Random urine uric acid to creatinine and prediction of perinatal asphyxia: a meta-analysis

Objective: The purpose of the present review is to evaluate whether urine uric acid to creatinine ratio is increased in perinatal asphyxia and hypoxic-ischemic encephalopathy (HIE), as well as to assess its predictive accuracy in the disease. Methods: We used the Medline (1966-2017), Scopus (2004-2017), Clinicaltrials.gov (2008-2017), Embase (1980-2017), Cochrane Central Register of Controlled Trials CENTRAL (1999-2017), and Google Scholar (2004-2017) databases in our primary search along with the reference lists of electronically retrieved full-text papers. The hierarchical summary receiver operating characteristic (HSROC) model was used for the meta-analysis of diagnostic accuracy. Results: Fourteen studies were finally included in the present review, that investigated 1226 neonates. Urinary uric acid to creatinine ratio was significantly higher in neonates with perinatal asphyxia than in healthy controls (mean differences (MD): 1.43 95%CI [1.17, 1.69]). Specifically, the mean difference for Sarnat stage 1 was 0.70 (95%CI [0.28, 1.13]), for stage 2 1.41 (95%CI [0.99, 1.84]), and for stage 3 2.71 (95%CI [2.08, 3.35]). The estimated sensitivity for the summary point was 0.90 (95%CI (0.82-0.95)), the specificity was 0.88 (95%CI (0.73-0.95)) and the diagnostic odds ratio was calculated at 63.62 (95%CI (17.08-236.96)). Conclusions: Urinary uric acid to creatinine ratio is a rapid and an easily detected biomarker that may help physicians identify neonates at risk of developing perinatal asphyxia and HIE. However, large-scale prospective studies are still needed to determine its value in predicting mortality, as well as short- and long-term adverse neurological outcomes.