Burden and Risk Factors of Chronic Kidney Disease in Children with Sickle Cell Anaemia Aged 5 – 16 Years at the University Teaching Hospital, Lusaka - Zambia

Abstract

Background: Improved medical care has led to the improved life expectancy of sickle cell anaemia (SCA) patients hence complications associated with SCA such as chronic kidney disease (CKD) are being seen more frequently. Globally, nephropathy of varying severity occurs in 5 to 18 % of the SCA population across all age groups with a third of the adults proceeding to develop CKD while over 30 % of paediatric SCA patients have CKD in Africa. The mortality rate in SCA patients CKD is high. This study sought to determine the prevalence and risk factors of CKD in SCA, information that was not available in Zambia prior to this study. This information will guide in targeting and timing of screening for CKD in SCA in children in our population. Objectives: To determine the prevalence of haematuria, proteinuria, abnormal estimated glomerular filtration rate (eGFR), CKD, and risk factors of CKD among the steady-state SCA patients aged 5 to 16 years at the University Teaching Hospital (UTH), Lusaka. Methodology: This was a prospective cross-sectional study of 197 children aged 5 to 16 years with SCA at the UTH - Lusaka conducted from August 2014 to July 2015. Demographic and clinical data were collected using a structured questionnaire. Urine and blood samples were used to determine the urine albumin creatinine ratio (ACR) and full blood count /blood biochemistry respectively. CKD was defined and determined using the Kidney Disease Outcome Quality Initiative 2012 guidelines employing urine ACR, dipstick urinalysis and eGFR. In this study, spot urine ACR and dipstick urinalysis were done and repeated three months later if initial tests were abnormal. Data was analysed using SPSS version 21. Chi-square and t-test were used to compare proportions between groups. Relation between study variables and CKD were examined using logistic regression. Results: The mean age of the participants was 9.6 years (SD ±3.6). Male to female ratio was 1:1. The median age at diagnosis of SCA was 22 months (IQR = 44). The prevalence of haematuria, proteinuria and CKD among the study participants was 14.2%, 36% and 36 % respectively. Low haemoglobin and elevated mean corpuscular volume (MCV) were associated with CKD-AOR 0.62, 95% CI; 0.46-0.84 and 1.04, 95% CI; 1.01 – 1.08 respectively. Recurrent admissions (due to VOCs, severe anaemia and febrile illness) were also risk factors associated with CKD- AOR 0.52, 95% CI; 0.27-0.98. CKD was not associated with age at enrolment, sex, age at diagnosis of SCA, recurrent Vaso-occlusive crisis (VOCs) or abnormal liver function tests. Conclusion: The prevalence of CKD among the SCA patients at UTH- Lusaka is high (36%) with lower Haemoglobin, elevated MCV and recurrent admissions being risk factors for developing CKD. SCA patients should be screened for CKD routinely at least once a year. Interventions such as the early introduction of hydroxyurea, proactive blood transfusions and ACE inhibitors can reduce the risk of CKD and its progression to end-stage renal disease.