2.2 | Study design
T2DM was diagnosed based on ICD-9-CM code 250.xx with at least 2 outpatient claims within 1 year or one hospitalization. Persons with ICD-9-CM code 571.5, 571.2, or 571.6 for at least 2 outpatient claims within 1 year or one hospitalization were defined as having liver cirrhosis. This method of defining T2DM and liver cirrhosis using ICD-9-CM codes has been validated by studies; [12,13] the diagnostic accuracy of diabetes and cirrhosis is 74.6% and 82.6%, respectively. Persons with liver cirrhosis and esophageal varices with bleeding (456.0 and 456.2), ascites (789.59 and 789.5), hepatic encephalopathy (572.2), or jaundice (782.4) were defined as having decompensated liver cirrhosis [14] and were initially excluded from this study. Patients without these cirrhotic complications were defined as having compensated liver cirrhosis. We excluded persons who were diagnosed as having type 1 diabetes mellitus (ICD-9-CM code 250.1); who did not receive antidiabetic medications; who were younger than 18 years or older than 80 years; who lacked gender information; who died or had renal failure, stroke, ischemic heart disease, heart failure, HCC, esophageal varices with bleeding, ascites, hepatic encephalopathy, jaundice, or hepatic failure before the index date or within 6 months after the index date; and who were diagnosed as having T2DM or cirrhosis during 1997–1999.