Low incidence of renal impairment observed in tenofovir-treated patients

Objectives: To compare the incidence of renal impairment in HIV-infected patients exposed versus unexposed to tenofovir and to characterize risk factors associated with renal impairment. Methods: We undertook a retrospective cohort and nested case-control study of 514 Northwestern University HIV Outpatient Study participants who received antiretroviral therapy (ART) between 1 August 2001 and 31 July 2007. Renal impairment was defined as meeting at least one of two validated criteria based on serum creatinine, calculated glomerular filtration rate and creatinine clearance. Multivariable analysis was performed to identify risk factors for renal impairment. Results: Renal impairment occurred in 14% (n= 72 ) of the cohort and was not correlated with exposure to tenofovir in univariate analyses. In multivariable analysis, more advanced age [odds ratio (OR)= 1 . 04 , P=0.02], diabetes (OR = 3.6, P<0.01), decreased weight (OR=0.97, P= 0 . 02 ) and endpoint CD4 ≤200 cells/mm 3 (OR = 2.5, P=0. 03 ) were positive predictors of renal impairment; tenofovir exposure (OR = 0.41, P= 0 . 01 ) was negatively correlated with renal impairment. Conclusions: Tenofovir-containing ART was associated with less renal impairment than ART without tenofovir in a patient cohort with a high incidence of renal impairment. Chronic co-morbid conditions known to be associated with renal impairment should be excluded prior to attributing renal impairment to tenofovir.