Sickle cell disease is typified by dramatic acute painful episodes, which consume the majority of patients’ and healthcare providers’ attention. However, the cumulative damage to vital organs that occurs in this disease is often the determinant of early death. The kidneys are a major target organ in sickle cell disease and renal failure is a highly morbid event. It is also strongly associated with early death. Glomerular hyperfiltration is often the earliest sign of renal injury. This is followed by return to apparently normal filtration rates, then successively lower rates, culminating in end-stage renal disease. Microalbuminuria follows hyperfiltration and progresses to frank proteinuria. We evaluated the prevalence of renal dysfunction in a cohort of patients with sickle cell disease managed at the University of Tennessee Cancer Institute’s adult sickle cell program. At entry into the program, patients underwent a routine battery of tests, including 24 hour urine collection for measurement of creatinine clearance and urine protein. Our findings are summarized in the table below.
By the age of 25 years, almost 80% of patients with sickle cell disease showed significant abnormality of glomerular filtration and 40% had significant proteinuria. This worsens with age. By a median of 37 years, 2 in 3 patients have developed significant proteinuria and hypofiltration has become the predominant pattern of glomerular filtration abnormality. Since renal injury is reversible in the early stages, more emphasis needs to be placed on aggressive early screening, surveillance and intervention. Intervention at the stage of hyperfiltration and microalbuminuria is easier and much more likely to be successful. Patients and their healthcare providers need to be educated on the high prevalence of renal damage. Efforts at education, screening, surveillance and, where necessary, treatment should begin well before adolescence.
