Relationship between Serum Uric Acid Concentration and Acute Kidney Injury after Coronary Artery Bypass Surgery

Uric Acid to Albumin Ratio: A Predictive Marker for Acute Kidney Injury in Isolated Tricuspid Valve Surgery

Background

The plasma uric acid/albumin ratio (UAR) has emerged as a novel inflammatory biomarker for predicting the development of acute kidney injury (AKI) following percutaneous coronary intervention. However, the potential of the UAR to serve as a predictive marker for AKI in patients undergoing isolated tricuspid valve (TV) surgery remains unknown. This study aimed to explore the association between the UAR and AKI and to assess whether the UAR can predict AKI in these patients.

Methods

We conducted a retrospective analysis of patients who underwent isolated TV surgery between January 2018 and June 2019. The patients were divided into three groups based on the tertiles of the UAR. We utilized multivariate logistic regression and restricted cubic spline analysis to examine the association between the UAR and AKI. Additionally, we used the receiver operating characteristic (ROC) curve analysis to assess the predictive accuracy of the UAR for AKI.

Results

A total of 224 patients were enrolled in this study, of whom 41 developed AKI. The incidence of AKI across the three UAR tertiles was 3.8%, 22.2%, and 29.7%, with a significant difference between the group (p < 0.001). In the multivariate analysis, UAR ≥8.5 was associated with a 7-fold increased risk of AKI (odds ratio (OR): 7.73, 95% confidence interval (CI): 1.61-37.14), while a UAR ≥10.8 was a linked to a 9-fold increased risk (OR: 9.34, 95% CI: 1.96-44.60). The restricted cubic spline model showed a linear association between the UAR and AKI development. The area under the curve (AUC) value for the UAR was 0.713 (95% CI: 0.633-0.793; p < 0.001) with a cutoff value of 8.89.

Conclusions

An increased UAR was significantly associated with a higher risk of AKI in patients undergoing isolated TV surgery; however, while the UAR could serve as a marker to predict AKI, it was not superior to uric acid alone.

The association of perioperative serum uric acid variation with in-hospital adverse outcomes in coronary artery bypass grafting patients

Background

Previous studies proposed the predictive value of baseline serum uric acid (SUA) in the prognosis of coronary artery bypass grafting (CABG) patients. The association of perioperative SUA variation with in-hospital adverse outcomes in CABG patients is unknown.

Methods

A total of 2,453 patients were included in the study and were divided into four groups (G1-G4) according to perioperative SUA variation (ΔSUA) (G1, ΔSUA ≤ -90 μmol/L; G2, -90 μmol/L < ΔSUA < 0; G3, 0 ≤ ΔSUA < 30 μmol/L; G4, 30 μmol/L ≤ ΔSUA.) The basic characteristics and incidence of adverse outcomes were compared between the groups in the overall population and the subgroups. Multivariate logistic regression was performed to explore the association between perioperative SUA increases and adverse outcomes, and receiver operating characteristic analysis was used to obtain the cutoff value of SUA increases.

Results

The patients had a mean age of 60.9 years and the majority were males (76.7%). In the group with the most significant increase in SUA (G4), incidences of in-hospital all-cause death and fatal arrhythmia were higher than in other groups in the overall population and the subgroups. Multivariate logistic regression showed that an increase in the SUA level of ≥30 µmol/L was significantly associated with in-hospital all-cause death and fatal arrhythmia, independent of the baseline SUA level and renal function. This association was significant in most subgroups for in-hospital fatal arrhythmia and in the ≥60 years, myocardial infarction, and female subgroups for in-hospital all-cause death. The cutoff values of SUA increases in the overall population were 54.5 µmol/L for in-hospital all-cause death and 42.6 µmol/L for in-hospital fatal arrhythmia.

Conclusions

The perioperative SUA increase significantly correlated with a higher incidence of in-hospital all-cause death and fatal arrhythmia in CABG patients, independent of the baseline SUA level and renal function. Perioperative SUA variation may provide complementary information in the identification of patients potentially at risk.

