March 20, 2009

Kidney Tube Dysfunction in Tenofovir Users

Tenofovir (found in Viread, Truvada and Atripla) is associated with an increased risk for kidney tube dysfunction in people with HIV, notably as they age, according to a study published in the March 27 issue of AIDS. People with damaged kidney tubes can ultimately have problems not only with their kidneys, but also with bone mineral absorption.

Because tenofovir is chemically similar to other drugs known to cause kidney toxicity, researchers have carefully searched for signs of kidney trouble in people taking the drug. Some people on tenofovir have developed severe kidney problems, but these cases are very rare. Dysfunction of the tubes within the kidney—responsible for transporting chemicals from the blood to urine—has also been a concern with tenofovir and has been documented in various studies.

To further explore whether tenofovir is associated with tubular dysfunction, Pablo Labarga, MD, PhD, from the Infectious Disease Department at the Hospital Carlos III in Madrid, and his colleagues conducted blood tests of 283 people living with HIV. Of those patients, 153 were on antiretroviral (ARV) therapy that included tenofovir, 49 were on ARV therapy and had no history of tenofovir use, and 81 had never taken ARVs. The patients were similar in most factors that are associated with kidney function, except that those not on ARVs were younger and people taking tenofovir had a higher body weight than the rest and were more likely to be infected with hepatitis C virus (HCV) or hepatitis B virus (HBV).

Labarga’s team found that 22 percent of those on tenofovir had tubular dysfunction, as did 6 percent of those taking ARV drugs without tenofovir and 12 percent of those with no history of ARV use. After accounting for all other factors, the risks that remained significant predictors of tubular dysfunction were tenofovir and older age.

Though the authors did not find that tubular dysfunction was associated with other kidney toxicity, they are urging health care providers to closely monitor kidney function and bone mineral levels in people taking tenofovir. This is because more people with HIV are entering their 50s and 60s and because tubular dysfunction may further increase the risk of low bone mineral density—osteopenia and osteoporosis—over longer periods of time.

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Previous Comments:

Paul C, Boston, 2009-07-12 11:37:13
I am 60 and on tenofovir (in Truvada) and have sudden onset hypertension (160/110)after being on Truvada for 6 years. My MD has chosen to treat me for pulmonary hypertension, but I suspect this could also be related to hypokalemia (low potassium) from kidney effects of tenofovir. My MD did not even raise this issue. Just prescribed an anti-hypertensive which not showing very immediate relief. I think it would make sense to drop Truvada in older, longterm HAART takers.

Bradley Huston, Gardena, CA. 90247, 2009-03-25 12:55:30
I am suffering fom abnormal kidney funtion and osteoporosis, this condition only began after I started HIV meds. The people at the clinic I attend do not seem to really concern themselves with my overall health, they are only cocerned with lowering my viral load. I find this kind of treatment offensive, they have no compassion. The drug companies do not seek to cure but only make money, chemo therepy is no cure for cancer or AIDS, yet makes the Pharmaceutical Corporations and Government rich.

Tim Horn, AIDSmeds.com, New York, NY, 2009-03-24 20:06:37
Dr. Fitzgibbons - Please know that the authors of this study did not specify type(s) of tubular damage in the patients and widely used terms like "dysfunction" and "impairment" without further clarification. This catch-all term applied to anyone with at least two altered serum or urine parameters, with at least one of them being nondiabetic glucosuria, reduced tubular resorption of phosphorous or pathologic aminoaciduria.

Jeffinprov, Providence, 2009-03-24 11:52:39
I am deeply concerned that Tenofovir continues to be prescribed and used as broadly as all appearances indicate. It was a critical factor in sending me into renal failure and the ICU two years ago, and I count myself fortunate (a.) to have survived at all and (b.) to have avoided dialysis -- the latter to the great surprise of my medical providers. This has been an unpleasant ride, and I would fear for anyone who had less access to extensive care than I.

S. Fitzgibbons MD, Houston, 2009-03-24 11:18:49
I could not figure out from your story whether you meant renal tubular acidosis, acute tubular necrosis (which may require dialysis) or just some relatively minor leak in the filtering system. "Tubular dysfunction" is so vague as to be meaningless, and a doctor who is asked about it will think they got it from some unreliable source and disregard it. Please use the technical term and explain what it means and how to test for it.