People with HIV who are treated with Viread (tenofovir disoproxil fumarate), in particular if they are also on Norvir (ritonavir) as a booster for protease inhibitors, should undergo regular monitoring to detect a form of acute injury to the organ known as Fanconi syndrome, aidsmap reports.

Fanconi syndrome is a form of kidney failure brought on by substances leaking out of the blood and into the urine that should ordinarily be reabsorbed into the bloodstream. These include phosphates, amino acids and bicarbonate.

Viread is included in Truvada (tenofovir disoproxil fumarate/emtricitabine), Atripla (efavirenz/tenofovir/emtricitabine), Complera (rilpivirine/tenofovir/emtricitabine) and Stribild (elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate).

Australian researchers conducted a study of 1,044 people with HIV who began antiretroviral (ARV) treatment with Viread between 2002 and 2016; 398 of them also took Norvir.

Findings were presented at the 9th International AIDS Society Conference on HIV Science in Paris (IAS 2017).

The average age of cohort members was 38 (those taking Norvir were 41 years old on average). A total of 88.5 percent of them were male, and 75 percent were gay men. They took Viread for 3.5 years on average, four years if they were also on Norvir.

The average eGFR, an indication of kidney health, when the individuals started taking Viread was normal, at 106. A total of 2.5 percent of the cohort and 1.6 percent of those on Norvir had kidney malfunction at this point, defined by an eGFR below 50.

Thirteen people (1.25 percent) developed Fanconi syndrome during the study, for an annual rate of 0.11 percent. These individuals spent an average 5.5 years on Viread before developing the syndrome.

Those who developed the syndrome had no major warning signs; they otherwise seemed to have good kidney health during the time leading up to developing the acute condition. A diagnosis of the syndrome was not associated with age, sex, high blood pressure or lipid levels, diabetes, viral hepatitis, low CD4 count or lowest-ever CD4 count or initial eGFR before starting Viread.

Nine of those who developed Fanconi syndrome were taking Norvir in addition to Viread. This group had a diagnosis rate of 0.55 percent per year. The researchers found that taking Norvir in addition to Viread was associated with a 4.71-fold increased risk of developing the syndrome.

The researchers recommended an inexpensive urine dipstick test at each HIV checkup to monitor for Fanconi syndrome.

To read the aidsmap article, click here.

To read the conference abstract, click here.

To read the conference poster, click here.

To view a webcast of the conference presentation, click here.