Association between continuous positive airway pressure and serum aminotransferases in patients with obstructive sleep apnea.

INTRODUCTION: Obstructive sleep apnea (OSA) has been suggested to be a potential contributing factor for nonalcoholic fatty liver disease (NAFLD). Studies on the association between continuous positive airway pressure (CPAP) and NAFLD in OSA patients are limited and controversial.

OBJECTIVES: The aim of this study was to assess the relationship between OSA and NAFLD and the effect of CPAP therapy on serum aminotransferase levels in OSA patients.

METHODS: A total of 160 consecutive patients who underwent standard polysomnography were enrolled. Blood samples were obtained in the morning after sleep for biological profile measurements. Non-invasive ultrasound techniques were used to assess liver steatosis and fibrosis. Within the OSA group, serum aminotransferases were detected before and after CPAP treatment.

RESULTS: Alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyltransferase, and liver steatosis score increased significantly with an increase in OSA severity. Stepwise multiple regression with liver steatosis score, ALT, AST as dependent variable, respectively, apnea-hypopnea index (β = 0.447, p = 0.020; β = 0.266, p = 0.001; β = 0.351, p = 0.020, respectively) significantly predicted the liver steatosis score, ALT, AST after adjustment for confounders. After 3 months of CPAP treatment, there was a significant decrease in both ALT (54.20 ± 24.34 vs. 46.52 ± 24.95, p = 0.000) and AST (31.82 ± 8.91 vs. 29.00 ± 8.34, p = 0.039).

CONCLUSIONS: OSA severity was independently associated with liver steatosis and elevation of serum aminotransferases. 3 months of CPAP therapy were associated with a statistically significant improvement on liver injury in OSA patients.