis showed that the 4A allele of the +138insA/delA SNP and the 4A:T haplotype were associated predominantly with a chronic bronchitis phenotype, whereas the TT genotype of the G198T SNP was found to be protective from emphysema development. CONCLUSIONS: The presence of both the 4A and T allele seems to modify the final expression of COPD towards a chronic bronchitis phenotype, since the G:3A haplotype was associated with a predominantly emphysematous phenotype in our study.

Endothelin-1 polymorphisms involved in impaired exercise tolerance in COPD patients. A pilot study.

INTRODUCTION: Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality worldwide that may lead to impaired exercise tolerance. In this study we exhibit the relationship between two endothelin-1 (+134 3A/4A and G198T) SNPs involved in COPD and their association to impaired exercise tolerance. MATERIALS AND METHODS: The study population consisted of 22 COPD smokers and 32 smoking controls which underwent pulmonary function tests to assess forced expiratory volume for 1 second (FEV1), forced vital capacity (FVC), as well as cardiopulmonary exercise testing. Single nucleotide polymorphism were isolated using Real-Time PCR. RESULTS: The distribution of both genotypes (3A3A, 3A4A, 4A4A for the +134 3A/4A and GG, GT, TT for the G198T) did not different among patients and non-COPD smoking controls. Multivariate analysis showed that the 3A4A and GG genotypes in the COPD group were independently associated with better V'O2max values (Odd's Ratio (OR) = 12.5, 95% CI = -0.85-25.1, p = 0.049, and OR = 6.1, 95% CI = 0.83-11.4, p = 0.026, respectively). On the contrary analogous analysis in the non-COPD control group, showed that the 3A3A genotype was independently associated with increased V'O2/pulse (OR = 51.5, 95% CI = 17.2-85.7, p = 0.005) and the 3A4A genotype with increased DVE/DVCO2 value (OR = 3.8, 95% CI = -0.27-7.9, p = 0.054). DISCUSSION: Our results show that endothelin-1 gene is implicated in exercise performance in COPD patients and might play a role in adaptation of the cardiopulmonary system to exercise.

The role of Endothelin-1 in obstructive sleep apnea syndrome and pulmonary arterial hypertension: pathogenesis and Endothelin-1 antagonists.

Obstructive Sleep Apnea Syndrome (OSAS) is a recognized risk factor for cardiovascular disorders and in some cases is complicated with Pulmonary Arterial Hypertension (PAH), as the endothelium is affected. Recent studies provide strong evidence for endothelial dysfunction in obstructive sleep apnea. The resultant vasoconstriction, abnormal cell proliferation and hyper-coagulability may lead to the initiation or progression of atherosclerotic cardiovascular and cerebrovascular disorders, which are frequently encountered in OSA patients. While the currently available therapies for OSAS, such as Continuous Positive Airway Pressure therapy (CPAP therapy), improve endothelial dysfunction, they are not well-tolerated by patients. CPAP therapy can reduce nocturnal hypoxemias and decrease noradrenaline circulating levels, but does not affect ET-1 plasma levels. Potent and selective Endothelin-1 receptor antagonists have been developed and have shown promising results in the treatment of cardiovascular diseases such as pulmonary arterial hypertension, acute and chronic heart failure, hypertension, renal failure, and atherosclerosis. However, results are often contrasting and complicated because of the tissue-specific vasoconstrictor actions of Endothelin-B receptors and the fact that endothelin is an autocrine and paracrine factor whose activity is difficult to measure in vivo.

Environmental noise-annoyance in Patras, Greece.

Noise pollution in most European and mainly Greek towns, is a major environmental problem. The annoyance caused by environmental noise is great and the use of a reliable descriptor of noise is important. This paper attempts to evaluate the noise fluctuations at an observation point by introducing a probabilistic model for the system environment-noise.The proposed model considers environmental noise as a stochastic signal neglecting the identity of noise sources as well as all other physical factors of the system. Regression methods were used to fit fluctuating noise levels to a trigonometric series. The use of "power spectrum" linearizes the problem and simplifies the method of regression in searching for the best model. A correcting term of L dn is proposed and the use of the model makes the calculation of the above mentioned term simple.