What 25 Years of the HIV Outpatient Study Has Shown

HIV has gone from a virtual death sentence in the 1980s and early 1990s to a chronic condition that can be well-controlled with antiretroviral therapy (ART). There may be no better catalog of the improvements in management of the disease than the multi-decade HIV Outpatient Study (HOPS), which has profiled and tracked people living with HIV (PLWH) in the US since 1993.

The study, funded by the US Centers for Disease Control and Prevention (CDC), has enrolled thousands of people with HIV in multiple locations. It provides a rare look at a cohort of people across time, highlighting shifts in disease metrics, comorbidities, death rates, demographics, and treatment protocols--valuable information as scientists work toward eradication of the disease.

A team of investigators in the Division of HIV/AIDS Prevention at the CDC, along with colleagues at medical schools and other health facilities across the country, undertook a fresh analysis of the HOPS in order to shed light on HIV’s changes over time and provide context for the direction of future research.

“The clinical epidemiology of treated HIV infection in the United States has dramatically evolved in the past 25 years,” Kate Buchacz, PhD, MPH, a senior epidemiologist at the CDC and an author of the study, told Contagion®. “Few sources of longitudinal data exist about the health of people living with HIV during this period of major improvements in ART and clinical management of HIV infection. The rich data in our large prospective cohort enable investigation of new risk factors for HIV-related complications and monitoring progress along the HIV care continuum.”

Some of the key findings of the HOPS include the characterization of new conditions in people with HIV, such as lipodystrophy and immune reconstitution inflammatory syndrome; reduced mortality thanks to earlier administration of ART; and the revelation that certain ART medications carry a risk of damage to the cardiovascular and renal systems. The study also showed that the state of patients’ immune systems has gotten a big boost over the years: In the early to mid 90s, the median CD4 T-cell count was 244 cells/mm³ versus 640 cells/mm³ in 2017.

Death rates also dropped sharply during that time period, from 121 per 1,000 person-years down to 16. The median age at death in 1994 was 39 years, compared with 54 years in 2017.

“Today, [the] majority of HOPS patients are successfully treated with ART and have suppressed HIV viral load (92% in 2017), which is important for their own health and for prevention of sexual HIV transmission to their partners,” said Buchacz. However, her report notes that race- and ethnicity-based disparities in virologic suppression remain, with African-American men and women less likely to be virologically suppressed than others.

One side effect of the huge reduction in deaths due to AIDS opportunistic infections is that HIV patients now tend to die of problems “including cardiovascular, hepatic, pulmonary, renal, neoplastic and neurologic disorders,” the authors wrote in their report. “Improvements in HIV management and survival have resulted in an older cohort of PLWH and an increased prevalence of age-related chronic comorbidities that are common in the US population. "

"The rates of most malignancies mirror or exceed those observed in the general population, due to combined effects of HIV infection, behavioral risk factors such as elevated levels of tobacco use, and possibly overall higher rates of other risks, including oncogenic viral infections," they added.

People with HIV suffer from high rates of hepatitis and appear to be at increased risk of other sexually transmitted diseases such as syphilis, chlamydia, and gonorrhea.

The team emphasized that the HOPS provides a singular opportunity to track changes and advances in the management of HIV, including emerging issues and obstacles, that can inform the way in which clinicians evaluate and treat their patients with HIV, as well as offer a roadmap toward potential therapies and, hopefully, a cure.