Prediction of Acute Kidney Injury After Coronary Artery Bypass Graft From Preoperative Serum Uric Acid

OBJECTIVE

To examine the association of an elevated level of uric acid (UA) in the bloodstream with an increased likelihood of acute kidney injury (AKI) following coronary artery bypass grafting (CABG) surgery.

DESIGN

Retrospective cohort study using a multivariate logistic regression model.

SETTING

Single institution.

PARTICIPANTS

Recipients of CABG surgery.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

A total of 761 individuals who underwent CABG were included in the study. The participants were categorized into 4 groups based on their UA level: Q1 group (UA <292.5 μmol/L), Q2 group (292.5 ≤ UA <353 μmol/L), Q3 group (353 ≤ UA < 423 μmol/L), and Q4 group (UA ≥423 μmol/L). A total of 167 patients, accounting for 21.9% of the sample, experienced postoperative AKI. The study found a significantly higher risk of AKI in the Q4 group compared to the Q1 group (40.4% v 8.9%; p < 0.001). After adjustment for confounding variables, an independent association between serum UA concentration and an elevated risk of AKI post-CABG was identified (odds ratio, 6.41; 95% confidence interval, 3.49-12.32; p < 0.001; p for trend < 0.001).

CONCLUSIONS

There is a relationship between preoperative blood UA level and the occurrence of AKI following CABG surgery.

Uric acid and acute kidney injury in high-risk patients for developing acute kidney injury undergoing cardiac surgery: A prospective multicenter study

PURPOSE

It is unclear whether preoperative serum uric acid (SUA) elevation may play a role in the development of acute kidney injury (AKI) associated with cardiac surgery (CSA-AKI). We conducted a cohort study to evaluate the influence of preoperative hyperuricemia on AKI in patients at high risk for developing SC-AKI.

DESIGN

Multicenter prospective international cohort study.

SETTING

Fourteen university hospitals in Spain and the United Kingdom.

PARTICIPANTS

We studied 261 consecutive patients at high risk of developing CSA-AKI, according to a Cleveland score ≥ 4 points, from July to December 2017.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

AKIN criteria were used for the definition of AKI. Multivariable logistic regression models and propensity score-matched pairwise analysis were used to determine the adjusted association between preoperative hyperuricemia (≥7 mg/dL) and AKI. Elevated preoperative AUS (≥7 mg/dL) was present in 190 patients (72.8%), whereas CSA-AKI occurred in 145 patients (55.5%). In multivariable logistic regression models, hyperuricemia was not associated with a significantly increased risk of AKI (adjusted Odds Ratio [OR]: 1.58; 95% confidence interval [CI]: 0.81-3; P = .17). In propensity score-matched analysis of 140 patients, the hyperuricemia group experienced similar adjusted odds of AKI (OR 1.05, 95%CI 0.93-1.19, P = .37).

CONCLUSIONS

Hyperuricemia was not associated with an increased risk of AKI in this cohort of patients undergoing cardiac surgery at high risk of developing CSA-AKI.

Off-Pump Coronary Artery Bypass Graft (OCABG) Surgery Outcome: AKI Incidence, Serum Uric Acid, and Cut-Offs of Variables

Purpose: One of the most important challenges of the medical community is to find out the success rate of coronary artery bypass surgery and control complications after surgery, including acute kidney injury (AKI). The present study was conducted with the aim of determining the predictive effect of serum uric acid (SUA) (UA) level in patients undergoing off-pump coronary artery bypass (OCABG) surgery. Methods: The present descriptive-analytical study included 144 patients who underwent OCABG and met the inclusion criteria. SUA and related indicators, duration of hospitalization and stay in ICU, AKI and in-hospital mortality, and 6-month follow-up mortality were investigated. Results: Patients were divided into high and normal groups based on SUA levels. The prevalence of postoperative AKI was 20% and was significantly associated with the preoperative UA levels (OR: 2.04; CI: 95%; 1.03-4.20). The mortality rate of patients was between 2% and 9%, which increased to 13% in patients with high SUA (p value ~0.224). The average duration of ICU and hospitalization in patients with high UA was longer than the other group (p value ~0.06 and p value ~0.002, respectively). Conclusion: SUA levels are independently associated with a higher risk of AKI and outcome complications after off-pump CABG, and confounding factors at specific cutoffs affect the odds ratio of UA for AKI occurrence.

