Hepatitis C virus infection mortality trends according to three definitions with special concern for the baby boomer birth cohort.

We examined mortality trends of hepatitis C virus (HCV) infection in the United States in 1999‐2018 according to the following definitions: HCV as the underlying cause of death (UCOD), HCV mentioned anywhere on the death certificate (mentioned), and HCV recorded in Part 1 of the death certificate. By using entity axis information in mortality multiple‐cause files, we ascertained the position of HCV on the death certificate. Joinpoint regression analysis was used to evaluate changes in HCV mortality rates according to the definitions. The age‐standardized HCV mortality rates (deaths per 100,000 people) in terms of UCOD, mentioned, and Part 1 were, respectively, 1.36, 2.87 and 1.94, in 1999; increased to 1.90, 5.09 and 2.96 in 2013; and declined to 0.98, 3.77 and 2.29 in 2018. The mentioned/UCOD mortality ratio was 2.11 in 1999 and increased to 3.86 in 2018. The mentioned/Part 1 ratio was almost identical (ie 1.48 in 1999 and 1.65 in 2018). The extent of decline from 2014 to 2018 differed according to the definitions; the annual per cent changes for UCOD, mentioned, and Part 1 were −14.6%, −7.1% and −9.8%, respectively. For the same age group, the baby boomer subcohort 1950‐1954 had the highest mortality rates among the subcohorts (1945‐1949, 1955‐1959 and 1960‐1964). HCV mortality according to HCV in Part 1 of the death certificate—the explicit opinion of a certifying physician that HCV played a substantial role and directly caused death—differed from that according to HCV as UCOD and HCV mentioned. [ABSTRACT FROM AUTHOR]