Relationship of visceral adiposity index with serum aminotransferase and nonalcoholic fatty liver disease in patients with sleep apnea

Abstract

To evaluate the relationship of visceral adiposity index (VAI) with serum aminotransferase levels and incidence of nonalcoholic fatty liver disease (NAFLD) in patients with sleep apnea (SA). Between January 2011 and December 2014, participants who were referred from Fujian Provincial Sleep-disordered Breathing (SDB) Clinic Center with repeated snoring or a clinical suspicion of SDB were recruited. All individuals underwent polysomnography (PSG) testing and an abdominal ultrasonography scan during this period. They were classified into four groups by apnea-hypopnea index (AHI), non-SA group, mild, moderate and severe group (AHI<5/h, 5-<15/h, 15-<30/h, ≥30/h, respectively). The differences in SA-related parameters, serum aminotransferase and VAI were tested, and the correlations of VAI with indices of PSG and serum aminotransferase were analyzed using Spearman coefficient. Receiver operating characteristic (ROC) curve was conducted to obtain a cut-off value of VAI for predicting NAFLD. Afterwards, logistic regression was performed to analyze VAI's predictive ability regarding incidence of NAFLD in SDB patients. A total of 152 participants including 110 males and 42 females were analyzed, with mean age (51.1±11.3) years. There were 20 subjects in non-SA group, 31 in mild, 39 in moderate and 62 in severe group, with 92 NAFLD patients and 60 controls. No differences in sex, age, alkaline phosphatase were observed among groups according to AHI. However, body mass index, waist circumference, AHI, lowest oxygen saturation, oxygen desaturation index(ODI), VAI, alanine aminotransferase (ALT), aspartate aminotransferase, gamma glutamyltransferase (GGT) and incidence of NAFLD were significantly different among groups. Significant positive relations were observed between VAI and AHI (β=0.222, P=0.006), ODI (β=0.216, P=0.008), ALT (β=0.237, P=0.003), GGT (β=0.238, P=0.003). As shown in ROC curve, the cut-off point of VAI for predicting NAFLD was 1.59 in all individuals. SDB patients with VAI≥1.59 tended to have significantly greater risk in incidence of NAFLD (OR=4.550, P<0.001). VAI was closely associated with increased serum aminotransferase levels and incidence of NAFLD.