Urinary Uric Acid and Creatinine Ratio as a Marker of Perinatal Asphyxia

Background: Prediction of the outcome of perinatal asphyxia (PA) is important but formidable. Apgar score has a limited role in predicting the outcome. Urinary uric acid and creatinine ratio (UA/Cr) is an early, noninvasive, and cheap biomarker of PA which may predict its morbidity. This study aimed to determine the urinary UA/Cr in neonates with PA, compare it with UA/Cr in non-asphyxiated neonates, and derive the optimum cut-off value of this ratio to label PA. Methods: This observational cross-sectional study was carried out on ۱۰۰ term neonates appropriate for gestational age (AGA) with PA (cases) and ۱۰۰ non-asphyxiated term AGA babies (controls). Urine samples were collected within ۲۴ h of life; moreover, uric acid and creatinine levels were determined by an auto-analyzer. Results: The mean urinary UA/Cr ratio was significantly higher in the cases, compared to the controls (۳.۴۱±۰.۶۸ vs. ۱.۹۹±۰.۲۳) (P<۰.۰۰۰۱). The cut-off value of this ratio to label PA was>۲.۵ with sensitivity, specificity, positive predictive value, and negative predictive value of ۹۸%. Urinary UA/Cr ratio and cord blood pH were significantly correlated with each other (correlation coefficient r=-۰.۸۹۵۱, P<۰.۰۰۱). Moreover, the urinary UA/Cr ratio and ۵-min Apgar score were also significantly correlated with each other (r=-۰.۸۸۰۶, P<۰.۰۰۱). Conclusion: Urinary UA/Cr ratio is a non-invasive, cheap, and reliable marker for PA with good predictive value in this study.    

Keywords:

cord blood pH , Perinatal asphyxia , Urinary UA/Cr ratio