The correlations between socioeconomic status and intrahepatic cholangiocarcinoma in the United States: a population-based study

BACKGROUND: The incidence and mortality rates of intrahepatic cholangiocarcinoma (ICC) continue to increase in the United States (US). To our knowledge, the associations between socioeconomic factors (SES) and ICC-associated incidence and survival are still unclear. METHODS: We identified patients with ICC in the US Surveillance, Epidemiology, and End Results (SEER) database between 2011 and 2015. ICC incidence rates were calculated by directly age-adjusted to the 2000 US population. Univariate and multivariate Cox regression analyses were performed to find the influence of SES on ICC cause-specific survival (CSS) and overall survival (OS). Using disadvantageous SES, we generated a prognostic score model for risk stratification, then Kaplan-Meier analysis was performed to find the influence of SES on for ICC CSS/OS. RESULTS: A total of 3,456 ICC patients were included. Rates ratios (RR) for ICC incidence rates increased monotonically with ages and decreased with increasing county education levels. From three disadvantageous socioeconomic factors (i.e., unmarried status, uninsured status, median household income <US$5,289), the prognostic score model generated four risk subgroups with scores of 0, 1, 2 or 3, which had significantly separated CSS/OS curves (all P<0.001). The stratified analysis revealed that low-risk patients (score 0–1) could obtain a better CSS/OS than high-risk patients (score 2–3) at both gender and age subgroups. CONCLUSIONS: Low county education levels may be associated with increased ICC risk. Median household income, insurance status, and marital status were significant predictors of survival outcomes. Low-risk socioeconomic status (SES) confers protective effects in ICC.