Neutrophil gelatinase-associated lipocalin and Fibrinogen-to-albumin ratio are indicators of nephropathy in adult steady state sickle cell disease patients: A multicenter case-control study in Ghana.

BackgroundProgressive renal failure is one of the main complications in sickle cell disease. Neutrophil Gelatinase-Associated Lipocalin (NGAL) is present in gelatinase/tertiary granules of neutrophils and it is a relatively newly recognized marker of nephropathy. Fibrinogen increases and albumin decreases in inflammatoy conditions like SCD. This study investigated the diagnostic roles of NGAL and fibrinogen-to-albumin ratio in steady state adult sickle cell disease patients. MethodsIn this study, 104 sickle cell disease participants and 51 healthy subjects were analysed. Participants information was thoroughly documented using a structured questionnaire and patient case records. To evaluate the hematobiochemical parameters, 5ml of venous blood was drawn from each participant and a clean catch of mid-stream urine was collected from each participant. Subjects with sickle cell disease were further classified as SCD nephropathy and SCD non- nephropathy subjects based on reduced estimated Glomerular Filtration Rate (eGFR) and microalbuminuria. ResultsPrevalence of nephropathy was 32.7% among adult steady state SCD patients. Significant high levels of Urine Albumin-to-Creatinine Ratio (UACR), NGAL and fibrinogen-to-albumin ratio (FAR) were seen in SCD patients with nephropathy compared to those without nephropathy (p<0.001). NGAL levels significantly increased along with increased urine albumin-to-creatinine ratio (r=0.28, p<0.005) in both SCD with nephropathy and those without nephropathy. There was a significant negative correlation between creatinine (r=-0.90, p<0.0005), urea (r=-0.50, p<0.0005) and eGFR in SCD subjects. Similarly, a significant negative relationship existed between UACR and eGFR (r=-0.34, p<0.0005). Creatinine also had a significant positive correlation with UACR (r=0.27, p<0.005 and urea (r=0.56, p<0.0005) in SCD subjects. NGAL was found to be a good predictor of nephropathy in steady state SCD patients with AUC=0.742, p<0.0001 when compared with creatinine and urea with AUC=0.618, p=0.048 and AUC=0.531, p=0.647 respectively. However, FAR could not be used as a predictive marker since it had non-significant poor performance (AUC=0.462, p=0.536). ConclusionNGAL as independent marker, is an early predictor of kidney disease as compared to urea and creatinine. Fibrinogen-to-albumin ratio can be used to track nephropathy treatment in steady state sickle cell disease patients since it is elevated in those with sickle cell nephropathy compared to healthy individuals. These two markers can be added to the available array of test in the management of nephropathy among steady SCD patients.