Evaluation of Renal Function Biomarkers in Pre-Eclampsia: Insights from a Comparative Study in Zaria

Background: Preeclampsia is a major cause of maternal and foetal morbidity worldwide, often accompanied by renal dysfunction. Traditional markers such as serum creatinine have limited sensitivity in pregnancy. Cystatin C and uric acid have emerged as potential alternative biomarkers; however, comparative data from sub-Saharan Africa remain scarce. The study aimed to evaluate and compare the diagnostic performance of serum cystatin C, uric acid, and creatinine as renal function biomarkers in preeclamptic women in Zaria, Nigeria. Methods: A cross-sectional comparative study was conducted at Ahmadu Bello University Teaching Hospital involving 135 preeclamptic women and 135 healthy pregnant controls (>20 weeks gestation). Serum cystatin C concentrations was measured using ELISA, while uric acid and creatinine were determined using an automated chemistry analyser. Data were analysed using SPSS 25.0 and MedCalc software. Group comparisons were performed using independent t-tests or appropriate non-parametric equivalents. Pearson's correlation was used to assess inter-biomarker relationships. Receiver operating characteristic (ROC) analysis was used to evaluate diagnostic performance. Results: Mean serum cystatin C (1.49 ± 0.35 mg/L), uric acid (282.39 ± 108.92 µmol/L), and median creatinine [82.30 µmol/L (IQR: 96.0)] were significantly higher in preeclamptic women compared to controls (all p < 0.001). Cystatin C demonstrated the highest diagnostic accuracy (AUC 0.953, sensitivity 99.2%, specificity 73.0%), followed by uric acid (AUC 0.891, sensitivity 73.3%, specificity 96.3%). Creatinine showed the lowest diagnostic value (AUC 0.665). Positive correlations were observed, strongest between cystatin C and uric acid (r = 0.397, p < 0.001), suggesting shared pathophysiological pathways involving glomerular dysfunction and endothelial injury. Conclusion: Cystatin C is a highly sensitive biomarker for detecting renal dysfunction in preeclampsia, outperforming uric acid and creatinine. Uric acid's high specificity supports its adjunctive use, while creatinine remains less reliable for early detection. A multi-marker approach may enhance diagnostic accuracy and improve maternal care in resource-limited settings.