Reduce the rate of deaths with hepatitis C as a cause — IID‑16 Data Methodology and Measurement

We obtained and analyzed 2017 national multiple-cause mortality data from NVSS-M using CDC WONDER. Any death record with a report of hepatitis C (ICD-10: B17.1 and B18.2) listed as the underlying or a contributing cause of death in the record axis was included. Rates were standardized to the age distribution of the 2000 U.S. Standard Population (Klein 2001). FOR SINGLE DATA YEARS: Death rates are calculated based on the resident population of the United States for the data year involved. For census years (e.g. 2010), population counts enumerated as of April 1 are used. For all other years, populations estimates as of July 1 are used. Postcensal population estimates are used in rate calculations for years after a census year and match the data year vintage (e.g. July 1, 2011 resident population estimates from Vintage 2011 are used as the denominator for 2011 rates). Intercensal population estimates are used in rate calculations for the years between censuses (e.g. 1991-1999, 2001-2009). Race-specific population estimates for 1991 and later use bridged-race categories. Limitations: First, differences in recording practices of death certificate information may cause misclassification of ICD-10 codes and demographic information. Second, certain racial/ethnic populations likely are underrepresented in US Census data (the denominator for calculating rates), potentially causing overestimated rates for these populations. Third, HCV infections are often underreported as causes of death on death certificates. These analyses do not adjust for deaths resulting from undiagnosed viral hepatitis infections. Some evidence suggests that deaths in HCV-infected persons may have been under enumerated (Ly 2012); the only large US study of deaths among persons with confirmed HCV infection indicated that only 19% had HCV listed anywhere on the death certificate despite 75% having evidence of substantial liver disease (Mahajan 2014). Fourth, Death records listing more than one type of viral hepatitis infection were counted once for each type of infection. For example, a death with ICD-10 codes for both hepatitis B and C virus infections is counted once as a hepatitis B death and once as a hepatitis C death (2016 Surveillance Summary). Note: Estimates for Healthy People 2030 viral hepatitis mortality objectives align with estimates obtained from CDC WONDER and may differ from estimates reported in the annual Viral Hepatitis Surveillance reports due to inclusion of deaths that occurred in the US to noncitizens and use of different age adjustment approach. The Viral Hepatitis Surveillance Summary methodology was developed to align with the methodology presented in the 2008 report The burden of digestive diseases in the United States (Everhart 2008) prepared for the NIH National Institute of Diabetes and Digestive and Kidney Diseases.