Tenofovir and kidney disease
A large study has found evidence that treatment with tenofovir (Viread, also in Truvada, Atripla and Eviplera) is associated with a moderately increased risk of kidney disease.
The US study involved over 10,000 people, approximately 40% of whom were treated with a combination of drugs that included tenofovir.
Results of the study showed that people who took tenofovir were more likely to develop three key markers of kidney disease.
There was also some evidence of an increased risk of kidney disease even after they had stopped taking the drug.
Tenofovir is a widely used drug and has a powerful, durable anti-HIV effect. It doesn’t cause the severe side-effects associated with some older anti-HIV drugs. Earlier studies looking at tenofovir’s impact on kidney function have produced conflicting results.
Despite showing that people taking tenofovir were more likely to develop kidney disease, the latest study didn’t quantify the absolute risk of this occurring.
It is important to bear in mind that studies consistently show that kidney problems develop in fewer than one in 20 people who take the drug, and serious impairment has been seen in fewer than one in 100. The classic risk factors, such as diabetes, high blood pressure and untreated HIV infection, continue to be more important causes of chronic kidney disease in people living with HIV. Just like anyone else, people with HIV are also vulnerable to acute kidney injury due to inflammation, infection or medications that can damage the kidneys.
Kidney function should be monitored regularly as part of routine HIV care. This means any problems can be spotted early and appropriate treatment can be provided.
Tenofovir was the only drug which increased the risk of all three markers of kidney disease investigated in the study. However, several other drugs were associated with individual aspects of kidney dysfunction. These included the drug most frequently used as an alternative to tenofovir, abacavir (Ziagen, also in Kivexa and Trizivir). This drug increased the risk of chronic kidney disease.
The investigators stress that it is important to look at their findings within the context of tenofovir’s benefits. They conclude: “Despite tenofovir’s association with progressive kidney disease, it is an important component of effective antiretroviral therapy that may be required in many patients to control viral load. The balance between its efficacy and probably adverse events requires further study.”
Safety of HIV treatment during pregnancy
However, the authors of the study stress that their findings are a starting point for further studies, and more research is needed to explore the apparent associations.
With the right treatment and care, the risk of mother-to-child transmission of HIV can be reduced to below 1%.
However, it is important to establish the safety of HIV treatment during pregnancy.
US researchers therefore looked for reports of cleft palate or lip in the babies of mothers who took HIV therapy during pregnancy.
A total of 26 cases in babies born between 2004 and 2009 were identified.
Drugs associated with this birth abnormality were efavirenz (Sustiva, also in Atripla), 3TC (Epivir), nevirapine (Viramune), Kaletra (lopinavir/ritonavir) and Combivir (3TC/AZT).
However, the researchers do not regard their findings as definitive.
They emphasise that earlier research failed to show any association between HIV treatment during pregnancy and these birth abnormalities.
In addition, their findings didn’t take into account “important confounders such as personal characteristics, diet, genetics, and so forth".
They therefore conclude, “Further studies should be performed to assess the relative safety of these drugs and the specific conditions or potential synergies that might lead to the development of cleft lip and palate."
Anal cancer
All groups of adults with HIV have an increased risk of anal cancer, a new study has shown.
The risk was highest for HIV-positive gay men, but heterosexual men and women also had an increased risk of the malignancy.
Infection with some strains of the human papillomavirus (HPV) can cause cell changes in the anus that can develop into cancer.
Researchers looked at the results of 13 US and Canadian studies examining the risk of anal cancer for people with HIV.
Results showed that HIV-positive gay men were 80 times more likely to develop anal cancer than men in the general North American population.
However, they also indicated that heterosexual HIV-positive men were 27 times more likely to develop the malignancy than men in the general population.
The cancer was also much more common in HIV-positive women than HIV-negative women.
Incidence of anal cancer peaked between 1996 and 2003. This period coincided with the introduction of effective HIV treatment.
The researchers think that this was a function of the improved prognosis of people living with HIV, which allowed long-term cell changes caused by high-risk strains of HPV to become cancerous. In contrast, the levelling of the cancer rate was put down to the beneficial effects of antiretroviral treatment on the immune system.
There is no agreement about the value of screening people with HIV for pre-cancerous anal cell changes.
However, the researchers of this study think this screening could be cost effective.
“The New York State AIDS Institute guidelines…recommend anal digital rectal examination for all patients, targeted anal cytology for MSM [men who have sex with men], for individuals with a history of anogenital warts, and for women with a history of abnormal cervical or vulvar histology.”