Prevalence and predictors of obesity hypoventilation syndrome in an Indian cohort with obstructive sleep apnea.

Obesity hypoventilation syndrome (OHS) is a comorbidity in patients with Obstructive sleep apnea (OSA). It has a significant impact on the treatment and outcomes. There is paucity of data on the prevalence of OHS and its associated factors. Our objective was to estimate this for our Indian cohort. This is a retrospective study on consecutive patients who underwent a sleep study for suspicion of OSA from January 2022 to December 2022. Details of these patients were extracted from the electronic medical records, and the sleep studies were analysed. The prevalence of OHS was calculated. Multiple logistic regression analysis was performed to ascertain the independent OHS predictors. In an Indian patient population comprising predominantly southern and eastern Indian residents, 674 who met the specified criteria were included. Their mean age was 51.7 (SD 12.5), 426 (63.2%) were males, and 51.3% were obese. The prevalence of OHS was 5.8%. Only two patients without OSA had OHS. For the BMI ranges 30-40, 40-50, and > 50 kg/m, the prevalence of OHS was 9%, 13%, and 20%, respectively. Multivariate logistic regression analysis found that female gender (OR = 4.1), BMI ≥ 35 kg/m (OR = 3.2), and orthopnoea (OR = 4.8) were independently associated with OHS. Hypothyroidism (OR = 2.2) showed a significant association only in the univariate analysis. In a cohort of Indian patients referred for a sleep study, the prevalence of OHS is low. Increased BMI, female gender and a history of orthopnea were independent predictors of OHS.