Clinical features and predictors of obesity hypoventilation syndrome among patients with obstructive sleep apnea

Background Patients with obesity hypoventilation syndrome (OHS) have increased risk of cardiometabolic complications and higher mortality rate than obstructive sleep apnea (OSA) or eucapnic obese patients. So, understanding the clinical features and predictors of OHS is essential for early diagnosis. Aim of work To study the clinical features, predictors, and percentage of OHS among patients with OSA. Patients and methods Two groups were included OSAOHS (34 patients, 42.5%) and pure OSA (46 patients, 57.5%) subjected to history taking, examination, body measurement, fasting blood sugar and postprandial blood sugar, lipid profile, arterial blood gases (ABGs), and polysomnography (PSG). Results OSA+OHS patients had higher waist circumference (P=0.020), lower PO2, O-2 saturation%, higher PCO2 with higher bicarbonate in ABGs (P<0.001), higher desaturation index (P=0.015), lower minimal O-2 saturation%, lower average O-2 saturation%, and higher SpO(2) less than 90% (P<0.001) in PSG than pure OSA. Cut off value of ABGs HCO3=27mmol/l (sensitivity=100%, specificity=100%, and P<0.001), PO2 less than 66 mmHg (sensitivity=85.3%, specificity=87%), O-2 saturation % less than 91 (sensitivity=82.4%, specificity=97.8), for PSG the cut off value of SpO(2) less than 90%=51% (sensitivity=88.2%, specificity=91.3%), minimal O-2 saturation% less than 61 (sensitivity=64.7%, specificity=89.1%), average O-2 saturation% less than 88 (sensitivity=88.2%, specificity=93.5%) were satisfactory to diagnose OHS. Conclusion Bicarbonate level, oxygen saturation values in ABGs and PSG were predictors of OHS among OSA patients.