GSTM1 and kidney disorder: KDQOL-36TM: Kidney Disease and Quality of Life Instrument (RAND Corporation, Santa Monica, CA); r: Spearman’s Correlation coefficient; CK: Creatinine Kinase; ALP: Alkaline Phosphatase; PTH: Parathormone; AST: Aspartate Transaminase; ALT: Alanine Transaminase; CRP: C-reactive protein; WBC: white blood cells; Hb: Hemoglobin; Ht: Hematocrit; MCV: Mean corpuscular volume.