Renal dysfunction in patients with sickle cell anemia or sickle cell trait

Area of Science:

• Nephrology
• Hematology
• Genetics

Background:

• Sickle cell anemia (Hb SS) and sickle cell trait (Hb AS) are associated with various renal dysfunctions.
• Previous studies have not thoroughly compared the prevalence of these abnormalities between Hb SS and Hb AS patients or correlated them with disease duration.

Purpose of the Study:

• To evaluate and compare glomerular and tubular renal function in adult and pediatric patients with Hb SS and Hb AS.
• To investigate the correlation between renal abnormalities and disease duration in these patient groups.

Main Methods:

• A cross-sectional study involving 106 patients (66 with Hb SS, 40 with Hb AS) with normal glomerular filtration rate (GFR > 85 ml/min).
• Immunoenzymometric assays were used to measure tubular proteinuria, microalbuminuria, and urinary osmolality.
• Creatinine clearance and urine sediment analysis were also performed to assess renal function.

Main Results:

• Microalbuminuria was significantly higher in Hb SS patients (30%) compared to Hb AS patients (8%) (P < 0.0001).
• Microhematuria prevalence was similar in both groups (26% in Hb SS, 30% in Hb AS).
• Reduced urinary osmolality was observed in both groups, particularly in Hb SS patients over 15 years old.

Conclusions:

• Microalbuminuria is a key indicator of glomerular injury in Hb SS patients and can occur in some Hb AS individuals.
• Significant proximal tubular dysfunction is uncommon in both Hb SS and Hb AS patients with preserved GFR.
• Early renal changes in sickle cell disease include reduced urinary osmolality and increased GFR, with microhematuria also being prevalent.