Prevalence and risk factors for fatty liver in Tunisian adults with obstructive sleep apnea

Introduction: Obstructive sleep apnoea (OSA) is commonly associated with non-alcoholic fatty liver disease (NAFLD). Early identification of NAFLD in OSA patients is important in order to try to prevent its evolution to advanced stages. The objective of this study was to determine the prevalence and risk factors for the occurrence of NAFLD in OSA patients. Method: A cross-sectional analysis including 124 OSA patients examined in the pulmonology department of Abderahmane Mami Hospital between January 2017 and March 2018 was undertaken. NAFLD was diagnosed using an abdominal ultrasonography. Data were analysed in a univariate and multivariate fashion in order to determine the characteristics of OSA patients with and without NAFLD. Results: NAFLD was found in 62.9 % patients, with a frequency according to OSA severity of 51.3 %, 56.5 % and 72.6 % in mild, moderate and severe OSA, respectively. Severe OSA multiplies by 2.32 the risk of having NAFLD. The comparison between groups with and without NAFLD reveals that patients with the disease were younger, more obese, had more severe OSA, lower nocturnal oxygen saturation during sleep, and higher ALAT levels. Multivariate analysis showed a statistically significant link between NAFLD and serum ALAT elevation and the oxygen desaturation index. Conclusions: NAFLD is a frequent comorbidity in OSA, correlated to the severity of the disease. Thus, early screening of the disease in OSA patients especially in younger obese patients with high ALAT serum levels and a high oxygen desaturation index is proposed.