Jennifer O. Lam, PhD, of Kaiser Permanente Northern California, and colleagues culled through medical records of Kaiser members in California, Maryland, Virginia and Washington, DC, to identify 13,296 people living with HIV. These participants were matched by age, sex and race with 155,354 HIV-negative Kaiser members. All participants were older than 50, and nine out of 10 were men. The median age of the men, whether living with HIV or not, was 54 years.
The HIV-positive participants had been living with the virus for nine years, on average, all were on antiretroviral medications and 80% had an undetectable viral load at baseline; 36% had a history of AIDS. People with HIV were slightly more likely to be white (53% versus 51% of HIV-negative people), and they were also more likely to have been diagnosed with substance use disorder, cardiovascular disease, depression or high cholesterol. HIV-negative people had higher rates of hypertension, diabetes and obesity.
At the beginning of the study period in 2000, people living with HIV had four times the rate of dementia, though the overall numbers were small, at 2% versus 0.5%.
Removing those people from their analysis, the researchers tracked diagnostic codes for dementia among people with and without HIV from 2000 through 2016 or until they passed away or left the Kaiser system. However, the average number of years of follow-up was nowhere near the 16 years of the study period. HIV-positive and HIV-negative people were in the Kaiser system for an average of five years and six years, respectively.
Among people who stayed in the system until 2016, 3% of people with HIV received a dementia diagnosis compared to 1% of HIV-negative people. No matter what time period they looked at, people living with HIV had higher rates of dementia. However, all dementia rates dropped over time; the decrease was especially dramatic among HIV-positive people. During 2000 to 2002, seven out of 1,000 people living with HIV received a dementia diagnosis. By 2015, that rate was three per 1,000 people—more than a twofold drop. And this is one condition where the researchers saw no disparities by race or gender.
However, HIV was still associated with an 80% increase in dementia diagnosis overall compared with HIV-negative people. The rate appeared to drop if the person had never had an AIDS-defining nadir (lowest-ever) CD4 count below 200 (a 60% increase compared with the HIV-negative group) or had an undetectable viral load at the start of the study (a 70% increase).
What’s more, the overall prevalence of dementia (meaning both new and previously existing cases) among people with HIV from 2000 to 2016 was nearly twice as high as it was for HIV-negative people, representing a 90% increase. From 2015 to 2016, the prevalence of dementia was 75% higher for people with HIV.
Lam and colleagues attributed at least some of the decrease over time to the increased potency, tolerability and simplicity of HIV treatment. But it could also be due in part to managing risk factors for dementia.
“Our observation that reductions in incident dementia were more pronounced among [people with HIV] may indicate better chronic disease management and attention to modifiable risk factors such as smoking cessation and hypertension control in this population, which typically has more frequent contact with the health care system than the average adult,” they wrote.
Click here to read the study abstract.