Some age-related conditions lead to poorer physical function in patients with HIV

Some age-associated illnesses are associated with poorer physical function in HIV-positive patients when compared to HIV-negative people, US investigators report in the January edition of AIDS Patient Care and STDs. 

The investigators compared physical function in HIV-positive and HIV-negative patients of the same age. Most of the study participants were aged over 50, which the investigators emphasise is “a frequently used benchmark to designate older HIV-infected adults.”

Results showed that there was a steeper annual decline in physical function among HIV-positive patients than HIV-negative individuals. However the difference was only modest – a 50-year-old HIV-positive patient had the same level of physical function as an HIV-negative individual aged 52.

Nevertheless, the investigators comment, “the magnitude of the rate of decline in function…was greater in HIV-infected patents.”

Some of the diseases common in older age were associated with poorer physical function in those with HIV.

Studies conducted before effective antiretroviral therapy was introduced showed that many patients with advanced HIV disease had poor physical function.

Although rates of serious HIV-related illnesses have fallen in recent years, there is concern that patients with HIV may have an increased risk cardiovascular disease, obstructive pulmonary disease, and low bone mineral density. In HIV-negative patients these diseases of ageing are associated with poorer physical function, which in turn is a risk factor for a higher risk of death.

Therefore investigators from the US Department of Veterans Affairs Aging Cohort Study (VACS) undertook research to compare physical function in HIV-positive and HIV-negative patients, and to see if age-related illness were associated with associated with deterioration in patients physical functioning.

 A total of 3227 HIV-positive and 3240 HIV-negative individuals were recruited to the study between 2002 and 2006. Approximately 50% of HIV-positive patients were aged 50 or above. Individuals completed questionnaires enquiring ability to attend to their day-to-day physical needs, work, and exercise.

Information was also gathered on the patients’ demographics and health, and this showed that over 80% of the HIV-positive patients were taking antiretroviral therapy and approximately 25% had a CD4 cell count above 500 cells/mm³.

There were important differences between the two groups of patients. Fewer patients with HIV were aged over 55 (27% vs. 32%) and individuals with HIV were less likely than those who were HIV-negative to have been diagnosed with heart failure, coronary heart disease, hypertension, chronic pulmonary disease, vascular disease or stroke. However, HIV-positive patients exercised less frequently, especially those aged over 55 (p = 0.05).

Overall 35% of patients reported no problems with their physical function, and better functioning was associated with greater frequency of exercise.

During the study 18% of HIV-positive patients and 7% of HIV-negative individuals died. Poor physical function almost doubled the risk of death (hazard ratio [HR] = 1.96; 95% confidence interval [CI], 1.60-2.39).

After taking into consideration demographic differences and clinical factors such as the presence of co-morbid conditions, the investigators found that physical function was significantly poorer in patients with HIV (p = 0.02).

When HIV-positive and HIV-negative individuals were compared, those with HIV had a greater annual decline in physical function.

Comparison by age group showed that younger HIV-positive patients (under 44) had better physical function than HIV-negative individuals (p < 0.01). But this was reverse for those aged over 55 (p < 0.01).

Further analysis showed that the average 50-year-old HIV-positive patient has the same level of physical function as an HIV-negative individual aged 51.5 year.

Cardiovascular disease and hypertension was associated with similar declines in physical function for both HIV-positive and HIV-negative patients.

For patients with chronic obstructive pulmonary disease, infection with HIV was associated with poorer functioning. “A 50-year old HIV-infected subject had the equivalent level of function as a 68.1-year old uninfected subject.”

The investigators suggest that this could be because of accelerated disease progression or longer duration of illness in patients with HIV. “The results support an aging interaction driven by comorbidity that warrants further investigation,” comment the investigators.

They also believe the relationship between chromic pulmonary disease and poorer physical function had implications fort the care of HIV-positive patients, especially the provision of support to stop smoking.

But in some instances, HIV-positive patients had better physical functioning. These included diabetes. A 50-year-old HIV-positive patient with this condition had the same level of physical function as a 36-year-old HIV-negative diabetic patient.

"The majority of HIV-infected VACS participants receive combination antiretroviral therapy and have high CD4 cell counts,” write the investigators, “our findings demonstrate that age-related comorbidity should be considered an important risk factor for poor physical function in this setting.” They conclude, “the study supports further integration of primary health care and provision into HIV care with increased focus on age-associated comorbidity.”