Low preoperative serum uric acid is associated with early acute kidney injury after living donor liver transplantation

BACKGROUND

Liver transplantation is treatment option for patients with end-stage liver disease and hepatocellular carcinoma. Renal function deterioration significantly impacts the survival rates of liver recipients, and serum uric acid (SUA) is associated with both acute and chronic renal function disorders. Thus, our study aimed to assess the relationship and predictive value of preoperative SUA level and postoperative acute kidney injury (AKI) in living donor liver transplantation (LDLT).

METHODS

We conducted a prospective observational study on 87 patients undergoing LDLT. Blood samples were collected immediately before LDLT, and renal function status was followed up for 3 consecutive days postoperatively.

RESULTS

Low SUA levels (cutoff value 4.15 mg/dL) were associated with a high risk of early posttransplantation AKI. The area under the curve was 0.73 (sensitivity, 79.2%; specificity, 59.4%). Although not statistically significant, there were no deaths in the non-AKI group but two in the early AKI group secondary to liver graft dysfunction in addition to early AKI within the first month after LDLT.

CONCLUSION

AKI after liver transplantation may lead to a deterioration of patient status and increased mortality rates. We determined low preoperative SUA levels as a possible risk factor for early postoperative AKI.

Cardiac surgery-associated acute kidney injury in newborns: A meta-analysis

<b>Introduction</b>: Acute kidney injury is a common complication following pediatric heart surgery, and it has been linked to an increased risk of morbidity and fatality.<br /> <b>Methods</b>: The PubMed and Medline databases were combed for relevant research until May 2022. The terms [Cardiac surgery] AND [acute renal injury] AND [newborns OR children OR neonates] AND [randomized control studies OR randomized control trials] were used as search criteria. The studies that met the inclusion criteria were considered qualified using the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines.<br /> <b>Results</b>: A total of 2,941 newborns or children were enrolled in 14 studies, with 931 developing acute renal damage. 2,095 of the enrolled infants and children received steroid, aminophylline, dexmedetomidine, and acetaminophen therapies. In seven studies, the odds ratio for steroids was not significantly different from control. In contrast, two studies comparing aminophylline to a control group found no statistically significant change. Two studies found no significant difference in dexmedetomidine therapy compared to control. Three trials, however, found a significant difference between the acetaminophen treatment and control groups.<br /> <b>Conclusion</b>: Acetaminophen was linked to a decreased risk of postoperative acute renal injury, while steroids had no benefit and aminophylline treatment could be justified.

The Predictive Value of Hyperuricemia on Renal Outcome after Contrast-Enhanced Computerized Tomography

The aim of this study was to determine whether elevated serum level of uric acid (sUA) could predict renal outcome after contrast-enhanced computerized tomography (CCT). We used a historical cohort of 58,106 non-dialysis adult patients who received non-ionic iso-osmolar CCT from 1 June 2008 to 31 March 2015 to evaluate the association of sUA and renal outcome. The exclusion criteria were patients with pre-existing acute kidney injury (AKI), multiple exposure, non-standard volume of contrast, and missing data for analysis. A total of 1440 patients were enrolled. Post-contrast-AKI (PC-AKI), defined by the increase in serum creatinine ≥ 0.3 mg/dL within 48 h or ≥50% within seven days after CCT, occurred in 180 (12.5%) patients and the need of hemodialysis within 30 days developed in 90 (6.3%) patients, both incidences were increased in patients with higher sUA. sUA ≥ 8.0 mg/dL was associated with an increased risk of PC-AKI (odds ratio (OR) of 2.62; 95% confidence interval (CI), 1.27~5.38, p = 0.009) and the need of hemodialysis (OR, 5.40; 95% CI, 1.39~21.04, p = 0.015). Comparing with sUA < 8.0 mg/dL, patients with sUA ≥ 8.0 mg/dL had higher incidence of PC-AKI (16.7% vs. 11.1%, p = 0.012) and higher incidence of hemodialysis (12.1% vs. 4.3%, p < 0.001). We concluded that sUA ≥ 8.0 mg/dL is associated with worse renal outcome after CCT. We suggest that hyperuricemia may have potential as an independent risk factor for PC-AKI in patients receiving contrast-enhanced image study.

