Urinary neutrophil gelatinase associated lipocalin (NGAL), a marker of tubular damage, is increased in patients with chronic heart failure

Biomarkers of renal injury and function: diagnostic, prognostic and therapeutic implications in heart failure

Heart failure guidelines suggest evaluating renal function as a routine work-up in every patient with heart failure. Specifically, it is advised to calculate glomerular filtration rate and determine blood urea nitrogen. The reason for this is that renal impairment and worsening renal function (WRF) are common in heart failure, and strongly associate with poor outcome. Renal function, however, consists of more than glomerular filtration alone, and includes tubulointerstitial damage and albuminuria. For each of these renal entities, different biomarkers exist that have been investigated in heart failure. Hypothetically, and in parallel to data in nephrology, these markers may aid in the diagnosis of renal dysfunction, or for risk stratification, or could help in therapeutic decision-making. However, as reviewed in the present manuscript, while these markers may carry prognostic information (although not always additive to established markers of renal function), their role in predicting WRF is limited at best. More importantly, none of these markers have been evaluated as a therapeutic target nor have their serial values been used to guide therapy. The evidence is most compelling for the oldest-serum creatinine (in combination with glomerular filtration rate)-but even for this biomarker, evidence to guide therapy to improve outcome is circumstantial at best. Although many new renal biomarkers have emerged at the horizon, they have only limited usefulness in clinical practice until thoroughly and prospectively studied. For now, routine measurement of (novel) renal biomarkers can help to determine cardiovascular risk, but there is no role for these biomarkers to change therapy to improve clinical outcome in heart failure.

Plasma kidney injury molecule-1 in heart failure: renal mechanisms and clinical outcome

AIMS

Urinary kidney injury molecule-1 (KIM-1) is a marker of tubular damage and associated with worse outcome in heart failure (HF). Plasma KIM-1 has not been described in HF.

METHODS AND RESULTS

In a renal mechanistic cohort of 120 chronic HF patients, we established the association between plasma KIM-1, renal invasive haemodynamic parameters {renal blood flow ([(131) I]hippuran clearance) and measured glomerular filtration rate (GFR; [(125) I]iothalamate)} and urinary tubular damage markers. The association between plasma KIM-1, plasma creatinine, and clinical outcome was further explored in a cohort of 2033 acute HF patients. Median plasma KIM-1 was 171.5 pg/mL (122.8-325.7) in chronic (n = 99) and 295.1 pg/mL (182.2-484.2) in acute HF (n = 1588). In chronic HF, plasma KIM-1 was associated with GFR (P < 0.001), creatinine, and cystatin C. Plasma KIM-1 was associated with urinary N-acetyl-β-d-glucosaminidase (NAG), but not with other urinary tubular damage markers. Log plasma KIM-1 predicted adverse clinical outcome after adjustment for age, gender, and GFR [hazard ratio (HR) 1.94, 95% confidence interval (CI) 1.07-3.53, P = 0.030]. Statistical significance was lost after correction for NT-proBNP (HR 1.61, 95% CI 0.81-3.20, P = 0.175). In acute HF, higher plasma KIM-1 levels were associated with higher creatinine, lower albumin, and presence of diabetes. Log plasma KIM-1 predicted 60-day HF rehospitalization (HR 1.27, 95% CI 1.03-1.55, P = 0.024), but not 180-day mortality or 60-day death or renal or cardiovascular rehospitalization.

CONCLUSIONS

Plasma KIM-1 is associated with glomerular filtration and urinary NAG, but not with other urinary tubular damage markers. Plasma KIM-1 does not predict outcome in chronic HF after correction for NT-proBNP. In acute HF, plasma KIM-1 predicts HF rehospitalization in multivariable analysis.

Serum neutrophil gelatinase-associated lipocalin is associated with cardiovascular events in patients with chronic kidney disease

BACKGROUND

Neutrophil gelatinase-associated lipocalin (NGAL) is a member of the lipocalin family best known as a novel and early marker of acute kidney injury (AKI). Recent data suggest that NGQueryAL is not only a marker of AKI, but also an important player in the vascular remodeling, atherosclerotic plaque stability and thrombus formation. We conducted this study to investigate the association of serum NGAL levels with fatal and composite (fatal and non-fatal) cardiovascular events (CVE) in a cohort of patients with stage 1-5 CKD.

