Data Methods

Learn more about the data that informs AHEAD.

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Linkage to HIV medical care indicator icon Linkage to HIV medical care

The linkage to HIV medical care indicator is measured by documentation of at least one CD4 or viral load test performed ≤1 month after diagnosis. Of note, this indicator is only available for states that have complete data. These states have reported at least 95% of laboratory results to their surveillance programs and have transmitted their data to CDC’s National HIV Surveillance System (NHSS). NHSS includes data for persons aged > 13 years. 

For the baseline year 2017, linkage to HIV medical care was available for 41 states and the District of Columbia: Alabama, Alaska, California, Colorado, Connecticut, Delaware, Florida, Georgia, Hawaii, Illinois, Indiana, Iowa, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, New Hampshire, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Virginia, Washington, West Virginia, Wisconsin, and Wyoming. 

There are 41 areas with complete lab reporting for 2018; however, the composition of the states changed. In 2018, linkage was available for Nevada but not available for Connecticut. 

For 2019, 2020, and 2021, the number of jurisdictions with complete laboratory data increased to 45. Linkage to HIV medical care data is available for 44 states and the District of Columbia including: Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, Florida, Georgia, Hawaii, Illinois, Indiana, Iowa, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Virginia, Washington, West Virginia, Wisconsin, and Wyoming.

Formula for the Linkage to Care indicator

 

Completeness of reporting varies among states and local jurisdictions. Data should be interpreted with caution for EHE areas (including Phase 1 EHE states, EHE jurisdictions, or states that contain EHE jurisdictions) that do not have laws requiring complete reporting of laboratory data or have incomplete reporting. 

  • EHE areas without laws requiring complete reporting include:
    • Idaho
    • New Jersey
  • EHE areas with incomplete reporting of linkage to care include:
    • Arizona (Missing for 2017 & 2018)
    • Arkansas (Missing for 2017 & 2018)
    • Connecticut (Missing for 2018)
    • Idaho (Missing for 2017, 2018, 2019, 2020 & 2021)
    • Kansas (Missing for 2017, 2018, 2019, 2020 & 2021)
    • Kentucky (Missing for 2017, 2018, 2019, 2020 & 2021)
    • Nevada (Missing for 2017)
    • New jersey (Missing for 2017, 2018, 2019, 2020 & 2021)
    • Pennsylvania (Missing for 2017, 2018, 2019, 2020 & 2021 though, jurisdictional data for Philadelphia is available)
    • Vermont (Missing for 2017, 2018, 2019, 2020 & 2021)
    • Puerto Rico (Missing for 2017, 2018, 2019, 2020 & 2021)

Linkage to HIV medical care data is updated quarterly. It is important to note that data presented by quarter are preliminary and include cumulative counts of HIV diagnoses through the specified quarter of the corresponding calendar year. Also, a three-month reporting lag is required for calculating linkage to HIV medical care due to known delays in reporting of laboratory data (for example, linkage to HIV medical care through September 2020 is calculated using data reported to CDC’s National HIV Surveillance System through December 2020). Data presented by quarter are preliminary. 

More information can be found at: HIV Surveillance Report Supplemental Report Volume 26, Number 2.