Diagnosis and Clinical Implications of Diabetes in Liver Cirrhosis: A Focus on the Oral Glucose Tolerance Test

The liver and skeletal muscles are responsible for maintaining glucose metabolism. As chronic liver disease progresses to cirrhosis, the loss of liver function is exacerbated and leads to the deterioration of skeletal muscle. Consequently, impaired glucose tolerance (IGT) and insulin resistance are often observed in patients with liver cirrhosis. Early stage cirrhosis with hepatogenous diabetes is characterized by marked postprandial hyperglycemia and hyperinsulinemia. Generally, it is possible to underestimate IGT when using either the conventional fasting plasma glucose (FPG) criterion or hemoglobin A1c (HbA1c) levels despite their status as the gold standard for diagnosing diabetes. The number of cirrhotic patients with diabetes tends to be underestimated because many of these patients show lower FPG levels or HbA1c, which masks their IGT. In such cases, the oral glucose tolerance test is recommended to evaluate patients with suspected postprandial hyperglycemia who present with a normal FPG. Moreover, in addition to the Child-Pugh score, the early detection of diabetes may be a useful prognostic marker for patients with liver cirrhosis.