METHODS

This was an observational cohort study in which serum NGAL was obtained from 298 CKD (stages 1-5) patients. Fatal and composite CVE were recorded for a median 41 months. We examined alteration of serum NGAL through CKD groups as well as association with inflammatory markers. We also performed a Cox regression analysis to determine the association of NGAL with predefined clinical outcomes.

RESULTS

The median value of NGAL was 50.5 ng/mL (IR 47.6-54.9 ng/mL), and higher NGAL values were recorded in diabetic patients. In a multiple linear regression model, including all univariate associates of NGAL, only log eGFR, log hs-CRP and log HDL cholesterol maintained an independent association with log NGAL. During the observational period, 30 patients died due to cardiovascular causes and 69 non-fatal CVE were registered. In the fully adjusted model, we observed a 2.08-fold increase in the risk of fatal CVE and a 1.50-fold increase in the risk of fatal and non-fatal CVE for each increment of 1 SD in log NGAL values.

CONCLUSIONS

This is the first study that shows that serum NGAL is associated with cardiovascular events (fatal and non-fatal) in patients with CKD, independently of traditional risk factors, renal function and inflammation.

Prevalence of Albuminuria in a General Population Cohort of Patients With Established Chronic Heart Failure

BACKGROUND

Numerous studies have reported an association between albuminuria and adverse outcomes in adults with chronic heart failure (CHF). However, the prevalence of albuminuria in adults with established CHF remains unclear.

METHODS AND RESULTS

This study was a cross-sectional analysis of the National Health and Nutrition Examination Survey (NHANES) 1999-2012. Adults aged ≥18 years were included, and diagnosis of CHF was based on participant self-report. The primary outcome was the prevalence of microalbuminuria (albumin-to-creatinine ratio 30-300 mg/g) and macroalbuminuria (albumin-to-creatinine ratio >300 mg/g) in adults with CHF. The secondary outcome was the adjusted odds ratio of any albuminuria in adults with and without CHF. During the study period, 37,961 adults did not have CHF and 1,214 adults had CHF. In adults with CHF, 22.1% (95% confidence interval [CI] 19.6%-24.7%) had microalbuminuria and 10.4% (95% CI 8.1%-12.7%) macroalbuminuria. In adjusted analyses, the odds of albuminuria in adults with CHF was 1.89-fold higher (95% CI 1.59-2.26; P < .001) than in adults without CHF.

CONCLUSIONS

Taken together, albuminuria is more common in adults with CHF than in those without CHF, even after adjustment for important demographic and clinical confounders.

Long-term changes in renal function and perfusion in heart failure patients with reduced ejection fraction

INTRODUCTION

Little is known about the natural course of renal function and renal hemodynamics in heart failure patients with reduced ejection fraction (HFREF).

METHODS AND RESULTS

We prospectively studied effective renal plasma flow (ERPF) and glomerular filtration rate (GFR) in 73 HFREF patients with (125)I-iothalamate/(131)I-hippuran clearances with a mean follow-up of 34.6 ± 4.4 months. Fifteen percent were female, with age 58 ± 12 years and left ventricular ejection fraction (LVEF) 29 ± 10%. Baseline GFR was 81 ± 23 mL/min/1.73 m(2) and declined 0.6 ± 4.7 mL/min/1.73 m(2) per year. Baseline ERPF was 292 ± 83 mL/min/1.73 m(2) and declined 4.3 ± 19 mL/min/1.73 m(2) per year. Of the baseline variables, older age and high urinary kidney injury molecule-1 were the only variables associated with GFR decline (p < 0.05). Following stepwise backward analysis, only age (p < 0.001) remained significant. In addition, we found an association between change in GFR and changes in ERPF, N-terminal pro-brain natriuretic peptide and renovascular resistance. In the multivariable analysis, only the change in ERPF remained significantly associated with a change in GFR (p < 0.001).

