Changes over time in hepatic markers predict changes in insulin sensitivity, β -cell function, and glycemia

Abstract

Context Serum concentrations of liver enzymes and the hepatokine fetuin-A have been linked to the risk of type 2 diabetes, but their longitudinal impact on insulin resistance and β-cell dysfunction is unclear. Objective To evaluate the impact of changes over 2 years in fetuin-A and the liver enzymes alanine aminotransferase (ALT), aspartate aminotransferase (AST), and 3-glutamyltransferase (GGT) on changes in insulin sensitivity, β-cell function, and glycemia in women with varying degrees of previous gestational dysglycemia, reflecting a range of future diabetic risk. Design/Setting/Participants In total, 336 women underwent glucose challenge test (GCT) and oral glucose tolerance test (OGTT) in pregnancy, followed by repeat OGTT and measurement of ALT/AST/GGT/fetuin-A at both 1 year and 3 years postpartum. The antepartum GCT/OGTT identified four gestational glucose tolerance groups: gestational diabetes (n = 104), gestational impaired glucose tolerance (n = 59), abnormal GCT with normal OGTT (n = 98), and normal GCT/OGTT (n = 75). Results At 1 and 3 years postpartum, ALT, AST, GGT, and fetuin-A did not differ across the four groups, but the intervening change in ALT/AST ratio was greater in the gestational dysglycemia groups (P = 0.05). Higher baseline ALT/AST (t = -1.99, P = 0.05) and fetuin-A (t = -3.17, P = 0.002) predicted lower insulin sensitivity (Matsuda) at 3 years, as did their respective changes from 1 to 3 years (ALT/AST: t = -5.47, P < 0.0001; fetuin-A: t = -3.56, P = 0.0004). Change in ALT/AST predicted lower β-cell function (t = -2.33, P = 0.02) and higher fasting glucose at 3 years (t = 2.55, P = 0.01). Moreover, baseline fetuin-A predicted prediabetes/diabetes at 3 years (OR, 1.38; 95% CI, 1.01 to 1.88). Conclusion Circulating hepatic markers, particularly ALT/AST ratio and fetuin-A, track with changes in insulin sensitivity and β-cell function, supporting a pathophysiologic basis in their prediction of diabetic risk.