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DATA METHODS

DATA RELEASE

To permit the display of HIV care continuum indicators for each city, a data release agreement was obtained from the following health departments overseeing HIV surveillance in the each jurisdiction:

  1. Atlanta (Georgia Department of Public Health, Division of Health Protection, Epidemiology Program, HIV/AIDS Epidemiology Section)
  2. Chicago (Chicago Department of Public Health, STI/HIV Division, Surveillance, Epidemiology and Research Section)
  3. New Orleans (Louisiana Department of Health and Hospitals, Office of Public Health, STD/HIV Program)
  4. Philadelphia (Philadelphia Department of Public Health, AIDS Activities Coordinating Office)
  5. Washington, D.C. (District of Columbia Department of Health, HIV/AIDS, Hepatitis, STD, and TB Administration)

DATA AND DEFINITIONS:

HIVContinuum allows viewers to look at ZIP Code/ward-level HIV surveillance data by race/ethnicity, sex and age groups. Maps for Atlanta, Chicago, New Orleans and Philadelphia display data by ZIP Code; maps for Washington, D.C. display data by ward. The residence at the time of HIV diagnosis was used for all maps. The black and white race groups are non-Hispanic, and the Hispanic/Latino ethnicity is inclusive of all races. Sex was defined as "sex at birth." Cases were assigned to age groups based on age the time of HIV diagnosis. Caution should be exercised when viewing and interpreting the new diagnosis data on the ZIP Code/ward maps because the scales change across the different breakdowns; the correct scale is always displayed adjacent to the map, regardless of the breakdown.

The definitions of the HIV care continuum indicators used on this website are:

  1. New HIV Diagnoses: This value represents the 5-year (2007-2011) risk of new HIV diagnosis among the adult/adolescent population within each ZIP Code/ward. This indicator is not a rate of new diagnosis. The numerator is the number of new HIV diagnoses between 2007- 2011, inclusive, among those aged 13 years and older at diagnosis. The denominator for this proportion is the 2010 census population aged 13 years and older obtained from the U.S. Census Bureau (2010 Census Summary File 2 - Dataset SF-2, Table PCT3, Total Population, White/Not Hispanic or Latino, Black or African-American/Not Hispanic or Latino, Hispanic or Latino).
  2. Late HIV Diagnoses: This value represents the proportion of adults/adolescents diagnosed with HIV between 2007-2011 within each ZIP Code/ward who were diagnosed late in the HIV disease process. The numerator is the number of individuals aged 13 years and older at HIV diagnosis, diagnosed between 2007 and 2011, who were diagnosed with immunologic or clinical AIDS (new CDC classification as A3, B3, or C1-C3) within 3 months of initial HIV diagnosis. The denominator is the number of individuals aged 13 years and older who were newly diagnosed with HIV from 2007-2010.
  3. Linkage to HIV Care: This value represents the proportion of adults/adolescents diagnosed with HIV between 2007-2011 within each ZIP Code/ward who were linked to HIV care within 3 months of their diagnosis. The numerator is the number of individuals aged 13 years and older at HIV diagnosis, who were diagnosed from 2007-2011, and with a reported CD4 or HIV viral load (VL) count within 3 months of their initial HIV diagnosis. The denominator is the number of individuals aged 13 years and older who were newly diagnosed with HIV from 2007-2011 and living in 2012.
  4. Engagement in HIV Care: This value represents the proportion of adults/adolescents diagnosed with HIV from 2007-2011 within each ZIP Code/ward and living in 2012 who were engaged in care in 2012. The numerator is the number of individuals aged 13 years and older at HIV diagnosis, who were diagnosed from 2007-2011, were living in 2012, had at least one previously reported CD4 or VL count that was not on the same date as their HIV diagnosis (i.e., those who started care), and had at least one reported CD4 or VL count in calendar year 2012. The denominator is the number of individuals aged 13 years and older at HIV diagnosis, who were diagnosed 2007-2011, were living in 2012, and had at least one previously reported CD4 or VL count that was not on the same date as their HIV diagnosis.
  5. HIV Viral Load Suppression Among Those Engaged in Care: This value represents the proportion of adults/adolescents diagnosed with HIV from 2007-2011 within each ZIP Code/ward and engaged in care in 2012 who had a suppressed HIV viral load. The numerator is the number of individuals aged 13 years and older at HIV diagnosis, who were diagnosed 2007-2011, living in 2012, had a reported VL count in 2012 (i.e., engaged in care in 2012), and the most recently reported VL count was < 200 copies/ml. The denominator is the number of individuals aged 13 years and older at HIV diagnosis, who were diagnosed 2007-2011, living in 2012, and had a reported VL count in 2012.
  6. HIV Viral Load Suppression Among Those Newly Diagnosed: This value represents the proportion of adults/adolescents diagnosed with HIV from 2007-2011 within each ZIP Code/ward who had a suppressed HIV viral load. The numerator is the number of individuals aged 13 years and older at HIV diagnosis, who were diagnosed 2007-2011, living in 2012, and the most recently reported VL count was < 200 copies/ml. The denominator is the number of individuals aged 13 years and older at HIV diagnosis, who were diagnosed 2007-2011.

For ZIP Codes/wards that house correctional institutions, caution should be exercised when interpreting the data as these statistics are inclusive of institutional populations and their inclusion may artificially inflate the actual rate and case count of a ZIP Code/ward when an institution is housed in it.

As is standard in the display of health statistics, data generated from a numerator less than 12 are considered unstable and should be interpreted with caution. If a specific ZIP Code/ward meets the criterion for instability, a message in the balloon will appear when you place your mouse cursor over the ZIP Code/ward noting that the reported value is unstable.

