1. Department of Internal Medicine, Botucatu Medical School, São Paulo State University (UNESP), Botucatu 18618-687, Brazil
2. Laboratory of Medical Investigation (LIM-29), Division of Nephrology, University of São Paulo Medical School, São Paulo 01246-903, Brazil
3. Department of Biostatistics, Institute of Biosciences, São Paulo State University (UNESP), Botucatu 18618-689, Brazil