Evaluation of renal function in sickle cell disease patients in Brazil

The objective of this study was to investigate renal function in a cohort of 98 patients with sickle cell disease (SCD) followed up at a tertiary hospital in Brazil. Clinical and laboratory characteristics at the time of the most recent medical examination were analyzed. Renal function was evaluated by the estimation of glomerular filtration rate (GFR) by the criteria of the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI). We compared patients with normal GFR to patients with decreased GFR (<60 mL.min(-1.) (1.73 m(2))(-1)) and hyperfiltration (>120 mL.min(-1.)(1.73 m(2))(-1)). Comparison between patients according to the use of hydroxyurea and comparison of clinical and laboratory parameters according to GFR were also carried out. Average patient age was 33.8 +/- 13.3 years (range 19-67 years), and 57 (58.1%) patients were females. The comparison of patients according to GFR showed that patients with decreased GFR (< 60 mL.min(-1.)(1.73 m(2))(-1)) were older, had lower levels of hematocrit, hemoglobin and platelets and higher levels of urea and creatinine. Independent risk factors for decreased GFR were advanced age (OR = 21.6, P < 0.0001) and anemia (OR = 39.6, P < 0.0001). Patients with glomerular hyperfiltration tended to be younger, had higher levels of hematocrit, hemoglobin and platelets and lower levels of urea and creatinine, with less frequent urinary abnormalities. Hydroxyurea, at the dosage of 500-1000 mg/day, was being administered to 28.5% of the patients, and there was no significant difference regarding renal function between the two groups. Further studies are required to establish the best therapeutic approach to renal abnormalities in SCD.