Correlation of severity of obstructive sleep apnea, pulmonary function and obesity

Introduction: Obesity is a central pathophysiological factor that links reduced lung function and the severity of obstructive sleep apnea. The aim: To analyze the association between obesity, lung function, and the severity of obstructive sleep apnea (OSA). Methods: A retrospective study was conducted in 28 hospitalized patients at the Clinic for pulmonary diseses of the University Clinical Center of the Republic of Srpska with suspected sleep-disordered breathing. Lung function was assessed by spirometry (forced exiratory volume in 1 second (FEV1), forced vital capacity FVC, FEV1/FVC ratio), while sleep-disordered breathing was diagnosed by nocturnal polygraphy with determination of apnea-hypopnea index (AHI) and oxygen desaturation index (ODI). Results: The subjects were of average age 50 years, predominantly male (68%), with a high average body mass index (BMI) of 40.4 kg/m². The results showed statistically significant positive correlation between BMI and AHI (r = 0.38), as well as a very strong correlation between AHI and ODI (r = 0.91). Negative correlations were observed between AHI and FEV1 (r = -0.45) and FVC (r = -0.40), as well as between BMI and spirometric parameters. Conclusion: Obesity significantly contributes to the reduction of lung function and the severity of OSA.