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

Abstract

Introduction: Perinatal asphyxia is a very common problem which significantly contributes to neonatal morbidity and mortality, contributing to almost 20% of neonatal deaths in India. It is an important cause of static developmental and neurological morbidity. Early identification of asphyxiated babies to take timely appropriate measures is our priority. Several measures like foetal heart monitoring, Appearance, Pulse, Grimace, Activity, Respiration score (APGAR), Cord blood pH, Computerised Tomography (CT), Magnetic Resonance Imaging (MRI), Doppler studies etc., are already in use for early identification of asphyxia; but they are costly and have several other limitations. Urinary Uric Acid and Creatinine Ratio (UA/Cr) is a non-invasive test, easy to conduct in resource poor setup and an early marker of asphyxia, which prompted the authors to conduct the present study. Aim: To assess the correlation of urinary uric acid and creatinine ratio with perinatal asphyxia and observe any correlation between this ratio with the severity of Hypoxic Ischaemic Encephalopathy (HIE). Materials and Methods: This was a prospective case control study conducted in Patna Medical College and Hospital, Patna, Bihar, India, between January 2019 to March 2020. A total of 100 asphyxiated term neonates as cases and 100 non-asphyxiated term neonates as controls were included in the study. Spot urine samples were collected and urinary uric acid and creatinine were estimated. Statistical analysis was carried out using Statistical Package for the Social Sciences (SPSS version. 16.0) software and p-value <0.05 was considered as statistically significant. Results: A higher urinary UA/Cr ratio of 2.99±0.14 was seen in case group compared to control group (0.77±0.03) and the higher ratio was also associated with significant neurological abnormalities. A highly significant difference was noted between case and control i.e., p<0.001 with 95% CI of 1.95-2.49. Conclusion: Urinary uric acid and creatinine ratio enables early recognition of asphyxial injury and also is a good indicator for subsequent morbidity and mortality. These measurements require simple instruments with low cost involvement. The correlation between the urinary UA/Cr ratio and the severity of HIE provides an indication for the degree of injury at an early stage when other quantitative methods cannot be carried out frequently. Therefore, this ratio can be used as an early marker of asphyxial injury and can predict neurological deficit.