Obesity Hypoventilation Syndrome (OHS) Prevalence and Predictors In patients With ‎Obstructive Sleep Apnea (OSA)‎

Abstract

Patients with obesity hypoventilation syndrome (OHS) suffer from lower quality ‎of life, increased healthcare expenses, ‎and a ‎higher mortality rate compared to eucapnic patients with obstructive sleep ‎apnea ‎‎(OSA). ‎

Despite significant morbidity and mortality rates associated with OHS, it is ‎often ‎unrecognized, and treatment is frequently delayed. The objective of ‎this ‎observational study was to determine the prevalence of OHS in patients with ‎OSA ‎seen at the Sleep Disorders Clinic in Al-Assad University hospital Damascus, ‎Syria. ‎Secondly‎, ‎to ‏‎ identify independent clinical predictors that should prompt ‎clinicians to measure ‎arterial blood gases in order to determine the prevalence of ‎OHS in patients with OSA. Lastly, to identify the presence of comorbidities in ‎patients suffering ‎from OSA, overlap syndrome (OS) (the coexistence of OSA and chronic obstructive pulmonary disease (COPD)), OHS and the differences in ‎these groups of ‎patients.‎

179 patients were collected from the sleep ‎disorders ‎laboratory between September 2018 and September 2020 for suspicion of ‎OSA.

Among these patients 47% were diagnosed with OSA, 17.3% with OHS and ‎‎12.3% ‎with OS. Sleep disordered breathing syndromes were found more ‎prevalent in male (62%).

This study showed that 62.2% of patients had hypertension, as the most ‎prevalent ‎comorbidity associated with sleep disordered breathing syndromes, ‎‎26.3% had ‎DM II, and 13.3% had ischemic heart disease (IHD).‎

When comparing the three syndromes, patients with OHS had the highest ‎BMI ‎‎(mean 43.15 kg/m2), The deepest oxygen desaturation during the sleep study ‎‎(75.8%) and ‎the lowest baseline oxygen saturation was (83%). ‎

The study showed several clinical predictors that indicate the presence of ‎OHS ‎among OSA. These predictors are serum bicarbonate (a good predictor with ‎more than 70% ‎sensitivity and specificity, and a negative predictive value of 93.7%), and baseline oxygen saturation (a fair ‎predictor).‎

In conclusion, the coexistence of OHS and OSA raises the prevalence ‎of ‎comorbidities. The clinical approach and the management of these ‎syndromes are different, highlighting the importance of early diagnosis. There is a ‎lack of studies associated with these syndromes in Syria, therefore it is expected ‎that this study will improve the quality of life of patients and decrease the ‎mortality rate.