Factors Associated with ICU Admission and In-Hospital Mortality in a Decade of HIV/AIDS Admissions to a Tertiary Hospital at the Epicenter of the Brazilian Epidemic (2015-2024)

Imagine the human body as a bustling city. Inside, a dedicated security force called the immune system patrols the streets, keeping out invaders like bacteria and viruses. When HIV enters the city, it's like a saboteur that slowly dismantles the security headquarters. Over time, if the saboteur isn't stopped, the city becomes vulnerable. Without its guards, even common neighborhood nuisances—like a simple cold or a minor cut—can turn into life-threatening disasters. This is the world of HIV and "opportunistic infections" (OIs): illnesses that usually wouldn't bother a healthy person but strike hard when the immune system is down.

Doctors have a special tool called antiretroviral therapy (ART), which acts like a repair crew, fixing the security headquarters and stopping the saboteur. In many places, this repair crew is free and easy to access. However, in some corners of the world, people don't know they have the saboteur until the city is already in chaos. This study dives into a specific, troubled neighborhood: the southern region of Brazil, particularly the city of Porto Alegre. Here, the epidemic looks different than in other parts of the country, affecting a mix of people in unique ways. The big question researchers asked was: "In this specific city, over the last decade, who is ending up in the hospital, why are they getting so sick, and what pushes them toward the most critical moments of their illness?"

---

The Ten-Year Hospital Snapshot

To answer these questions, a team of researchers from UCLA and local hospitals in Brazil took a giant magnifying glass to ten years of hospital records, from 2015 to 2024. They looked at nearly 5,200 hospital admissions for infectious diseases and found that a massive chunk—about 69%—were due to HIV. That's roughly 3,600 admissions involving nearly 2,400 different people.

The researchers were looking for "Severe Outcomes" (SO). Think of this as the "red alert" level in the hospital. A patient hit the red alert if they had to go to the Intensive Care Unit (ICU) or if they passed away while still in the hospital. They wanted to know what factors were like the "tipping point" that pushed a patient into this dangerous zone.

Who is in the Hospital?

The picture of the patients changed over the decade. In 2015, the average patient was 41 years old; by 2024, that average crept up to 44. The hospital population was mostly white (65%) and male (53%), but there was a significant shift: more women were being admitted over time. By 2022, women made up 57% of all HIV admissions and a whopping 61% of those with "Advanced HIV Disease" (AHD).

Speaking of AHD, this is a crucial concept. The researchers defined AHD as patients whose immune systems were in a state of severe collapse (specifically, World Health Organization Stage III or IV). About 65% of the patients in this study were in this advanced stage. Shockingly, among these advanced cases, 77% hadn't even finished high school, and 21% of all admitted patients were being diagnosed with HIV for the very first time right as they walked through the hospital doors.

The "Red Alert" Triggers

So, what made the difference between a patient recovering on a regular ward and one ending up in the ICU or dying? The study found that certain conditions were like heavy anchors dragging patients down.

If a patient walked in with a brand-new HIV diagnosis, or if their immune system was so weak they had fewer than 50 security guards (CD4 cells) per square millimeter of blood, their risk of a severe outcome skyrocketed. Specific infections were also major troublemakers. If a patient had sepsis (a body-wide reaction to infection), bacterial pneumonia, tuberculosis, or a specific lung infection called pneumocystis pneumonia, they were much more likely to face a severe outcome.

Interestingly, the study found that a common infection called esophageal candidiasis (a yeast infection in the throat) actually seemed to be a "protective" factor. This doesn't mean the infection is good; rather, it suggests that patients with this specific infection might be caught slightly earlier in the disease process or have a different clinical profile that keeps them out of the ICU compared to those with the more aggressive infections listed above.

The Role of Time and Change

The study also looked at how the situation changed over the decade. After the COVID-19 pandemic hit in 2020, the total number of HIV hospitalizations dropped by about 31%. This makes sense; when a city is fighting a massive new virus, resources get stretched, and people might avoid hospitals for other issues.

However, the researchers noticed something worrying. Even though fewer people were coming to the hospital overall, the proportion of patients with advanced disease and new HIV diagnoses didn't really go down. The "red alert" triggers were still there. The case fatality rate (the percentage of patients who died in the hospital) for those with advanced disease stayed stubbornly high at 11% throughout the decade. It didn't improve, even as time went on.

The "Why" Behind the Story

The researchers pieced together a narrative: In southern Brazil, the HIV epidemic is being driven by late diagnoses. Many people aren't getting tested until they are already very sick. Once they are sick enough to be hospitalized, they are often already in the "Advanced HIV Disease" stage, fighting multiple infections at once.

The study also highlighted a shift in demographics. While men still get diagnosed with HIV more often when they first walk into the hospital, women are increasingly the ones ending up in the hospital with advanced disease. This suggests that women might be getting diagnosed earlier (before they are critically ill) but then struggling to stay connected to the care system, eventually leading to severe outcomes later.

The Bottom Line

This paper doesn't claim to have solved the problem, but it shines a bright light on where the cracks are. It suggests that in this region, the main drivers of death and critical care admission are late diagnosis and barriers to staying in care. The "red alert" isn't just about the virus itself; it's about the infections that take advantage of a weakened immune system, like tuberculosis and bacterial pneumonia, and the fact that many patients are only found when it's almost too late.

The authors conclude that to stop the bleeding, efforts need to shift. We need to find people earlier, before their immune systems collapse, and make sure they stick with their treatment. If we can catch the saboteur before it tears down the security headquarters, we might be able to keep the city safe without ever needing to call the ICU.