Postprandial glucose and HbA1c are associated with severity of obstructive sleep apnoea in non-diabetic obese subjects.

INTRODUCTION: Obstructive sleep apnoea (OSA) is an underdiagnosed condition frequently associated with glycaemic control impairment in patients with type 2 diabetes. AIM: To assess the relationship between glycometabolic parameters and OSA in obese non-diabetic subjects. METHODS: Ninety consecutive subjects (mean age 44.9 ± 12 years, mean BMI 42.1 ± 9 kg/m2) underwent polysomnography and a 2-h oral glucose tolerance test (OGTT). RESULTS: OSA was identified in 75% of subjects, with a higher prevalence of males compared to the group of subjects without OSA (62% vs 32%, p = 0.02). Patients with OSA had comparable BMI (42.8 kg/m2 vs 39.4 kg/m2), a higher average HbA1c (5.8% vs 5.4%, p < 0.001), plasma glucose at 120 min during OGTT (2 h-PG; 123 mg/dl vs 97 mg/dl, p = 0.009) and diastolic blood pressure (81.1 mmHg vs 76.2 mmHg, p = 0.046) than obese subjects without OSA. HbA1c and 2 h-PG were found to be correlated with the apnoea-hypopnoea index (AHI; r = 0.35 and r = 0.42, respectively) and with percent of sleep time with oxyhaemoglobin saturation < 90% (ST90; r = 0.44 and r = 0.39, respectively). Further, in a linear regression model, ST90 and AHI were found to be the main determinants of 2 h-PG (ß = 0.81, p < 0.01 and ß = 0.75, p = 0.02, respectively) after controlling for age, sex, waist circumference, physical activity, and C-reactive protein. Similarly, ST90 and AHI persisted as independent determinants of HbA1c (ß = 0.01, p = 0.01 and ß = 0.01, p = 0.01, respectively). CONCLUSION: Beyond the traditional clinical parameters, the presence of a normal-high value of 2 h-PG and HbA1c should raise suspicion of the presence of OSA in obese subjects.

Vitamin D deficiency as a predictor of poor prognosis in patients with acute respiratory failure due to COVID-19.

PURPOSE: Hypovitaminosis D is a highly spread condition correlated with increased risk of respiratory tract infections. Nowadays, the world is in the grip of the Coronavirus disease 19 (COVID 19) pandemic. In these patients, cytokine storm is associated with disease severity. In consideration of the role of vitamin D in the immune system, aim of this study was to analyse vitamin D levels in patients with acute respiratory failure due to COVID-19 and to assess any correlations with disease severity and prognosis. METHODS: In this retrospective, observational study, we analysed demographic, clinical and laboratory data of 42 patients with acute respiratory failure due to COVID-19, treated in Respiratory Intermediate Care Unit (RICU) of the Policlinic of Bari from March, 11 to April 30, 2020. RESULTS: Eighty one percent of patients had hypovitaminosis D. Based on vitamin D levels, the population was stratified into four groups: no hypovitaminosis D, insufficiency, moderate deficiency, and severe deficiency. No differences regarding demographic and clinical characteristics were found. A survival analysis highlighted that, after 10 days of hospitalization, severe vitamin D deficiency patients had a 50% mortality probability, while those with vitamin D ≥ 10 ng/mL had a 5% mortality risk (p = 0.019). CONCLUSIONS: High prevalence of hypovitaminosis D was found in COVID-19 patients with acute respiratory failure, treated in a RICU. Patients with severe vitamin D deficiency had a significantly higher mortality risk. Severe vitamin D deficiency may be a marker of poor prognosis in these patients, suggesting that adjunctive treatment might improve disease outcomes.

Influence of circadian rhythm on exhaled breath profiling by electronic nose.

Electronic noses (e-noses) are a cheap and easy method for exhaled Volatile Organic Compound (VOC)-analysis which has shown its potential in several diseases. Before obtaining a full validation of these instruments in clinical settings, a number of methodological issues still have to be established. We aimed to investigate a potential influence of circadian variation on VOC-profile analyzed by an e-nose in healthy subjects. We enrolled 22 adults free of any known diseases. A sequence of exhaled breath samplings were performed on all participants at predetermined hours (7am, 12pm, 17pm, 23pm) and analyzed by an e-nose (Cyranose 320). According to Principal Component Analysis, significant circadian variations of the exhaled VOC-profile were shown for Principal Component (PC) 1 and 3. In detail, PC1 and PC3 values were significantly higher in the morning compared to the afternoon and evening (for all parameters p less than 0.05). Successive Linear Discriminant analysis confirmed the findings above. The daily variations in VOCs-profile, with the peak in the morning, could be relevant for future clinical applications, especially in the choice of optimal time for sampling patients.

Standardization procedure for the nasal nitric oxide measurement method using Niox MINO® and the tidal-breathing technique with velum-closure.

Nitric oxide (NO) is a molecule that performs many functions in the human body. The entire respiratory tract can produce NO, but the highest production occurs in the upper respiratory tract, in the paranasal sinuses in particular. The aim of the present study was to assess a new nasal NO (nNO) measurement method using the Niox MINO Nasal® device (Aerocrine AB, Solna, Sweden) and a special procedure, in order to compare the nNO values obtained in 32 healthy subjects with the values found in the international literature. The measured normal nNO values were equal to 426.76±143.27 ppb, with a 95% confidence interval [160.22-733.30]. Males had an average nNO value equal to 446.76±133.63 [178.64 – 714.02], whereas in females the average value was 403.80±154.90 [94.00-713.60]. This study allows us to confirm that we have been able to establish the normal range of nitric oxide quantity produced in the nasal/sinus cavities of healthy individuals using the Niox MINO Nasal® device and tidal-breathing with velum-closure manoeuvre.