Uric Acid and Acute Kidney Injury in the Critically Ill

Rationale & Objective

Uric acid is excreted by the kidney and accumulates in acute kidney injury (AKI). Whether higher plasma uric acid level predisposes to AKI or its complications is not known.

Study Design

Prospective observational cohort study.

Setting & Participants

2 independent cohorts of critically ill patients: (1) 208 patients without AKI admitted to the intensive care unit (ICU) at Brigham & Women's Hospital between October 2008 and December 2016; and (2) 250 participants with AKI requiring renal replacement therapy (RRT) who had not yet initiated RRT enrolled in the Acute Renal Failure Trial Network (ATN) Study.

Exposure

Plasma uric acid level upon ICU admission and before RRT initiation in the ICU and ATN Study cohorts, respectively.

Outcomes

Incident AKI and 60-day mortality in the ICU and ATN Study cohorts, respectively.

Analytical Approach

Logistic regression models were used to test the association of plasma uric acid level with incident AKI and 60-day mortality.

Results

In the ICU cohort, median plasma uric acid level was 4.7 (interquartile range [IQR], 3.6-6.4) mg/dL, and 40 patients (19.2%) developed AKI. Higher plasma uric acid levels associated with incident AKI, but this association was confounded by serum creatinine level and was not significant after multivariable adjustment (adjusted OR per doubling of uric acid, 1.50; 95% CI, 0.80-2.81). In the ATN Study cohort, median plasma uric acid level was 11.1 (IQR, 8.6-14.2) mg/dL, and 125 participants (50.0%) died within 60 days. There was no statistically significant association between plasma uric acid levels and 60-day mortality in either unadjusted models or after multivariable adjustment for demographic, severity-of-illness, and kidney-specific covariates (adjusted OR per doubling of uric acid, 1.15; 95% CI, 0.71-1.86).

Limitations

Heterogeneity of ICU patients.

Conclusions

Plasma uric acid levels upon ICU admission or before RRT initiation are not independently associated with adverse clinical outcomes in critically ill patients.

Risk Factor Analysis for AKI Including Laboratory Indicators: a Nationwide Multicenter Study of Hospitalized Patients

BACKGROUND/AIMS

Risk factor studies for acute kidney injury (AKI) in China are lacking, especially those regarding non-traditional risk factors, such as laboratory indicators.

METHODS

All adult patients admitted to 38 tertiary and 22 secondary hospitals in China in any one month between July and December 2014 were surveyed. AKI patients were screened according to the Kidney Disease: Improving Global Outcomes' definition of AKI. Logistic regression was used to analyze the risk factors for AKI, and Cox regression was used to analyze the risk of in-hospital mortality for AKI patients; additionally, a propensity score analysis was used to reconfirm the risk factors among laboratory indicators for mortality.

RESULTS

The morbidity of AKI was 0.97%. Independent risk factors for AKI were advancing age, male gender, hypertension, and chronic kidney disease. All-cause mortality was 16.5%. The predictors of mortality in AKI patients were advancing age, tumor, higher uric acid level and increases in Acute Physiologic Assessment and Chronic Health Evaluation II and Sequential Organ Failure Assessment scores. The hazard ratio (HR) for mortality with uric acid levels > 9.1 mg/dl compared with ≤ 5.2 mg/dl was 1.78 (95% CI: 1.23 to 2.58) for the AKI patients as a group, and was 1.73 (95% CI: 1.24 to 2.42) for a propensity score-matched set.

