Performances of Proteinuria as Compared with Albuminuria in Screening for Microalbuminuria During Sickle Cell Anaemia

Abstract

Albuminuria is the gold standard for the screening of microalbuminuria, a biomarker of early onset of nephropathy during sickle cell anemia (SCA). Nephropathy increase morbidity and mortality of SCA in the absence of appropriate treatment. However, albuminuria is not readily available or affordable in resource-limited countries, so in 2012 Kidney Diseases Improving Global Outcomes (KDIGO) proposed using proteinuria at a threshold of 150 mg/g urine creatinine to screen for microalbuminuria in these settings. The aim of this study was therefore to assess the performance of proteinuria in screening microalbuminuria in sub-Saharan Senegalese sickle cell patients. Albuminuria in recruited SS sickle cell patients was expressed as a urine albumin-to-creatinine ratio (UACR) and proteinuria as a urine proteins-to-creatinine ratio (UPCR). The prevalence of microalbuminuria, Cohen's kappa coefficient and areas under the curve (AUC) were then determined to assess the performance of proteinuria in detecting microalbuminuria. A total of 150 patients with a median age of 20 years [minimum-maximum: 4-57] and a female proportion of 51.33% were included in the study. Microalbuminuria was present in 42.38% (n=64) of subjects according to the UPCR. The Cohen's kappa coefficient was 0.41 [IC95%: 0.27-0.56] and the AUC 0.71 [IC95%: 0.64 - 0.81] with UPCR 150mg/g. The best Cohen's kappa coefficient and AUC were observed with an UPCR threshold of 135 mg/g. Our results confirm that proteinuria is useful in screening for microalbuminuria and show that RPCU 135 mg/g would be the optimal cut-off for detecting microalbuminuria in Senegalese sickle cell anemia patients.