HIV treatment – factors affecting treatment outcomes

Researchers in the US have found that the immune systems of  people aged 50 and over recover less well than those in younger people once they start HIV treatment. They recommend that earlier treatment should be a priority in this group.

The study looked at a range of factors associated with longer-term outcomes of HIV treatment. Researchers thought that age, people’s health before starting treatment, and CD4 count and viral load during the first five years of treatment, would affect responses in the longer term.

Researchers looked at the response to treatment in 614 men who had been on treatment for five to twelve years.

In the first five years of treatment, all the participants had significant increases in their CD4 count, whatever it had been on starting treatment. But people whose CD4 count was under 350 on starting treatment had poorer increases, as did people who were co-infected with hepatitis B.

People who had an undetectable viral load for at least half of the first five years on treatment had higher CD4 cell counts in the longer term, as did those individuals who stayed on their first or second combination of drugs.

Age at starting treatment seems to predict longer-term outcomes: average CD4 counts were lower in men who started treatment aged 50 or over, compared to people who started under 40. To achieve a similar long-term CD4 cell count as the under 40s, older patients would have needed to start treatment when their CD4 cell count was above 350 cells/mm³.

People who had taken all their treatment exactly as prescribed (often called adherence) did well on treatment.

Encouragingly, even with variations in outcomes, the findings of the study show that HIV treatment works well in the longer term. The majority of people had a CD4 cell count above 500 cells/mm³ after five or more years of treatment and 75% of them had an undetectable viral load.

HIV and health monitoring – CD8 cell count

New research shows that a high CD8 cell count is associated with poorer HIV treatment outcomes.

CD8 cells are immune system cells. They play an important part in controlling untreated HIV infection. However, in people not taking HIV treatment, an elevated count has been associated with faster disease progression.

Researchers from the US military wanted to see if a high CD8 cell count was also associated with HIV treatment outcomes.

They monitored 817 patients who started HIV therapy between 1996 and 2008. A CD8 cell count above 1200 was regarded as elevated.

All the patients had an undetectable viral load one year after starting treatment, and during this time, average CD8 cell count fell by 61.

But in the longer term, a higher CD8 cell count was associated with poorer outcomes, especially for patients who started HIV treatment after 2000.

Average CD8 cell count increased in patients whose viral load became detectable, but fell among patients who maintained an undetectable viral load.

“We found that elevated total CD8 cell counts were associated with greater risk of future virologic failure,” comment the researchers.

They believe their findings have significance for routine HIV care, commenting: “An elevated CD8 count may be one of the few indicators of future virologic failure among virally suppressed individuals who may not otherwise be viewed as at high risk of failure.” 

HIV and vitamin D levels

Maintaining adequate levels of vitamin D is important to the general health of people with HIV, new research shows.

Low levels of vitamin D were associated with some significant health problems seen in patients with HIV.

Earlier research has shown that many patients with HIV have low levels of vitamin D, and studies conducted in the general population have established a link between vitamin D deficiency and an increased risk of cardiovascular disease.

Doctors therefore wanted to see if levels of the vitamin were associated with markers of inflammation in patients with HIV, as well as an important early warning sign of cardiovascular disease, and CD4 cell count.

Overall, the 149 HIV-positive people enrolled in the study had significantly lower vitamin D levels than those who were HIV-negative.

In the patients with HIV, low levels of the vitamin were associated with increased inflammation, a lower CD4 cell count, and thickening of the carotid artery – an important early warning sign of hardening of the arteries, a major risk factor for cardiovascular disease.

Some HIV clinics now monitor vitamin D as part of routine care and your doctor may prescribe supplements to help boost levels of the vitamin, if necessary.

HIV and sexual health – superinfection

Dutch researchers have failed to find any evidence of HIV superinfection in HIV-infected gay men who had unprotected sex.

Superinfection (often called reinfection) involves infection with a second strain of HIV. Risk factors for superinfection appear to be the same as those for initial infection with HIV, especially unprotected anal or vaginal sex.

Many HIV-positive people choose to have unprotected sex with other people with HIV – this is often called serosorting.

About 50 cases have been reported in the medical literature. However, there’s disagreement about how common it really is. Some researchers think it is very rare, but others believe much more common than the small number of case reports suggests.

Researchers in Amsterdam wanted to gain a better understanding of this important question.

The research involved 15 HIV-positive gay men. They had blood tests every three months to check for superinfection. Every six months they were asked if they had had unprotected anal sex, or if they had been diagnosed with a sexually transmitted infection (STI).

All the men had either reported unprotected anal sex with two or more partners, or were diagnosed with a STI, in at least one six-month period.    

The men were monitored for an average of 5.8 years.

No superinfections were detected.

However, the researchers do not regard their results as definitive and call for further studies into this matter. In particular, they speculate that the level of risk of the men in their study may not have been high enough to lead to superinfection.

But the research envisaged by the researchers may be difficult to conduct, especially because of the criminalisation of HIV transmission, or of non-disclosure of infection status, in many countries.

This means that men may be disinclined to provide frank information about their sexual behaviour, even where the inquiry relates to sexual behaviour with partners of the same HIV status.

HIV and hepatitis C

Researchers have found that a gene is associated with an increased risk of liver cirrhosis (permanent scarring of the liver) in patients co-infected with HIV and hepatitis C.

The gene – called IL28B gene – was the single biggest risk factor for cirrhosis, possibly explained by its association with long-term disturbances in liver function.

The study involved 304 co-infected patients. In all, 46% of patients carried the gene. It was associated with a lower CD4 cell count, and poorer liver function. Moreover, it was also the single most important risk factor for liver cirrhosis.

Despite this, the same gene has been associated with an improved response to hepatitis C therapy in co-infected patients.

Monitoring for the gene could help identify patients who’d especially benefit from hepatitis C treatment.