HIV Weekly - 5th September 2012

Kidney stones

The ritonavir-boosted protease inhibitor atazanavir (Reyataz) is more likely to cause kidney stones than other ritonavir-boosted protease inhibitors, new research shows.

Overall, HIV treatment reduces the risk of kidney disease. However, some anti-HIV drugs can affect kidney function and others can cause kidney stones.

Kidney stones are stone-like lumps that can develop in one or both of the kidneys. Waste products in the blood can form into tiny crystals in the kidneys, which can then bond together to become stones. These can cause severe pain in the abdomen, groin and urinary tract.

Atazanavir/ritonavir is a powerful anti-HIV drug and causes only mild side-effects. Atazanavir belongs to a class of anti-HIV drugs known as protease inhibitors. These drugs are often taken with a small dose of another drug, called ritonavir, which slows down how quickly they are processed in the body and therefore ‘boosts’ levels in the blood.

But researchers in Japan were aware of reports that atazanavir may cause kidney stones. They wanted to investigate this further. They therefore monitored 1240 people who started HIV treatment combinations based on a ritonavir-boosted protease inhibitor between 2004 and 2010.

A total of 35 people developed kidney stones; 31 of these were taking atazanavir.

Overall, 7% of the people treated with atazanavir developed a stone, compared to 0.5% of those taking one of the other protease inhibitors.

The researchers calculated that people treated with atazanavir were ten times more likely to develop kidney stones.

They recommend that treatment with atazanavir should be stopped if someone develops a stone. This is because kidney stones often recurred.

There’s more information on HIV & the kidneys in this feature article from the HIV Treatment Update archive.

HIV and hepatitis C

New cases of hepatitis C among HIV-positive gay men in Switzerland have increased by a factor of 18 since 1998.

Epidemics of sexually transmitted hepatitis C have been identified among HIV-positive gay men in many European countries, including the UK. Liver disease caused by hepatitis C is now a leading cause of serious illness and death in people who are co-infected with HIV and hepatitis C.

Doctors in Switzerland looked at rates of new hepatitis C infections in three groups of people with HIV: gay men; injecting drug users; and heterosexual men and women. Initially they looked at a group of 12,000 people.

In 1998, 3% of gay men were co-infected with hepatitis C, as were 92% of injecting drug users and 11% of heterosexuals.

The next stage of their analysis involved over 3300 gay men, over 3000 heterosexual men and women and 123 injecting drug users. Over the next eleven years, a further 3% of gay men became infected with hepatitis C, as did one-third of injecting drugs users and 1% of heterosexuals.

The rate of new infections fell in injecting drug users and remained steady in heterosexuals.

In contrast, incidence of hepatitis C increased massively in gay men. Of the 101 new hepatitis C infections seen in this group, 51 occurred between 2008 and 2011.

There was clear evidence that the infection was being sexually transmitted in gay men. It was associated with not using a condom and recent diagnosis with syphilis.

For more news, resources and features, visit our hepatitis C topics page.

Drug-resistant tuberculosis

International research shows that 7% of people taking second-line treatment for tuberculosis (TB) have extensively drug-resistant (XDR) TB.

TB is an important cause of serious illness and death in people with HIV.

Treatment with a combination of antibiotics can cure TB.

However, the infection can become resistant to the drugs used to treat it.

TB with resistance to the two important first-line drugs isoniazid and rifampicin is called multidrug-resistant TB (MDR-TB). If the infection is also resistant to two types of key second-line drugs it is classified as XDR-TB. Some of the outbreaks of XDR-TB have involved HIV-positive people. It can be very difficult to cure and, unlike drug-sensitive TB, has a high mortality rate.

The latest research involved 1278 people with MDR-TB in eight countries with serious TB epidemics.

Tests showed that 44% of people in the study were also resistant to at least one second-line drug and that 7% had XDR-TB (resistance to an injectable drug and a fluoroquinolone).  

“These results show that XDR tuberculosis is increasingly a cause for concern,” comment the researchers.

For more information on HIV and TB in resource-limited settings, visit the web pages of our regular e-bulletin HIV & AIDS Treatment in Practice (HATIP). For information on HIV and TB in the UK, you may find our HIV & TB booklet helpful.