To protect the confidentiality of persons living with an HIV/AIDS diagnosis, HIVContinuum does not display new diagnosis data when the numerator (number of persons living with an HIV/AIDS diagnosis) is less than 5 and/or the denominator (number of people in the ZIP Code/ward in that population group) is less than 500. Suppression of other indicators is as follows:

  1. Atlanta: Values are suppressed if either the numerator or denominator is less than 5.
  2. Chicago: Values are suppressed if either the numerator or denominator is less than 5.
  3. New Orleans: Values are suppressed if either the numerator or denominator is less than 5.
  4. Philadelphia: Values are suppressed if either the numerator or denominator is less than 6.
  5. Washington, D.C.: Values are not suppressed. Values are not shown only if both the numerator and denominator are less than 5.

ZIP Codes/wards appear in a shade of gray when one or both of these conditions for suppression are met (see footnote below map scale).

Suppression should be interpreted with caution.

Each public health department defined the geographic level (e.g., ZIP Codes or wards) in their jurisdiction for which they desired to display data on HIVContinuum. For details regarding each jurisdiction's assignment of ZIP Codes to cases missing an address at diagnosis, or to other data-related issues, see the Data Caveats table below. Denominators used to calculate new diagnosis data for wards in Washington DC were obtained by aggregating U.S. Census Bureau 2010 estimates of census tract populations. Denominators used to calculate new diagnosis data for ZIP Codes were obtained from the U.S. Census Bureau's 2010 census of ZIP Code Tabulation Areas (ZCTAs). Additional information on ZCTAs can be found here.

Data for HIV testing sites were obtained from the Centers for Disease Control and Prevention, National Prevention Information Network as an ongoing data access request. Ryan White HIV/AIDS Medical Care provider data for HIV care sites were obtained from the Health Resources and Services Administration, HIV/AIDS Bureau as an annual data request.

Range intervals for new diagnosis data for each city were defined using quintiles of the overall new diagnosis data for each city. New diagnosis data stratified by age, race and sex within each city are displayed using these same ranges. Other indicators are displayed using pre-defined ranges that are not specific to each city. For linkage to HIV care and engagement in HIV care, we defined the best category (lightest color) at 90% or greater as it meets or exceeds the 2015 target in the US National HIV/AIDS Strategy. For late diagnosis, we defined the best category as 10% or less derived from the National HIV/AIDS Strategy target of increasing awareness of HIV status to more than 90% of those with HIV infection. For viral suppression among those engaged in care, we defined the best category of 90% or greater based on the CDC's HIV Strategic Plan in response to National HIV/AIDS Strategy requiring a 10% improvement over the baseline of 77% with suppressed virus among patients in care reported by the Medical Monitoring Project.

HIV CARE CONTINUUM INDICATORS ON THE CHART:

Each box in the charts represents the mode (i.e. the most commonly occurring) category for each combination of demographic stratification and HIV care continuum indicator at the ZIP Code/ward level. Since ranges for new diagnoses are defined based on the distribution of the overall new diagnosis data within each city, each category of overall new diagnoses occurs with the same frequency and the mode of these data cannot be displayed.

The best categories (lightest color) for late diagnosis (< 10%), linkage (> 90%), engagement (> 90%) and viral suppression (> 90%) are based on targets in the National HIV/AIDS Strategy and the CDC's HIV Strategic Plan. Categories depicted in darker colors represent worsening gaps in achieving these targets.

COMPARABILITY OF DATA ACROSS CITIES:

The case definitions and data systems for new HIV diagnoses and late HIV diagnoses are standard in HIV case surveillance, but standardization for the other indicators used here is still a work-in-progress. In these 5 cities, the public health authority requires that all CD4 and HIV viral load tests be reported, regardless of the result. Though most of these reports come directly from laboratories, the degree of completeness of reporting and the ability to link laboratory results to diagnosed cases both within and across jurisdictions is unknown. Therefore, direct comparisons of these indicators between cities should not be made. The main utility of HIVContinuum is to visualize patterns in the HIV care continuum within each city.

DATA CAVEATS:

  1. ATLANTA

    Atlanta data reflect cases entered through 12/31/2014 and are based on residence at diagnosis as reported in Georgia's Electronic HIV/AIDS Reporting System (eHARS). Data reflect cases from ZIP Codes in Clayton, Cobb, DeKalb, Douglas, Fulton and Gwinnett Counties. Cases missing ZIP Code at diagnosis are excluded from the analysis.
  2. CHICAGO

    Chicago data reflect new HIV cases reported and entered through 12/23/2013. Cases missing address or ZIP Code at diagnosis are excluded from the maps. Homeless cases with addresses of a shelter at diagnosis were assigned to the ward of the homeless shelter.
  3. NEW ORLEANS

    New Orleans data represent persons newly diagnosed with HIV in the City of New Orleans between 2007-2011 and who were reported as of 10/30/2014. Cases missing ZIP Code at diagnosis are excluded from the maps.
  4. PHILADELPHIA

    Philadelphia data represent persons newly diagnosed with HIV in the City of Philadelphia 2007-2011 and who were reported as of 12/31/2012. Data reflect cases from ZIP Codes in Philadelphia County only. Cases missing address or ZIP Code at diagnosis are excluded from the maps. Cases diagnosed in a correctional facility were assigned to the ZIP Code of the correctional facility.
  5. WASHINGTON, D.C.

    Washington, D.C. data reflect resident cases newly diagnosed and reported through 12/31/2012. Cases with missing address information at diagnosis were not included in this analysis. Cases diagnosed in a correctional facility were assigned the ward of the correctional facility. Homeless cases with addresses of a shelter at diagnosis were assigned to the ward of the homeless shelter.