CONCLUSION

In this cohort of stable chronic HFREF patients, the average decline in GFR over time was small. The decline of GFR was associated with a higher age and a lower baseline GFR, and was strongly related to changes in renal perfusion.

The role of urine neutrophil gelatinase--associated lipocalin (NGAL) in acute heart failure in patients with ST--elevation myocardial infarction

BACKGROUND

Neutrophil gelatinase-associated lipocalin (NGAL) is a novel early marker of acute kidney injury for which has been shown that it can also be released from the injured myocardium. Our aim was to correlate urine NGAL with markers of in-hospital heart failure in patients with acute ST-elevation myocardial infarction (STEMI).

METHODS

We prospectively included 61 consecutive STEMI patients after primary percutaneous coronary intervention and estimated admission and in-hospital urine NGAL, serum creatinine, troponin I, leucocytes, CRP, N-terminal pro brain natriuretic peptide (NT-proBNP) levels and ejection fraction by echocardiography. Urine NGAL levels were compared between patients with and without HF defined as serum NT-proBNP > 400 pmol/l and were correlated to markers of heart failure, inflammations and of kidney function.

RESULTS

Urine NGAL levels and CRP was significantly higher in participants with heart failure compared to those with NT-proBNP below 400 pmol/l. Urine NGAL level of 50 ng/ml had 90 % specificity for HF, the sensitivity was low at 25 %. Comparison of participants with NGAL levels < 50 ng/ml and ≥ 50 ng/ml at admission and after 12 h revealed a significant difference in NT-proBNP levels, left ventricle ejection fraction, markers of inflammation and of kidney function. Urine NGAL level was independently associated with NT-proBNP level.

CONCLUSIONS

The level of urine NGAL early after myocardial infarction is associated with NT-proBNP concentration and even NGAL levels below 137 ng/ml, the usually reported normal cut-off value, had high specificity for HF in our sample.

The role of neutrophil gelatinase associated lipocalin (NGAL) as biological constituent linking depression and cardiovascular disease

Depression is more common in patients with cardiovascular disease than in the general population. Conversely, depression is a risk factor for developing cardiovascular disease. Comorbidity of these two pathologies worsens prognosis. Several mechanisms have been indicated in the link between cardiovascular disease and depression, including inflammation. Systemic inflammation can have long-lasting effects on the central nervous system, which could be associated with depression. NGAL is an inflammatory marker and elevated plasma levels are associated with both cardiovascular disease and depression. While patients with depression show elevated NGAL levels, in patients with comorbid heart failure, NGAL levels are significantly higher and associated with depression scores. Systemic inflammation evokes NGAL expression in the brain. This is considered a proinflammatory effect as it is involved in microglia activation and reactive astrocytosis. Animal studies support a direct link between NGAL and depression/anxiety associated behavior. In this review we focus on the role of NGAL in linking depression and cardiovascular disease.

Evaluation of chronic kidney disease in chronic heart failure: From biomarkers to arterial renal resistances

Chronic kidney disease and its worsening are recurring conditions in chronic heart failure (CHF) which are independently associated with poor patient outcome. The heart and kidney share many pathophysiological mechanisms which can determine dysfunction in each organ. Cardiorenal syndrome is the condition in which these two organs negatively affect each other, therefore an accurate evaluation of renal function in the clinical setting of CHF is essential. This review aims to revise the parameters currently used to evaluate renal dysfunction in CHF with particular reference to the usefulness and the limitations of biomarkers in evaluating glomerular dysfunction and tubular damage. Moreover, it is reported the possible utility of renal arterial resistance index (a parameter associated with abnormalities in renal vascular bed) for a better assesment of kidney disfunction.

