Prevalence of renal failure in sickle cell disease patients attending Muhimbili national hospital in Dar es salaam, Tanzania.

Abstract

Background: Sickle-cell disease, is an inheritable hemoglobinopathy where red cells assume an abnormal, rigid, sickle shape leading to several complications, one of them, chronic renal failure. The disease is common among blacks. Renal failure in SCD patients ranges from 5 to 18 percent and contributes to 18% of the overall mortality in SCD patients. Despite its remarkable contribution in mortality, no data from Africa and especially Tanzania is available to address the extent of renal failure in SCD patients. Objective: This study aimed to determine the prevalence of renal failure and associated factors among sickle cell disease patients attending Muhimbili National Hospital in Dar es Salaam, Tanzania. Methods: A descriptive cross sectional study was done for a period of seven months, September 2010 through March 2011. During this period, patients attending the outpatient SCD clinic were enrolled and screened for features suggestive of renal failure. The data included demographic data, anthropometric measurements and clinical information. Blood for CBC, serum creatinine, urea and electrolytes was obtained, urinalysis inclusive. Renal ultrasound was performed for those with established renal failure. The end point of this study was renal failure defined by eGFR less than 60ml/min/1.73m2. The collected data was recorded cleaned, validated and finally analysed using SPSS version 15.0. Various associations between the outcome and risk factors were assessed and p-value less than 0.05 was taken as statistically significant Results: A total of 313 sickle cell disease patients were enrolled into the study. Of these 14.7% had established renal failure (i.e. with eGFR<60ml/min/1.73m2). Children under 10 years of age were predominantly affected with renal failure (P=0.01). There was no gender predilection (P=0.2).There was statistically significant association between severe anaemia and renal failure. Proteinuria and hypertension were 16.9% and 14.4% respectively however; both had no significant association with renal failure. Proteinuria was associated with advanced age. Anaemia was more severe in those with low eGFR (P 0.001). Blood urea level was significantly associated with renal failure (P<0.0001).There was established renal parenchymal disease ultrasonogarphyically in 44.4% of renal failure patients who underwent renal ultrasound. Conclusion: This study has revealed that renal failure exists in SCD patients (14.7%), as other studies have documented it to be 5 to 18 percent. The age predilection has changed from advanced age to children less than 10 years of age. Other parameters like proteinuria being common in advanced age, low incidence of hypertension (14.4%), severe anaemia in patients with renal failure, and renal parenchyma changes have remained similar. However, proteinuria and hypertension were not associated with renalfailure (P>0.5). Conclusively, early diagnosis and treatment of renal failure in sickle cell disease patients may retard progression to end stage renal disease.