Renal disease in adult Nigerians with sickle cell anemia: a report of prevalence, clinical features and risk factors.

Renal abnormalities in adult Nigerians with sickle cell anemia (SCA) have not been extensively studied. To determine the prevalence, pattern and the associated risk factors of renal disease, 72 subjects with SCA from two centers in the southwestern Nigeria were investigated. Socio-demographic data, body mass index and clinical findings were documented. The urine analysis, serum bio-chemistry, hemogram and renal factors attributable to SCA were determined. Presence of albuminuria of at least 1+ or microalbuminuria in those negative with dipstick; and the estimated glomerular filtration rate (eGFR) using the Cockcroft-Gault formula categorized subjects to various stages of chronic kidney disease (CKD). Subjects with and without albuminuria were compared to determine the relative risk associated with renal disease. Four (5.6%) subjects had macro-albuminuria, while 32 (44.4%) had micro-albuminuria and 30 (41.7%) had hemoglobinuria. In the subjects with albuminuria, age, hematocrit, systolic blood pressure, serum creatinine, urea and creatinine clearance were numerically higher while the eGFR was numerically lower. There was no significant difference in the clinical parameters studied in the two groups of subjects. The diastolic blood pressure was significantly higher in the albuminuric group. Based on eGFR, 22 (30.6%) subjects had hyperfiltration (GFR > 140 mL/min/1.73 m2), of whom 36.4% had albuminuria, 18 (25.0%) had stage 1 CKD, 30 (41.7%) had stage 2 CKD and two (2.7%) subjects had stage 3 CKD with albuminuria. None had stage 4 and 5 CKD. We conclude that renal abnormalities, importantly albuminuria, is common in adult Nigerians with SCA and the pattern and incidence are similar to those reported from other parts of the world. Regular blood pressure monitoring, early diagnosis and active intervention are advocated to delay progression to end-stage kidney disease in view of poor outcomes of renal replacement therapy in SCA patients with nephropathy.