Jianguo Chen, Guangwei Yang, Xiaodong Sun
Mortality coded to ICC increased substantially in the United States from 1999 through 2024, with marked heterogeneity by sex, age, race and ethnicity, and geography. These descriptive findings distinguish populations with high absolute mortality from those with rapid relative increases, but they do not establish the causes of the observed trends.
BACKGROUND: Contemporary national estimates of intrahepatic cholangiocarcinoma (ICC) mortality extending through 2024 are limited. We examined long-term temporal trends and demographic and geographic disparities in ICC mortality among adults in the United States.
METHODS: We conducted a serial cross-sectional analysis of the Centers for Disease Control and Prevention Wide-ranging Online Data for Epidemiologic Research (CDC WONDER) Underlying Cause of Death databases. Deaths among US adults aged 25 years or older from 1999 through 2024 were identified using International Classification of Diseases, 10th Revision code C22.1 as the underlying cause of death. Mortality was examined by year, sex, age, race and ethnicity, US Census region, and state from 1999 through 2024; urban-rural analyses were restricted to 1999-2020 because later data were unavailable in the extracted database. Crude mortality rates and age-adjusted mortality rates (AAMRs) per 100,000 population were calculated. Joinpoint regression was used to estimate annual percent changes (APCs) and average annual percent changes (AAPCs) with 95% confidence intervals (CIs).
RESULTS: From 1999 to 2024, 143,345 ICC deaths were recorded among adults aged 25 years or older. Annual deaths increased from 2,552 to 9,752 (282.13%), and the AAMR rose from 1.44 to 3.35 per 100,000 (AAPC, 3.38%; 95% CI, 3.24%-3.52%). In 2024, the AAMR was higher in men than women (3.70 vs 3.11), although the increase was faster in women (AAPC, 3.56% vs 3.15%). Adults aged 85 years or older had the highest crude mortality rate (16.89), whereas those aged 35-44 years had the fastest increase (AAPC, 4.13%). Hispanic individuals had the highest AAMR (3.47), while non-Hispanic Black individuals had the largest AAPC (4.03%). The Midwest had both the highest AAMR (3.68) and fastest increase (AAPC, 3.62%). From 1999 to 2020, metropolitan areas had slightly higher AAMRs and faster increases than nonmetropolitan areas.
CONCLUSIONS: Mortality coded to ICC increased substantially in the United States from 1999 through 2024, with marked heterogeneity by sex, age, race and ethnicity, and geography. These descriptive findings distinguish populations with high absolute mortality from those with rapid relative increases, but they do not establish the causes of the observed trends.