Creating and validating an algorithm to measure AIDS mortality in the adult population using verbal autopsy

Autor: Christl A. Donnelly, Ben Lopman, K Gaitskell, T Harrop, J T Boerma, Simon Gregson, Ruanne V. Barnabas, Godwin Chawira, C Nyamukapa, Geoffrey P. Garnett, Peter R. Mason
Jazyk: angličtina
Rok vydání: 2006
Předmět:
Male
Pediatrics
Epidemiology
lcsh:Medicine
HIV Infections
0302 clinical medicine
Seroepidemiologic Studies
Cause of Death
Surveys and Questionnaires
HIV Infection/AIDS
Childbirth
030212 general & internal medicine
Wasting
Cause of death
education.field_of_study
Medicine in Developing Countries
Mortality rate
Statistics
General Medicine
3. Good health
Infectious Diseases
Caregivers
HIV/AIDS
Female
Public Health
Sexual Health
medicine.symptom
0305 other medical science
Algorithm
Algorithms
Research Article
Adult
Zimbabwe
medicine.medical_specialty
Tuberculosis
Adolescent
Population
Interviews as Topic
03 medical and health sciences
Acquired immunodeficiency syndrome (AIDS)
medicine
Humans
education
030505 public health
business.industry
lcsh:R
medicine.disease
Verbal autopsy
Epidemiology/Public Health
business
Zdroj: PLoS Medicine
PLoS Medicine, Vol 3, Iss 8, p e312 (2006)
ISSN: 1549-1277
Popis: Background Vital registration and cause of death reporting is incomplete in the countries in which the HIV epidemic is most severe. A reliable tool that is independent of HIV status is needed for measuring the frequency of AIDS deaths and ultimately the impact of antiretroviral therapy on mortality. Methods and Findings A verbal autopsy questionnaire was administered to caregivers of 381 adults of known HIV status who died between 1998 and 2003 in Manicaland, eastern Zimbabwe. Individuals who were HIV positive and did not die in an accident or during childbirth (74%; n = 282) were considered to have died of AIDS in the gold standard. Verbal autopsies were randomly allocated to a training dataset (n = 279) to generate classification criteria or a test dataset (n = 102) to verify criteria. A rule-based algorithm created to minimise false positives had a specificity of 66% and a sensitivity of 76%. Eight predictors (weight loss, wasting, jaundice, herpes zoster, presence of abscesses or sores, oral candidiasis, acute respiratory tract infections, and vaginal tumours) were included in the algorithm. In the test dataset of verbal autopsies, 69% of deaths were correctly classified as AIDS/non-AIDS, and it was not necessary to invoke a differential diagnosis of tuberculosis. Presence of any one of these criteria gave a post-test probability of AIDS death of 0.84. Conclusions Analysis of verbal autopsy data in this rural Zimbabwean population revealed a distinct pattern of signs and symptoms associated with AIDS mortality. Using these signs and symptoms, demographic surveillance data on AIDS deaths may allow for the estimation of AIDS mortality and even HIV prevalence.
Based on verbal autopsy from patients in rural Zimbabwe, 69% of deaths were correctly classified as AIDS/non-AIDS. The authors say the method can be used in demographic surveillance on AIDS deaths.
Editors' Summary Background. The worldwide epidemic of HIV/AIDS is at its most severe in poor countries—for example, in Africa, where over 25 million people are estimated to have been infected with HIV. Such countries generally lack the kind of health system that is able to record the cause of death for each person who dies. This makes it very hard to know the number of people whose deaths are related to AIDS. The uncertainty over the AIDS death rates in these countries causes many problems. For example, it will be hard to establish how effective the introduction of AIDS treatment drugs is proving to be in reducing the number of AIDS deaths. A new approach is needed to determine and record the causes of deaths in these countries. It is not enough to rely on knowing whether the person who has died has been found to be HIV positive; many people in poor countries who have AIDS have never been tested, and, in any case, the cause of death in a person with HIV may not necessarily be related to the virus. Why Was This Study Done? The researchers wanted to investigate the use of the technique called “verbal autopsy.” This involves asking those who were with the deceased person before they died—usually close family members—a series of standard questions about the symptoms the person had. This is now a recognized technique, but the researchers wanted to know specifically how effective it can be in identifying AIDS as the cause of death. It is also important to “validate” the set of questions chosen to be used in a verbal autopsy, to see how likely they are to produce the correct explanation for the cause of death. What Did the Researchers Do and Find? The researchers drew up a list of what they considered appropriate questions and used them in interviews (conducted by nurses) with the caregivers of 381 adults who died between 1998 and 2003 in Manicaland, a rural area of eastern Zimbabwe. For all of these people, it was known whether they were HIV positive or HIV negative. (This information is not known for most deaths in rural Zimbabwe.) The 282 people who were HIV positive and did not die in an accident or during childbirth were considered by the researchers to have died of AIDS. (They argue this was a reasonable assumption to make, based on what is already known about death rates in HIV-positive and HIV-negative people in Zimbabwe.) The questions the caregivers were asked about the condition of the person who died included whether or not they had any of the following signs or symptoms that are common among patients with AIDS: moderate or severe weight loss, jaundice, herpes zoster, presence of abscesses or sores, oral candidiasis, acute respiratory tract infections, and vaginal tumours. Explanations of what these conditions looked like were given to the caregivers. There were also questions on the circumstances surrounding each death. Using the answers to the questions, it was possible in 69% of cases to make a correct decision as to whether the death was the result of AIDS. What Do These Findings Mean? A verbal autopsy using the signs and symptoms selected by these authors can be used to make reasonable estimates of the number of AIDS deaths. The authors believe that, with the same set of questions, it might also be possible to produce estimates of the number of people living with HIV/AIDS. Validation of the questions used should, however, be carried out separately in each country that adopts this technique. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0030312. • MedlinePlus has many pages providing information about HIV/AIDS. • Information about the global epidemic of HIV/AIDS and international efforts to fight it can be found on the Web site of the Joint United Nations Programme on HIV/AIDS (UNAIDS). • Of particular relevance is UNAIDS' country-by-country analysis of the situation in Africa. • The World Health Organization's pages on HIV/AIDS. A recent discussion on verbal autopsies has been published by WHO. • The Manicaland HIV/STD Prevention Study.
Databáze: OpenAIRE
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