Glomerular filtration rate in homozygous sickle cell disease children in steady state and healthy Nigerian children: a comparative study in north-eastern Nigeria

ABSTRACT

Background: Homozygous sickle cell disease (HSCD) is the most common inherited blood disorder of public health importance worldwide, with Sub-Saharan Africa accounting for a third of the global burden. The effect of HbS on the kidneys results in sickle cell nephropathy, which contributes to increased mortality among HbSS patients beyond third decade of life. Glomerular filtration rate (GFR) is an important renal function test for evaluating progress of sickle cell nephropathy, however, this is seldom done to HbSS patients especially in the insurgency that devastated the North-eastern part of Nigeria, where displacement of people has led to increase in diarrhoeal diseases with its complications which also contributes to renal diseases, hence the need for this study. Objective: To determine the baseline glomerular filtration rate of homozygous SCD in steady state and compare same with normal controls. Methods: This is a prospective comparative study conducted at the University of Maiduguri Teaching Hospital (UMTH). The study population consisted of age and sex matched HbSS subjects in steady state and children with haemoglobin AA genotypeaged 3-14 years. The study was conducted over a period of 6 months. Anthropometry and serum creatinine of the subjects were determined and GFR calculated using Schwartz formula. Results: Two hundred and twenty children consisting 110 HbSS and 110 controls were enrolled. This consist of 106 males and 114 females with MF ratio of 0.91. Mean ages of HbSS patients and HbAA subjects were 8.2years and 7.9 years respectively. The mean GFR (SD) was 125.9 (31.9) ml/min/1.73m2 and 93.0 (16.1) ml/min/1.73m2 for the HbSS and HbAA controls, the difference between the means was significant (P<0.001). The normal GFR range for the controls was 77 to 109 ml/min/1.73m2. Sixty-seven (61%) casesand 86 (78%) controls had GFRs within normal range. There was statistically significant difference for GFRs above and below the normal range (Z-score=6.2 & -2.9, p<0.001 & p<0.004). Conclusion: About a third of HbSS children in steady state have elevated GFR, this suggests the presence of moderate renal pathology. Regular monitoring of these children will lead to improvements in management of sickle cell nephropathy and their quality of life