Neutrophil gelatinase-associated lipocalin (NGAL) in heart transplant recipients after conversion to everolimus therapy

BACKGROUND

Due to the lack of nephrotoxic activity, proliferation signal inhibitors (PSI) such as everolimus are recommended for immunosuppression after heart transplantation, but the assessment of renal function in patients receiving PSI has led to conflicting results. We examined renal integrity and function using neutrophil gelatinase-associated lipocalin (NGAL) and conventional markers [plasma creatinine, cystatin C, urine albumin, α1-microglobulin (α1M)] in heart transplant patients, who underwent conversion to everolimus due to allograft vasculopathy, graft rejection episodes, or renal function deterioration, and in patients maintained on calcineurin inhibitors (CNI).

METHODS

This cross-sectional study included 121 consecutive heart transplant recipients: 44 patients received CNI-free immunosuppressive therapy with everolimus and 77 patients received CNI. Renal parameters were determined in plasma and urine samples using standard enzymatic or immunochemical methods.

RESULTS

Heart transplant recipients receiving everolimus therapy had significantly lower NGAL concentrations in plasma [median (95% CI): 128 (97-176)ng/mL vs. 252 (224-283)ng/mL, p<0.001] and urine [median (95% CI): 6.4 (4.5-7.6)ng/g vs. 15.7 (10.2-25.9)ng/g creatinine, p<0.001]. In contrast, no significant differences were observed between everolimus- and CNI-treated groups with regard to creatinine and cystatin C, as well as urine albumin and α1M levels. Significant correlations were noted between plasma NGAL and creatinine (r=0.42, p<0.001), cystatin C (r=0.44, p<0.001), N-terminal brain natriuretic propeptide (r=0.31, p<0.01) and indicators of chronic inflammation [lipoprotein-associated phospholipase A2 (Lp-PLA2), r=0.31, p<0.01] and soluble CD40 ligand (sCD40L, r=0.22, p<0.05), and between urinary NGAL and α1M (r=0.21, p<0.05). Multiple regression analysis indicated that cystatin C and Lp-PLA2 were the best predictors of plasma NGAL.

CONCLUSION

The present study documents reduced plasma and urinary NGAL levels in the absence of differences in conventional renal parameters in patients on CNI-free immunosuppressive therapy with everolimus. These results support favorable effects of everolimus on renal integrity in heart transplant recipients.

Emerging biomarkers in heart failure and cardiac cachexia

Biomarkers are objective tools with an important role for diagnosis, prognosis and therapy optimization in patients with heart failure (HF). To date, natriuretic peptides are closest to optimal biomarker standards for clinical implications in HF. Therefore, the efforts to identify and test new biomarkers in HF are reasonable and justified. Along the natural history of HF, cardiac cachexia may develop, and once at this stage, patient performance and prognosis is particularly poor. For these reasons, numerous biomarkers reflecting hormonal, inflammatory and oxidative stress pathways have been investigated, but only a few convey relevant information. The complex pathophysiology of HF appears far too complex to be embraced by a single biomarker; thus, a combined approach appears reasonable. With these considerations, we have reviewed the recent developments in the field to highlight key candidates with diagnostic, prognostic and therapy optimization properties, either alone or in combination.

Novel renal biomarkers to assess cardiorenal syndrome

Renal dysfunction (RD) in heart failure portends adverse outcomes and often limits aggressive medical and decongestive therapies. Despite the high prevalence in this population, not all forms of RD are prognostically or mechanistically equivalent: RD can result from irreversible nephron loss secondary to diabetic or hypertensive kidney disease or it can develop secondary to heart failure (HF) itself, i.e., the cardiorenal syndrome. Furthermore, filtration is only one aspect of renal performance such that significant renal impairment secondary to cardiorenal syndrome can exist despite a normal glomerular filtration rate. Renal biomarkers have the potential to inform some of the intricacies involved in accurately assessing cardiorenal interactions. This article discusses novel biomarkers for cardiorenal syndrome and their utility in the prognosis, diagnosis, and targeted treatment of heart failure-induced RD.

When cardiac failure, kidney dysfunction, and kidney injury intersect in acute conditions: the case of cardiorenal syndrome

OBJECTIVE

To review and describe diagnostic and prognostic value of biomarkers of renal function and renal injury in the cardiorenal syndrome complicating acutely decompensated heart failure.

