Estimating glomerular filtration rate in HIV-infected adults in Africa: comparison of Cockcroft-Gault and Modification of Diet in Renal Disease formulae.

BACKGROUND: Cockcroft-Gault (CG) and Modification of Diet in Renal Disease (MDRD) formulae are recommended for glomerular filtration rate (GFR) estimation, but neither has been validated or directly compared longitudinally in HIV-infected patients or in Africa. METHODS: We investigated differences between formulae in baseline GFR, GFR changes and incidence of impaired GFR after initiation of antiretroviral therapy (ART) in 3,316 HIV-infected adults in Africa, considering sex, age, body mass index and baseline laboratory parameters as predictors. RESULTS: Participants were 65% women, median age 36.8 years, median weight 56.7 kg. Baseline GFR was lower using CG (median 89 ml/min/1.73 m2, 7.4% <60 ml/min/1.73 m2) versus MDRD (103 ml/min/1.73 m2, 3.1% <60 ml/min/1.73 m2). At 36 weeks, median CG-GFR increased (92 ml/min/1.73 m2), whereas MDRD-GFR decreased (96 ml/min/1.73 m2). Weight (explicitly a factor in CG only) concurrently increased to 62.0 kg. GFR changes from weeks 36-96 (after weight stabilization) were similar across formulae. By 96 weeks, 56 patients developed severe GFR impairment (