Department of Research & Evaluation News

A study reviewing 16 years of patient data found nearly double the rate of dementia among people with HIV compared with those without HIV. The rate of dementia decreased over time for both groups but remained higher for those with HIV, reported research published in the journal AIDS.

The study compared more than 13,000 people with HIV, ages 50 and older and being treated with antiretroviral therapy (ART), with more than 154,000 people without HIV who were similar by gender, age, and race or ethnicity. Over the study period 2.5% of the people with HIV were diagnosed with dementia, compared with 1.3% of people without HIV.

“People with HIV are getting older and aging-related conditions like dementia are becoming more common,” said lead author Jennifer Lam, PhD, a staff scientist with the Kaiser Permanente Northern California Division of Research. “It will be important to better understand factors that may be contributing to persistently elevated dementia risk among ART-treated people with HIV.”

Among older U.S. adults, the incidence of dementias such as Alzheimer’s disease has decreased in recent years, possibly because of improvements in cardiovascular care. The researchers wanted to find out if a similar trend existed among people living with HIV and on ART as they reach ages when dementia risk increases.

Study participants were members of Kaiser Permanente in Northern California, Southern California, and the Mid-Atlantic States between 2000 and 2016. The study included 13,047 people with HIV; they were 89% male, 53% white, 20% Black, 17% Hispanic and 10% Asian or other race/ethnicity. The medical records analysis covered a total of 16 years with the average patient’s history followed for 5.4 years.

The analysis found that over time, the incidence of dementia decreased on average 8% every 2 years for people with HIV and 3% among those without HIV. However, actual risk of developing dementia remained higher for people with HIV.

“While the improvements are encouraging, there is still work to do given the persistently higher risk of dementia in this high-risk population,” said senior author Michael Silverberg, PhD, MPH, a research scientist with the Division of Research.

The authors said that reductions in dementia among people with HIV could be related to improvements in HIV treatment, better chronic disease management, and efforts to encourage smoking cessation and blood pressure control.

“As our HIV patients live longer and grow older as a result of successful HIV treatment, diseases of aging like dementia are increasingly playing an important role,” said co-author William Towner, MD, of the Kaiser Permanente Southern California Department of Research & Evaluation. “For those of us who are frontline clinicians, research like this shows us we must be attuned to these illnesses to best care for our elderly patients.”

Increased risk for people with HIV

Lam said there are several potential reasons for the increased dementia risk in people with HIV that future research can explore: length of HIV infection, type of HIV medication, HIV-related inflammation, or biological effects of the virus that ART cannot address.

When comparing dementia by HIV status, the researchers took into account well-known risk factors for dementia, including sociodemographics, substance use, and cardiovascular disease. They also controlled for the frequency of health care utilization. But the elevated risk of dementia among people with HIV remained, ranging from 1.2 to 3.7 times higher over the course of the 16-year study period.

Co-author Craig E. Hou, MD, a neurologist with The Permanente Medical Group, said the findings provide important questions for further study but that the current clinical advice remains the same.

“Emerging data is confirming the higher risk of dementia in people with HIV. But the field does not yet know why that is or what is causing the higher risk,” Hou said. “Therefore, advice regarding cognitive and brain health remains general and applicable to all people. We encourage people to eat a heart-healthy diet, stay physically active and engage in ongoing intellectual and mental activity.”

Lam said the research team will continue to study the topic, starting with a more in-depth analysis of HIV-related and non-HIV-related risk factors for dementia, as well as how other aging-related conditions may influence dementia risk in people with HIV.

The research was funded by grants from the Kaiser Permanente Northern California Community Benefit Grants Program and the National Institute of Allergy and Infectious Diseases.

Co-authors also included Catherine Lee, PhD, Paola Gilsanz, ScD, Wendy A. Leyden, MPH, and Derek Satre PhD, of the Kaiser Permanente Northern California Division of Research; Jason A. Flamm, MD, of Kaiser Permanente Sacramento; William J. Towner, MD, of Kaiser Permanente Southern California Department of Research & Evaluation; and Michael A. Horberg, MD, of the Mid-Atlantic Permanente Research Institute.