Hepatitis C Prevalence Estimates
The state-level chronic and antibody hepatitis C prevalence estimates presented on HepVu were obtained from the Coalition for Applied Modeling for Prevention (CAMP) at Emory University. These estimates were calculated using four publicly available data sources – National Health and Nutrition Examination Survey (NHANES), National Vital Statistics System (NVSS), American Community Survey (ACS) Public Use Microdata Samples (PUMS), and U.S. Census data – intercensal data (1999-2012).
Weighted sampled NHANES data represent all non-institutionalized people 6 years of age and older residing in the 50 states and the District of Columbia (DC). Demographic information and blood specimens are collected by the NHANES. For the CAMP analyses, persons with confirmed positive anti-HCV antibody results were considered to have prevalent hepatitis C virus infection, and persons with a positive or indeterminate anti-HCV test and positive HCV RNA test were considered to have chronic hepatitis C infection. NHANES data and corresponding sampling weights are released every two years, so data from seven cycles were used, representing a 14-year span (1999-2012). NHANES responses were grouped by demographic information. Sex was categorized into male and female. Race/ethnicity was categorized into Hispanic, non-Hispanic white, and non-Hispanic black. Age was categorized into three birth cohorts – before, during, and after 1945-1965.
The NVSS data are collected using information from death certificates of all U.S. residents within the 50 states and DC. Deaths of residents of Puerto Rico, other U.S. territories, and fetal deaths are not included. Demographic, geographic, and cause-of-death information for each individual is recorded. Any records that included the ICD-10 code for acute viral hepatitis C (B17.1) or chronic viral hepatitis C (B18.2) as the underlying or multiple cause of death were used to identify deaths related to hepatitis C.
The ACS provides PUMS data as records at the individual person or housing unit level with response information such as sex, age, and other characteristics. The 5-year PUMS files were used for the modeled estimates and are the multiyear combinations of the single year ACS data. Inflation adjustment factors and weights were adjusted appropriately for the 5-year PUMS files. State-by-demographic group population totals from the 2006-2010 5-year ACS estimates were used in calculations to determine hepatitis C prevalence in each state in 2010.
The U.S. Census Bureau produces demographic and geographic data through decennial censuses, annual surveys, and population estimates and projections. Annual intercensal population estimates datasets were used to provide denominators for HCV mortality rates for each year during 1999-2012.
The hepatitis C chronic and antibody prevalence estimates analyses were restricted to people aged 18 years of age or older, living within the 50 states and DC. The NHANES data were used to calculate direct weighted estimates of national hepatitis C chronic and antibody prevalence in 18 strata formed by levels of sex (2), race/ethnicity (3), and birth cohort (3). To limit population totals to the same population that are eligible to be sampled by NHANES, respondents living in institutionalized group quarters were removed from the Public Use Microdata Samples (PUMS) from the 2006-2010 ACS 5 year data. The 2006-2010 ACS PUMS were weighted to generate estimated population totals for the same 18 strata within each state. These state-by-strata population totals were multiplied by the stratified hepatitis C chronic and antibody prevalence estimates to generate crude state-level estimates (adjusted for sex, race, and age). NVSS mortality data and intercensal population totals were used to model the HCV-related death rate in the same 18 strata within each state. The state-by-strata HCV-related death rates were then compared to the national HCV-related death rate in each strata, to create a ratio of state-by-demographic group stratum effects. The state effects ratios were multiplied by the crude state-level chronic and antibody prevalence estimates to generate mortality-adjusted HCV chronic and antibody prevalence totals in each strata in each state. These were summed across strata and combined with 2006-2010 ACS population totals data to generate the HCV chronic and antibody prevalence estimates by each demographic group in each state.
Rates are expressed as the number of estimated cases per 100,000 people in the population, rounded to the nearest ten persons. It is an expression of the relative concentration of estimated people with hepatitis C in an area (state). Estimated cases are rounded to the nearest hundred persons.
The range around each estimate is the 95% confidence interval. These intervals incorporate the joint statistical uncertainty of the stratified NHANES prevalence estimates in each demographic group and the modeled hepatitis C mortality rates. The 95% confidence intervals were constructed using a Monte Carlo simulation with 10,000 runs that resampled values from those two original distributions.
Hepatitis C Mortality Data
The state-level hepatitis C mortality data presented on HepVu were obtained from the Centers for Disease Control and Prevention (CDC) WONDER Online Database System and compiled by researchers at the Rollins School of Public Health at Emory University. The CDC WONDER data are collected using information from death certificates of all U.S. residents within the 50 states and DC. Deaths of residents of other U.S. territories and fetal deaths are not included. Demographic, geographic, and cause-of-death information for each individual is recorded. Any records that included the ICD-10 code for acute viral hepatitis C (B17.1) or chronic viral hepatitis C (B18.2) as the underlying or multiple cause of death were used to identify deaths related to hepatitis C.
If the death count for any particular group/state is less than 10, data are suppressed and appear as no color (white) on the maps. If the death count for any particular group/state is 10 or greater and less than 20, then the rate generated from that count is considered unreliable.
HepVu allows viewers to look at hepatitis C prevalence estimates and mortality data at the overall state-level for cases and rates, as well as stratified by sex, race, and age groups.
The chronic and antibody prevalence estimates display sex as male or female; race as Hispanic/other, non-Hispanic White and non-Hispanic Black; and age as before, during, and after 1945-1965.
The mortality data display sex as male of female; race as non-Hispanic American Indian or Alaska Native, non-Hispanic Asian or Pacific Islander, non-Hispanic Black/African American, non-Hispanic White, and Hispanic/Latino origin ; and age as three birth cohorts – younger than Baby Boomers (0-49), Baby Boomers (50-69), and older than Baby Boomers (70+).
Displayed Legend Values
Legend values were developed by calculating deciles in SAS analytic software (SAS Institute, Cary, NC) and rounding to create the legend values for each group. In order to illustrate the variation in rates and case counts, values were developed specific to each demographic grouping (i.e., overall, and separately by sex, by race, and by age group). Thus, a total of 8 map scales exist (rate/case count by overall/sex/race/age group) for each of the chronic, antibody, and mortality data. Because the ranges that produce the map colors may differ, users should be careful in comparing maps between demographic categories (sex, race, and age group).
|Data Element||Location on HepVu||Data Source||Anticipated Update Frequency on HepVu Website|
|Estimated Rates and Case Counts of Persons Living with HCV, State Data||Maps||Emory Coalition for Applied Modeling for Prevention (CAMP); Data Request. May 2018.||When Available|
|Estimated Rates and Case Counts of Persons Living with Hepatitis C Antibodies, State Data||Maps||Emory Coalition for Applied Modeling for Prevention (CAMP); Data Request. June 2017.||When Available|
|Rates and Case Counts of Hepatitis C Mortality, State Data||Maps||Centers for Disease Control and Prevention. National Center for Health Statistics. CDC WONDER Online Database. https://wonder.cdc.gov/mcd-icd10.html
|2010 Population||Profile||U.S. Census Bureau, 2010 Census. March 2018.||When Available|
|HIV Data||Maps||AIDSVu, Emory University, Rollins School of Public Health; www.aidsvu.org. September 2016.||Annually|