HIV update - 13th May 2015

For some HIV treatments, 85% adherence may be enough

The best results of HIV treatment are seen in people who take their pills as prescribed – at the right times, without missing doses and following any instructions about food. But what happens if adherence is not quite perfect? What is the impact of sometimes missing a few doses in a month?

Previously research suggested that it was necessary for people to take at least 95% of doses at the right time and in the right way to have the best chances of achieving an undetectable viral load. But those studies were done several years ago. Some modern anti-HIV drugs may not require such high levels of adherence.

In particular, efavirenz and other drugs in the non-nucleoside reverse transcriptase inhibitor (NNRTI) class have long half-lives. This means that it takes quite a long time for the body to break down the drug. As a result, even when one dose is missed, there may still be enough of the drug in the bloodstream – left over from previous doses – to prevent the replication of HIV.

This is not generally the case for other anti-HIV drugs. For example, protease inhibitors such as atazanavir and darunavir have much shorter half-lives. They are broken down quickly by the body and missed doses will have more of an impact.

(If you are unsure which types of anti-HIV drug you are taking, NAM’s Antiretroviral drug chart may help you work it out.)

The new study analyses ten years of data from around 22,000 people living with HIV in the United States. Their adherence was estimated by looking at how often they went back to the pharmacy for antiretrovirals.

For people taking a protease inhibitor, adherence above 95% was associated with the greatest chance of having an undetectable viral load. Poorer outcomes were observed even when people were taking between 90 and 94% of their doses.

But for people taking NNRTI-based therapy, an adherence level of 85% or above was associated with just as high a chance of achieving an undetectable viral load as an adherence rate of 95% or above.

If you’re taking a once-a-day treatment, then 85% adherence would mean missing around four doses a month, while 95% adherence would involve missing one or two doses a month.

The study also found that more people taking NNRTIs were able to have good adherence than people taking protease inhibitors.

Good adherence remains the single most important thing that you can do to ensure that your HIV treatment works. Almost 100% adherence is the best thing to aim for. But the study shows that if you’re taking efavirenz, rilpivirine, Atripla or another NNRTI-based regimen, then a little forgetfulness may not be the end of the world.

NAM’s booklet ‘Taking your HIV treatment’ includes information on why adherence is important, what to do if you miss a dose and practical tips to help you remember.

Some anti-HIV drugs linked to heart disease

Heart attacks, strokes and other forms of cardiovascular disease are important causes of serious illness in people living with HIV. The reasons why rates are higher than in the general population are not fully understood.

While it is partly due to higher rates of risky behaviours such as smoking, researchers also think that HIV infection and the persistent immune activation and inflammation that it causes make a difference. There’s more controversy over the role of specific anti-HIV drugs – some, but not all, studies have found that drugs such as abacavir and protease inhibitors are associated with an increased risk of a cardiovascular disease.

The latest study to address this question suggests that there is a link between specific drug combinations and heart disease. But the researchers emphasise that serious cardiovascular events remained relatively rare. They collected data on around 25,000 people for around six years each. During this time, 934 of them had a heart attack, stroke or surgical intervention for heart disease.

People taking the following drug combinations were more likely to have heart disease:

• Kivexa (abacavir + lamivudine) +  atazanavir
• Kivexa (abacavir + lamivudine) +  efavirenz
• Combivir (zidovudine + lamivudine) + atazanavir
• Combivir (zidovudine + lamivudine) + efavirenz
• Trizivir (zidovudine + abacavir + lamivudine)

The researchers say that the findings will be most relevant for people who are older or who are already at elevated risk of heart disease. This includes people who smoke, who have high blood pressure, who have high levels of cholesterol, who do not exercise much, or who have a family history of heart disease. For people in this situation, the information could help doctors choose the best HIV treatment to offer.

But in general, the main issues to consider when choosing anti-HIV drugs are how effective they are in reducing HIV viral load and whether they have side-effects, the researchers say.

A second study on cardiovascular disease examined hardening of the arteries in HIV-positive people and HIV-negative people with similar lifestyles. Over time, people living with HIV were more likely to have their arteries clogged up by fatty substances known as plaques than people without HIV. The risk was greatest for people who had a low CD4 cell count.

For more information on these topics, see NAM’s factsheets on The heart, Stroke and Cholesterol.

Not telling other people that you have HIV

It’s often taken for granted that being able to talk about your HIV status is an essential part of living well with HIV, but there is little research to prove this. In fact, a new study shows that people who choose not to talk about having HIV with other people have just as good health outcomes as other people living with HIV.

This UK study found that a significant minority of people living with HIV had not talked about their HIV status with anyone at all. This was the case for 5% of gay men, 17% of heterosexual men and 16% of women.

Moreover, 40% of gay men hadn’t talked about HIV with any members of their family, 56% of heterosexual men hadn’t discussed it with any friends, and 84% of women hadn’t disclosed to any work colleagues.

Does this matter? Is non-disclosure associated with poorer health outcomes? While a one-off quantitative survey has some limitations in terms of the insight it can give into the quality of people’s lives and relationships, its findings are reassuring.

While many of the respondents had symptoms of depression, symptoms of anxiety or problems adhering to HIV treatment, these difficulties weren’t more frequently reported by people who hadn’t disclosed to anyone. And people were just as likely to do well on HIV treatment, whether or not they discussed their HIV status.

For a range of information and advice on disclosure in different contexts, please see the topic page on our website, ‘Telling people you have HIV’ .

It’s risky to delay hepatitis C treatment

Until recently, treatment for hepatitis C always included pegylated interferon, an injection that gave many people unpleasant side-effects. Doctors often used to recommend that people delay hepatitis C treatment until they definitely needed it.

Newer treatments only involve tablets, have fewer side-effects and are much more effective. Most hepatitis C doctors and advocates think that everyone living with hepatitis C should be able to get the new drugs. But treatment is still often limited to the sickest patients due to the high cost of the drugs.

A new study shows that delaying hepatitis C treatment until a person progresses to advanced liver disease has clear drawbacks including treatment being less effective and a greater risk of cirrhosis, liver cancer and death. People who were treated early and achieved undetectable viral load did much better.

This study was one of many reported at a recent hepatitis conference in Vienna. If you’d like to read about more recent research on hepatitis C, you may be interested in the email bulletin from www.infohep.org which is also produced by NAM. You can read the latest bulletin here.