Urinary Uric Acid/Creatinine Ratio as a Marker of Mortality and Unfavorable Outcome in NICU-Admitted Neonates

The Urinary Uric Acid / Cr ratio as a marker of morbidity and mortality of preterm infants: a case-control study

BACKGROUND

Perinatal asphyxia is one of the main causes of preterm infant mortality. Some studies have shown that The Urinary Uric Acid / Cr (UUA/Cr) ratio may be used as an additional marker for perinatal asphyxia.This study intend to investigate the relationship of this ratio with outcomes of preterm infants admitted to NICU.

METHODS

This case-control study was carried on 102 preterm newborn infants with gestational age of 30 weeks to 33 weeks and 6 days admitted in the neonatal intensive care unit.The case group, consisted of 51 premature neonates with a history of intubation, cardiopulmonary resuscitation, mechanical ventilation and Nasal continuous positive airway pressure (NCPAP) at birth, were compared with 51 matched neonates. The UUA/Cr ratio was measured in the first 24 h after birth. Complications during hospitalization, duration of hospitalization, and final outcome were evaluated.

RESULTS

The mean level of UUA/Cr ratio in case and control group were 5.4 ± 4.1 and 3.6 9 ± 2.9 respectively and this difference was statistically significant (p = 0.014). The UUA/Cr ratio were significantly higher in females, cesarean section delivery, Apgar score ≥ 8, neonates without any complication and neonates with less than 10 days of hospitalization. However, this ratio has no predictive value for the incidence of complications during hospitalization and long-term hospital stay for infants of the case group.

CONCLUSIONS

The Urinary Uric Acid / Cr ratio in the first 24 h after birth in preterm neonates who underwent intubation, NCPAP or cardiopulmonary resuscitation was higher than healthy neonates.

Association of Uric Acid in Serum and Urine with Arterial Stiffness: Hanzhong Adolescent Hypertension Study

Background

Hyperuricemia has long been associated with increased cardiovascular risk, and arterial stiffness is proposed as a mediator. The present study is aimed at examining the associations of uric acid (UA) in blood and urine with arterial stiffness in a Chinese cohort.

Methods

A total of 2296 participants (mean age: 43.0 years) from our previously established cohort of Hanzhong Adolescent Hypertension Study were included. The participants were classified as subjects with or without arterial stiffness, which was defined as brachial-ankle pulse wave velocity (baPWV) ≥ 1400 cm/s and/or carotid intima-media thickness (CIMT) ≥ 0.9 mm. Multivariate regression analyses were used to examine the relationship between serum and urinary UA and the risk of arterial stiffness after adjusting for age, gender, systolic blood pressure, fasting glucose, BMI, heart rate, total cholesterol, and triglycerides.

Results

baPWV was positively correlated with urinary uric acid/creatinine ratio (uUA/Cre) (β = 0.061, P < 0.001), while CIMT was correlated with uUA/Cre (β = 0.085, P < 0.001) and fractional excretion of uric acid (FEUA) (β = 0.044, P = 0.033) in all subjects. In addition, uUA/Cre was significantly associated with the risk of high baPWV [1.032 (1.019-1.045)] and arterial stiffness [1.028 (1.016-1.040)].

Conclusion

Our study showed that urinary UA excretion was significantly associated with the risk of arterial stiffness in Chinese adults. These findings suggest that UA, especially urinary UA, may be used as a simple, noninvasive marker for early detection of arterial stiffness in otherwise healthy subjects.

Association of uric acid in serum and urine with subclinical renal damage: Hanzhong Adolescent Hypertension Study

BACKGROUND AND OBJECTIVES

The aim of the study was to examine the associations of uric acid (UA) in blood and urine with subclinical renal damage (SRD) and its progression in a Chinese cohort.

METHODS

1) 2342 participants from our previously established cohort who were followed up in 2017 were included. Cross-sectional analysis was used to examine the relationships between serum and urinary UA and the risk of SRD. 2) A total of 266 participants were recruited from the same cohort in 2013, and followed up in 2017. Longitudinal analysis was used to determine the relationships of serum and urinary UA with progression of SRD, which was defined as urinary albumin-to-creatinine ratio (uACR) progression or estimated glomerular filtration rate (eGFR) decline.

RESULTS

In cross-sectional analysis, higher levels of uACR were associated with higher levels of serum uric acid (SUA) and urinary uric acid/creatinine ratio (uUA/Cre). Lower eGFR was associated with higher levels of SUA and fractional excretion of uric acid (FEUA) but lower uUA/Cre levels in all subjects. In addition, the multivariate-adjusted odds ratios for SRD compared with non-SRD were 3.574 (2.255-5.664) for uUA/Cre. Increasing uUA/Cre levels were associated with higher risk of SRD. In longitudinal analysis, 4-year changes of uUA/Cre and SUA were significantly associated with eGFR decline.

CONCLUSIONS

This study suggested that urinary UA excretion was significantly associated with the risk of SRD in Chinese adults. Furthermore, 4-year changes of serum and urinary UA were associated with SRD progression. These findings suggest that UA, especially urinary UA, may be used as a simple, noninvasive marker for early detection of decreased renal function in otherwise healthy subjects.