CONCLUSION

In addition to traditional risk factors, uric acid level is an independent predictor of all-cause mortality after AKI.

Uric acid in the pathogenesis of metabolic, renal, and cardiovascular diseases: A review

The association between uric acid (UA) on one side and systemic hypertension (Htn), dyslipidemia, glucose intolerance, overweight, fatty liver, renal disease and cardiovascular disease (CVD) on the other side is well recognized. However, the causal relationship between UA and these different clinical problems is still debatable. The recent years have witnessed hundreds of experimental and clinical trials that favored the opinion that UA is a probable player in the pathogenesis of these disease entities. These studies disclosed the strong association between hyperuricemia and metabolic syndrome (MS), obesity, Htn, type 2 diabetes mellitus (DM), non-alcoholic fatty liver disease, hypertriglyceridemia, acute kidney injury, chronic kidney disease (CKD), coronary heart disease (CHD), heart failure and increased mortality among cardiac and CKD patients. The association between UA and nephrolithiasis or preeclampsia is a non-debatable association. Recent experimental trials have disclosed different changes in enzyme activities induced by UA. Nitric oxide (NO) synthase, adenosine monophosphate kinase (AMPK), adenosine monophosphate dehydrogenase (AMPD), and nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase are affected by UA. These changes in enzymatic activities can lead to the observed biochemical and pathological changes associated with UA. The recent experimental, clinical, interventional, and epidemiologic trials favor the concept of a causative role of UA in the pathogenesis of MS, renal, and CVDs.

[Relationship between hyperuricemia and adverse events in patients aged 40 years or older receiving rheumatic aortic valve replacement]

OBJECTIVE

To explore the prognostic value of hyperuricemia for adverse events in patients >40 years old receiving valve replacement surgery for rheumatic aortic valve disease.

METHDS

Consecutive middle-aged and elderly patients receiving aortic valve replacement surgery for rheumatic aortic valve disease between March, 2009 and July, 2013 were recruited in this study. The patients were divided into hyperuricemic group and normouricemic group based on their serum levels of uric acid, and the clinical data and adverse events within 1 year after the surgery were compared between the 2 groups.

RESULTS

A total of 632 consecutive patients were recruited, including 381 patients with hyperuricemia and 251 with normouricemia. The in-hospital mortality rate was significantly higher in hyperuricemic group than in normouricemic group (7.6% vs 2.0%, P=0.002). Serum uric acid levels were negatively correlated with eGFR (r=-0.421, P<0.001) and positively correlated with C-reactive protein level (r=0.093, P=0.025). Multivariate analysis showed that hyperuricemia was independently associated with the in-hospital mortality (OR=3.07, 95%CI: 1.13-8.37, P=0.028) and mortality at 1 year after the surgery (HR=3.14, 95%CI: 1.30-7.62, P=0.011) after adjusting for potential risk factors including age, NYHA III-IV and postoperative acute kidney injury (AKI). Kaplan-Meier analysis showed that the cumulative rate of 1-year mortality after surgery was significantly higher in patients with hyperuricemia (Log-rank=11.73, P=0.001).

CONCLUSION

Hyperuricemia is a predictor of in-hospital and one-year mortality in middle-aged and elderly patients following aortic valve replacement surgery for rheumatic aortic valve disease.

[Relationship between hyperuricemia and adverse events in patients aged 40 years or older receiving rheumatic aortic valve replacement]

OBJECTIVE

To explore the prognostic value of hyperuricemia for adverse events in patients >40 years old receiving valve replacement surgery for rheumatic aortic valve disease.

METHDS

Consecutive middle-aged and elderly patients receiving aortic valve replacement surgery for rheumatic aortic valve disease between March, 2009 and July, 2013 were recruited in this study. The patients were divided into hyperuricemic group and normouricemic group based on their serum levels of uric acid, and the clinical data and adverse events within 1 year after the surgery were compared between the 2 groups.

