Microalbuminuria as predictor of early glomerular injury in children and adolescents with sickle cell anaemia at Muhimbili national hospital dar es salaam, Tanzania 2012

Abstract

Background: Microalbuminuria (MA) is the earliest marker of various diseases affecting the renal system. Its relevance in children and adolescents with sickle cell anaemia (SCA), who are known to be prone to renal complications, has not been fully explored in our setting. Several studies have shown microalbuminuria to be prevalent among SCA children. It is now used extensively as a sensitive test of preclinical glomerular damage. Microalbuminuria in the early stages of sickle cell nephro¬pathy is a hallmark of future deterioration of renal function. It is important to detect this early with routine surveillance. Intervention at this stage may prevent or at least delay the end stage renal disease.

Objectives: To determine the prevalence of microalbuminuria and its clinical correlates in children and adolescents with SCA attending sickle cell clinic at Muhimbili National Hospital.

Materials and Methods: This was a hospital based descriptive cross-sectional study. Children and adolescents aged 3 – 18 years attending sickle cell clinic were randomly selected. Urine sample of all eligible children and adolescent with SCA was screened for microalbuminuria by special Micral urine taste strips (Cliawaived Microlalbumin 2-1 Combo, USA),with sensitivity and specificity of 96.5% and 98.3 respectively. The resting blood pressure (BP) measurements, haemoglobin level, were obtained and clinical events associated with microalbuminuria were recorded. Data were analyzed using Statistical Package for Social Science (SPSS) version 17 statistical packages. Chi-square test was used for categorical variables, and student t test for independent sample means. Binary logistic regression was used to analyze potential effect modifiers of microalbuminuria.

Results: The study group was made up of 120 subjects aged 3 to 18 years (53% females). Microalbuminuria (MA) was found in 29/120 (24%). None of the clinical characteristics (painful crisis, blood transfusion, abnormal pressure) were significantly related with MA. Haemoglobin levels were significantly lower in subjects with MA than in those without MA (5.9±1.2 vs 7.4±1.0g/dL, respectively)p=0.001 . In multivariate logistic regression model of MA both Hb level and age remain in the final model as clinical correlates of MA. Higher Hb level showed a protective effect against MA (Odds ratio=0.55) p=0.001 while subjects with MA were more likely to have older age. (Odds ratio=1.7) p=0.001 Conclusion and Recommendations: MA is common among children and adolescents with SCA and directly related to age and inversely related to the haemoglobin levels. Urinary MA measurement is a simple and non-invasive screening biomarker which may be utilized as part of routine health care in children and adolescents with SCA. Screening for microalbuminuria seems prudent after age 6 to 7 years especially in those with severe anaemia. Longitudinal studies are essential to determine the significance of childhood microalbuminuria in the development of renal disease