HIV/AIDS deaths in South Africa are substantially underreported

HIV/AIDS related deaths in South Africa are commonly attributed to TB or other AIDS-related conditions without any reference to underlying HIV disease on the death certificate. As a result, cause-of-death statistics in South Africa cannot be taken at face value, according to a report in the January 28^th issue of AIDS.

After a closer inspection of the mortality data, with special attention to the age of death, researchers from Medical Research Council and University of Cape Town conclude that the actual number of AIDS-related death is dramatically higher than official South African figures suggest.

Background

The extent of AIDS mortality in South Africa is a very controversial subject. If no longer a total sceptic about HIV/AIDS, President Thabo Mbeki continued to play down its impact in his country even while the government was preparing for the roll-out of antiretroviral therapy. On a trip to New York in September 2003, he claimed: "Personally, I don't know anybody who has died of Aids.”

And after his government had announced its massive and comprehensive plan to provide care and treatment for its citizens with HIV/AIDS, he continued to shy away from any discussion of it.

About a year ago (February 8, 2004), when interviewers from the South African Broadcasting Corporation asked Mbeki directly about AIDS, he changed the subject to focus on the lack of reliable mortality statistics in the country. “We do not know what [kills] South Africans,” he said. He suggested that serious health problems such as diabetes and tuberculosis were perhaps being overshadowed by HIV/AIDS. He said that to remedy this: “We have collected all of these notices of death from Home Affairs from 1996 to June 2003 [and] given them to… Statistics South Africa.”

Statistics South Africa (SSA) was given the task to sort out the causes of death — as recorded on death certificates. When the process was done, Mbeki said: “we will be able to get for the first time, a picture of the causes of death that will include… incidence of disease… in particular areas.”

(The entire interview can be read online).

Even though the SSA report was expected later in February 2004, it still hasn’t been released. Publication is currently expected sometime later this month. However, in the most recent report from SSA, based on a sampling of deaths for 1997–2001, the estimated proportion of deaths attributed to HIV/AIDS on the death certificate was low — at only 8.7% in 2001. This was far below the 30% predicted by mathematical models of the epidemic.

But the SSA statistics were based upon what is recorded explicitly on the death certificate. In South Africa, most people have not been tested for HIV and the HIV status of the deceased is often unknown. Also, if the medical certifier does not have access to a full medical history, the death is usually attributed to the immediate illness/condition rather than the underlying HIV infection.

According the AIDS paper, there are also other non-medical reasons why HIV is not recorded on the death certificate: “there is a strong social stigma attached to HIV/AIDS in South Africa and many patients are reluctant to reveal their HIV status and request their doctors not to do so. In addition, many funeral and life insurance policies specifically exclude cover for death from HIV/AIDS, and patient’s families may exert pressure on doctors not to certify the death as such in order to claim the benefits.”

The study

To determine whether HIV/AIDS deaths are being under-reported and produce a more accurate estimate the contribution of HIV to mortality, the MRC/UCT researchers used available cause-of-death data to estimate cause-specific mortality rates — with special attention to AIDS-associated conditions and the changing age-specific distribution of deaths — since the AIDS epidemic most greatly effects infants and sexually active adults.

The last year for which complete cause of death data are available is 1996. As the heterosexual AIDS epidemic was still relatively new to South Africa in that year, the reported rate of death due to AIDS was quite low (2.2%). Data from this year were used as a baseline in the study and compared to combined 2000-2001 data derived from the SSA 1997-2001 report. Death rates were considered up to 59 years for women and 64 years for men, based on the gender differences in the age distribution of HIV prevalence.

Researchers identified those conditions where there was a noticeable increase in mortality. When the increase followed the same age distribution pattern as the HIV deaths, a proportion of the deaths due to those conditions were deemed likely to be misclassified HIV deaths.

Results

Mortality rates in South Africa increased between 1996 and 2000–2001 “mainly a result of an increase in mortality related to HIV.” The total annual number of deaths in South Africa in 1996 was 387,784 and in 2000–2001 was estimated to be 556,585. The death rate per 1000 people increased from 9.4 to 12.4 for the respective periods.

Deaths due to HIV/AIDS, as recorded on the death certificate, followed a distinct age pattern. There was a marked increase of almost 7 per 1000 in child deaths and a peak increase of 2.7 per 1000 at age 30–34 years for women and 2.6 per 1000 at 35–39 years for men. The age pattern is consistent with the age pattern observed for HIV seroprevalence in South Africa, with an age lag between the sexes.

Eleven other reported causes of death had increases following the same distinct age pattern typical of HIV/AIDS. Nine were selected for estimating the excess death caused by AIDS, as the increase in actual numbers of deaths for two of the causes were small.

For males, these AIDS-related conditions contributed “60.2% (31 999 out of 53 185 deaths) and for females 57.8% (34 345 out of 59 445 deaths) of the total HIV-linked adult deaths. Tuberculosis and lower respiratory infections accounted for approximately 80% of the excess deaths attributed to AIDS in adult males and 70% in adult females. In children under 5 years of age, AIDS-related conditions contributed 65.6% (26,715 out of 40,724) of the total deaths from HIV infection. In contrast to adults, lower respiratory infections, diarrhoea and protein–energy malnutrition accounted for approximately 85% of the excess deaths in children.”

In other words, the actual number of deaths due to underlying HIV/AIDS was more than double what had been reported on the death certificate. This amount came quite close (93%) to what had been predicted by the models for the HIV epidemic.

Implications

The study has shown that mortality data need careful interpretation and that efforts need to be made to reduce tendencies to misclassify causes of death in the future while maintaining confidentiality of information regarding cause of death.

According to the authors, “this study highlights the importance of rapid surveillance of the age and sex profile of deaths. If death registration were complete, the effects of a severe epidemic would be reflected in a change in both the overall number and age distribution of total deaths, regardless of any misclassification of or protocol defining a death from HIV or AIDS.”