How Should We Monitor for TDF-Related Nephrotoxicity?

Tenofovir disoproxil fumarate (TDF) can cause proximal renal tubular injury. Because dipstick urinalysis primarily detects albumin, “tubular proteinuria” — which often involves nonalbumin proteins — may escape notice. To assess the pattern of proteinuria in patients with TDF-related nephrotoxicity, investigators performed a retrospective chart review of all biopsy-confirmed cases identified between January 2001 and April 2014 at one New York center (N=43).

At the time of kidney biopsy, the median duration of TDF therapy was 9.5 months and the median serum creatinine level was 4.9 mg/dL. Of the 37 patients who had a dipstick urinalysis, 40% had ≤1+ proteinuria. In the 27 patients who had urine total protein quantified by 24-hour collection or…