AIDS Statistics Flaws and Symptom Bias

According to Centers for Disease Control (CDC) reports, in 2010 the number of people living with acquired immune deficiency syndrome (AIDS) was a little more than half of the number of people who have been living with the human immunodeficiency virus (HIV).

But only ten years prior, in 2010, the number of people living with AIDS versus those living with HIV were the same. Essentially, more and more people continued to contract HIV, yet fewer cases lead to full-blown AIDS.

The split happened at an odd time—around 2006—over a decade after the combination antiretroviral treatments (ART) that were heralded as a decent cure. Before 2006, everyone who got HIV got AIDS, until they didn’t.

Declining Mortality Rate Came Before AZT

Despite the ineffectiveness of individual ARTs, combination ART drugs like azidothymidine (AZT) were heralded as somewhat of a cure, preventing an effective death sentence. But overall it doesn’t appear like AZT was all that transformative.

While deaths declined after it was released, the AIDS mortality rate had already been in exponential decline prior to the development of AZT.

The large drop in mortality that occurred the year of AZT’s release is confounded by the large drop in HIV/AIDS diagnoses right before following a change in the disease’s definition.

Statistics on AIDS are fraught in many ways. The definition of what constitutes an AIDS patient has changed multiple times as more knowledge of the disease has been known: once in 1987 and then in 1993 when a test for presence of the HIV virus was required, which expanded the diagnosed population considerably. Historic data also appears to be regularly updated, sometimes not in minor ways.

Comorbidities and Mortality Rates

Originally the disease was termed “junkie pneumonia” because of its prevalence among heroin users in the 1970s. It was associated with a failing immune system that was unable to fight two separate diseases: Pneumocystis carinii pneumonia and Kaposi’s sarcoma.

Comorbidities—other simultaneous diseases and symptoms identified at the time of death—could also complicate autopsies, with various studies showing a high rate of accidental death and suicide as well as liver disease among those infected with HIV.

Currently, AIDS is considered an end-stage result of HIV, which breaks down the immune system. Although there exists a segment of scientists that dispute the connection between HIV and AIDS as there exist examples of non-HIV AIDS, sometimes considered idiopathic CD4+ lymphocytopenia (ICL), wherein a patient has a weak immune system with low CD4+ readings—white blood cell counts, also called T-lymphocytes—but no HIV present.

Examples of ICL are considered rare, in 2000, the CDC data listed slightly more people living with AIDS than with HIV—something that should be impossible if a person needs to be infected with HIV to get AIDS.

Despite massive marketing campaigns and worldwide attention to the disease, HIV incidence continued unabated through the 1990s. It wasn’t until the definition of what constituted an HIV infection changed in 1993 to require testing for the virus.

While the 1993 definition showed a substantially larger population of AIDS patients than previously considered, that population would drop off substantially after 1993.

Mortality Rates in Consistent Decline

In 1995, two years after the change in definition the Food & Drug Administration (FDA) would approve AZT, which would also lead to a decline in deaths from AIDS.

While deaths attributed to HIV/AIDS declined with AZT’s approval, the mortality rate had been in steep decline since the early 1980s. As fewer and fewer people were recognized as having the disease, even fewer were dying from it as well.

The percentage of deaths from those estimated to be living with AIDS is now regularly below 1 percent, even before the advent of preventative Pre-exposure prophylaxis (PrEP) medicines like Truvada, which got FDA approval in 2012.

In 2015, Truvada was the largest drug expenditure for California’s Medicaid program at $92 million a year.

CDC’s Inclusive HIV Death Definition

While deaths trended downward for years, over the last ten years the CDC started reporting an increase of about 5,000 more deaths from HIV in their HIV reports than there were 20 years ago.

Part of that is due to the CDC no longer making a distinction between HIV infection and AIDS.

Not only do the CDC’s reports now list only deaths due to HIV infection without mention of AIDS, it includes a note that:

Deaths of persons with a diagnosis of HIV infection may be due to any cause.

That is, the patient could have died in a car crash, but they would still be marked as dying with HIV. The CDC HIV report lists 19,624 dying from the disease in 2021, although CDC’s Wonder database only lists 4,977 that year.

Few Pandemic Changes

Despite the restrictions during the pandemic, incidence of HIV diagnoses only went down slightly, and the CDC includes a note that even that small dip might be due to a lack of testing and not a lack of disease prevalence.

HIV might not be alone in this. CDC data on other sexually transmitted diseases like gonorrhea and syphilis showed no significant change from the pandemic despite the limited amount of human interaction at the time.

U.K. Deaths More Than Diagnoses

Data in the U.K. may not make any more sense. In that country, somehow more people consistently die annually from AIDS than there are yearly AIDS diagnoses.

Potentially this could be a result of including all deaths with an HIV diagnosis independent of a cause of death, like the CDC currently does.

The British have also seen HIV diagnoses go up in 2021 following the pandemic after years and years of declines.

Incidence/Prevalence Confusion and Symptom Bias

A large complication in tracking HIV/AIDS, or any disease for that matter, is understanding the distinction between incidence and prevalence.

This was also an issue in the earlier period of the COVID-19 pandemic, previously reported by Investigative Economics. Media stories would report on the exponential growth in confirmed cases of COVID-19, or total incidence, adding to the panic that the disease was increasingly rampant.

But much of that was due to increased testing. The rate of those testing positive out of all those tested—i.e. the prevalence—was relatively consistent at around 14 percent.

Another bias in disease reporting is that most disease surveillance only happens when people visit a hospital or doctor because they are sick and are needing treatment not available from an over-the-counter medication.

Those not suffering any major symptoms are unlikely to be tested unless at-home tests are available, like there are now for COVID.

This symptom bias is almost like an inverse of the survivor bias—when data is taken only from those who survive an event and not from those who didn’t. It leads to skewed data that shows more severe symptoms for those testing positive for the disease, making the disease seem more deadly than it might be. People who show no signs of symptoms don’t get tested.

With AIDS, the high mortality rate of around 40 to 50 percent in the early 1980s could be a relic of symptom bias. The HIV antibody test wasn’t invented until 1985. Diagnosis for the disease back then largely happened when someone came to an emergency room with life-threatening conditions of pneumonia or Kaposi’s sarcoma.