Risk factors for HCC or ICC were selected using ICD-9-CM codes.31 Liver flukes: 121.3, 121.0; Biliary cirrhosis: 571.6; Cholangitis: 576.1; Cholelithiasis: 574; Choledochal cyst: 751.69; HBV infection: 070.2, 070.3, 070.42, 070.52, V02.61; HCV infection: 070.41,

070.44, 070.51, 070.54, 070.7, V02.62; Unspecified viral hepatitis: 070.9, 070.59, 070.49; Hemochromatosis: 275.0; Wilson’s disease: 275.1. Smoking: V15.82, 305.1, 989.84; Crohn’s disease: 555, 555.0, 555.1, 555.2, 555.9; Ulcerative colitis: 556, 556.0, 556.1, 556.2, 556.3, 556.5, 556.6, 556.9. Alcoholic liver disease was defined as alcoholic fatty liver disease (571.0), alcoholic hepatitis (571.1), alcoholic cirrhosis of the liver (571.2), alcoholic liver damage (571.3), or cirrhosis (571.5, 571.6) in the presence of alcoholism or other alcohol-related disorders (303, 305.0, V11.3, V79.1, 291). Nonspecific CP-673451 in vivo cirrhosis was defined as cirrhosis (571.5, 571.6) without HCV, HBV, or alcoholic liver disease. Age, race/ethnicity (white, black, Hispanic, Asian, other), geographic region (SEER-13 registry region), and state buy-in status were included as covariates. The state buy-in variable indicates whether a third-party pays a beneficiary’s Medicare premiums, and was thus used as an indicator of lower socioeconomic status. Demographic features and preexisting medical conditions were compared between cases and controls

using t tests for continuous variables and chi-square or Fisher’s exact tests for categorical variables. Logistic regression was used to calculate odds ratios (OR) and 95% confidence selleck chemicals llc intervals (95% CI). Wald chi-square tests determined the significance of variables in the logistic regressions. Tests of statistical significance and CIs were two-sided. A P value < 0.05 was considered statistically significant. In addition to the main analyses, several sensitivity analyses were performed. The Thiamine-diphosphate kinase first sensitivity analysis excluded medical conditions diagnosed in the year preceding the cancer diagnosis, whereas the second excluded undifferentiated tumors. Statistical analyses were performed

using SAS, version 9.1 (SAS Institute, Cary, NC). During the study period, 16448 HCC cases and 3005 ICC cases were identified and 3649 HCC cases and 743 ICC cases met the inclusion criteria. Excluded were 6118 HCC and 1317 ICC cases without histopathological confirmation; 75 HCC and 11 ICC cases without known month of diagnosis; 286 HCC and 52 ICC cases with prior cancer diagnoses within the previous 5 years; 6286 HCC and 871 ICC cases who did not meet the age, enrollment interval, or enrollment type criteria; and 34 HCC and 11 ICC cases reported solely by autopsy or death certificate. Population controls included 195,953 persons without any prior cancer diagnosis who met the inclusion criteria as specified above. Table 1 shows the features and demographic characteristics of the study population. The HCC and ICC cases were younger (P < 0.