RESULTS

A total of 632 consecutive patients were recruited, including 381 patients with hyperuricemia and 251 with normouricemia. The in-hospital mortality rate was significantly higher in hyperuricemic group than in normouricemic group (7.6% vs 2.0%, P=0.002). Serum uric acid levels were negatively correlated with eGFR (r=-0.421, P<0.001) and positively correlated with C-reactive protein level (r=0.093, P=0.025). Multivariate analysis showed that hyperuricemia was independently associated with the in-hospital mortality (OR=3.07, 95%CI: 1.13-8.37, P=0.028) and mortality at 1 year after the surgery (HR=3.14, 95%CI: 1.30-7.62, P=0.011) after adjusting for potential risk factors including age, NYHA III-IV and postoperative acute kidney injury (AKI). Kaplan-Meier analysis showed that the cumulative rate of 1-year mortality after surgery was significantly higher in patients with hyperuricemia (Log-rank=11.73, P=0.001).

CONCLUSION

Hyperuricemia is a predictor of in-hospital and one-year mortality in middle-aged and elderly patients following aortic valve replacement surgery for rheumatic aortic valve disease.

Are There Modifiable Risk Factors to Improve AKI?

Acute kidney injury (AKI) is a common critical syndrome, with high morbidity and mortality. Patients with AKI typically have an adverse prognosis, from incident chronic kidney disease (CKD), progression to end-stage renal disease (ESRD), subsequent cardiovascular disease, and ultimately death. However, there is currently no effective therapy for AKI. Early detection of risk factors for AKI may offer a good approach to prevention or early intervention. Traditional risk factors include extreme age, many common comorbid diseases, such as preexisting CKD, some specific exposures, such as sepsis, and exposure to some nephrotoxic agents. Recently, several novel risk factors for AKI, such as hyperuricemia, hypoalbuminemia, obesity, anemia, and hyperglycemia, have been identified. The underlying mechanisms between these nontraditional risk factors and AKI and whether their correction can reduce AKI occurrence remain to be clarified. This review describes the current epidemiology of AKI, summarizes its outcome, outlines the traditional risk profile, and finally highlights some recently identified novel risk factors.

Hyperuricemia increases the risk of acute kidney injury: a systematic review and meta-analysis

Background

Mounting evidence indicated that the elevated serum uric acid level was associated with an increased risk of acute kidney injury (AKI). Our goal was to systematically evaluate the correlation of serum uric acid (SUA) level and incidence of AKI by longitudinal cohort studies.

Methods

We searched electronic databases and the reference lists of relevant articles. 18 cohort studies with 75,200 patients were analyzed in this random-effect meta-analysis. Hyperuricemia was defined as SUA levels greater than 360-420 μmol/L (6–7 mg/dl), which was various according to different studies. Data including serum uric acid, serum creatinine, and incidence of AKI and hospital mortality were summarized using random-effects meta-analysis.

Results

The hyperuricemia group significantly exerted a higher risk of AKI compared to the controls (odds ratio OR 2.24, 95% CI 1.76-2.86, p < 0.01). Furthermore, there is less difference of the pooled rate of AKI after cardiac surgery between hyperuricemia and control group (34.3% vs 29.7%, OR 1.24, 95% CI 0.96-1.60, p = 0.10), while the rates after PCI were much higher in hyperuricemia group than that in control group (16.0% vs 5.3%, OR 3.24, 95% CI 1.93-5.45, p < 0.01). In addition, there were significant differences in baseline renal function at admission between hyperuricemia and control groups in most of the included studies. The relationship between hyperuricemia and hospital mortality was not significant. The pooled pre-operative SUA levels were higher in AKI group than that in the non-AKI group.

Conclusions

Elevated SUA level showed an increased risk for AKI in patients and measurements of SUA may help identify risks for AKI in these patients.