AIDS Cause of Death reallocation visualiser


This tool visualises HIV/AIDS deaths recorded in national vital registration systems, including reallocation of deaths to HIV/AIDS that were initially classified as unknown causes or misclassified as other causes. Estimates of AIDS deaths adjusted for misclassification are produced for the Global Burden of Disease Study by the Institute for Health Metrics and Evaluation.

Vital registration systems use the International Classification of Diseases (ICD) system to facilitate systematic recording of mortality data. Misclassification of AIDS deaths, however, is common: deaths can be incorrectly recorded as an immediate cause of death (e.g. respiratory failure, cardiac arrest), or an intermediate cause of death (e.g. sepsis, heart failure).

The Case Surveillance and Vital Registration model (CSAVR) uses data about the number of AIDS deaths in each year to back-calculate HIV infections and the number of people living with HIV. Estimates may be inaccurate if the input data about the number of AIDS deaths do not include those that have been initially misclassified as unknown or other causes. UNAIDS recommends to use mortality data corrected for misclassification provided by the Global Burden of Disease Study when using CSAVR.

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GBD2019 AIDS death estimates use mortality data up to 2016, and may not align with mortality estimates beyond 2016. GBD2020 AIDS death estimates will be added to this tool when publicly available.


Deaths coded as HIV/AIDS are blue. Deaths coded as garbage codes reallocated to HIV/AIDS are yellow. Deaths coded as other causes reclassified to HIV/AIDS are red.

Methods and sources


Methods

Data about the number of HIV/AIDS deaths corrected for unknown and misclassified causes of death are estimated as part of the Global Burden of Disease Study produced by the Institute of Health Metrics and Evaluation. Methods for estimating AIDS deaths include cause of death reallocation are described in Kyu et al. (2021, in press) and summarised below.

Deaths recorded in vital registration may be assigned immediate, contributing, and underlying causes of death classified according to the International Classification of Diseases (ICD) system. Most deaths for which HIV/AIDS was the underlying cause are correctly attributed to HIV/AIDS at the time of death. The cause of death reclassification process involves reassigning some deaths that were probably due to HIV/AIDS but for which AIDS was not recorded as the cause at the time of death.

This involves reclassification of deaths from two sources: (1) Deaths for which the immediate, intermediate, or ill-defined causes are incorrectly recorded as the underlying cause of death. These are often referred to as 'garbage' codes. (2) HIV/AIDS deaths for which the underlying cause was misclassified as a different cause of death.

Garbage code correction

Cases where ICD codes for immediate causes, intermediate causes, or ill-defined causes of death are recorded as the underlying cause of death are often referred to as ‘garbage codes’ as they do not represent the underlying cause of death that initiated the chain of events leading to death.

Correcting for garbage codes addresses three issues:

  • Reclassifying deaths which were incorrectly assigned intermediate causes (e.g., sepsis) or ill-defined causes (e.g. unknown causes of death, ill-defined intestinal infections) as the underlying cause of death.
  • Reclassifying relevant garbage codes such as unspecified immunodeficiency as HIV/AIDS deaths.
  • Reclassifying diseases that can mimic HIV infection (e.g., inflammatory bowel disease, some skin diseases) to HIV/AIDS deaths.

The reassignment of deaths to HIV/AIDS is based on the level of regional increase in the mortality rate of ICD codes relative to the rates observed during the pre-HIV era from 1980 to 1984. It is assumed that an increase of more than 5% is HIV/AIDS‐related, and the proportion of those excess deaths over 5% is reassigned to HIV/AIDS. This method is used for specific recorded causes of death, including bacterial infections and immunodeficiencies.

When causes of death are ill-defined, multiple causes of death recorded within the vital registration system are used to redistribute deaths to HIV/AIDS. Multiple causes of death data include a combination of an underlying cause of death and other causes such as immediate and intermediate causes that were included in the chain of events leading to death. Analysing multiple causes of death data can provide insight into identifying the true underlying cause of death when the recorded cause of death is ill-defined.

Misclassification correction

HIV deaths that were incorrectly assigned to other underlying causes such as tuberculosis and encephalitis are reallocated as follows:

  1. Examine the age patterns of underlying causes in location and years with and without HIV epidemics and isolate the causes with age pattern shifts during the epidemic years
  2. Compute the expected deaths by location, year and sex for each underlying cause with an age-pattern shift
  3. Attribute expected deaths to the corresponding underlying cause
  4. Compute the difference between observed and expected deaths and reallocate the difference to HIV/AIDS.

Mortality group

Data sources



Citations

Wang et al. (2016) Global, regional, and national life expectancy, all-cause mortality, and cause-specific mortality for 249 causes of death, 1980–2015: a systematic analysis for the Global Burden of Disease Study 2015

Birnbaun et al. (2011) Exposing misclassified HIV/AIDS deaths in South Africa