DATA SOURCES

PubMed search and review of relevant medical literature.

STUDY SELECTION

Two reviewers screened and selected studies in English with diagnostic or prognostic assessment of biomarkers of renal injury.

DATA EXTRACTION

Narrative review of the medical literature.

DATA SYNTHESIS

Cardiorenal syndrome has a complex pathophysiology and has a generally poor prognosis in patients with acutely decompensated heart failure. Among the methods to recognize risk for cardiorenal syndrome may be the use of circulating or urinary biomarkers, which may allow for more accurate early diagnosis and risk stratification; use of biomarkers may provide important pathophysiologic understanding beyond risk prediction. However, different phenotypes of patients with acute renal dysfunction may be present, which has ramifications with respect to response to treatment strategies. Addition of biomarkers of renal injury may provide additional prognostic value to biomarkers of renal or cardiac function, but more data are needed.

CONCLUSIONS

Biomarkers reflecting renal function and injury are likely to better phenotype subgroups of patients with cardiorenal syndrome and to provide unique prognostic information. Future studies are needed relative to strategies using such biomarkers to guide care of affected patients.

Biomarkers in cardiorenal syndrome

Cardiac and renal diseases often coexist. Treatment may prove difficult as early diagnosis and effective therapy may be hindered by a lack of robust markers of disease activity. However, several candidate molecules are now available which may help elucidate the complexities of organ cross-talk, enabling effective therapies. We discuss the available data on the commonly studied biomarkers of acute kidney injury with reference to the cardiorenal syndrome. Furthermore, we propose how the use of biomarkers as a panel may provide information which can guide therapy. Although this is a relatively new field, advances are rapid, and such options may well be available to the clinician soon.

Neutrophil gelatinase-associated lipocalin: ready for routine clinical use? An international perspective

Acute kidney injury (AKI) remains a challenge in terms of diagnosis and classification, its morbidity and mortality remaining high in the face of improving clinical protocols. Current clinical criteria use serum creatinine (sCr) and urine output to classify patients. Ongoing research has identified novel biomarkers that may improve the speed and accuracy of patient evaluation and prognostication, yet the route from basic science to clinical practice remains poorly paved. International evidence supporting the use of plasma neutrophil gelatinase-associated lipocalin (NGAL) as a valuable biomarker of AKI and chronic kidney disease (CKD) for a number of clinical scenarios was presented at the 31st International Vicenza Course on Critical Care Nephrology, and these data are detailed in this review. NGAL was shown to be highly useful alongside sCr, urinary output, and other biomarkers in assessing kidney injury; in patient stratification and continuous renal replacement therapy (CRRT) selection in paediatric AKI; in assessing kidney injury in conjunction with sCr in sepsis; in guiding resuscitation protocols in conjunction with brain natriuretic peptide in burn patients; as an early biomarker of delayed graft function and calcineurin inhibitor nephrotoxicity in kidney transplantation from extended criteria donors; as a biomarker of cardiovascular disease and heart failure, and in guiding CRRT selection in the intensive care unit and emergency department. While some applications require further clarification by way of larger randomised controlled trials, NGAL nevertheless demonstrates promise as an independent biological marker with the potential to improve earlier diagnosis and better assessment of risk groups in AKI and CKD. This is a critical element in formulating quick and accurate decisions for individual patients, both in acute scenarios and in long-term care, in order to improve patient prognostics and outcomes.

Novel urinary biomarkers in detecting acute kidney injury, persistent renal impairment, and all-cause mortality following decongestive therapy in acute decompensated heart failure

BACKGROUND

New urinary biomarkers, such as neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), and interleukin-18 (IL-18), are proposed to allow a more reliable early diagnosis and prognosis of acute kidney injury (AKI) in acute decompensated heart failure (ADHF). Our aim was to compare the predictive value of urinary NGAL, KIM-1, and IL-18 for the occurrence of AKI, persistent renal impairment, and mortality in ADHF.

METHODS AND RESULTS

Eighty-three patients admitted for ADHF were analyzed. Urinary creatinine (Cr), NGAL, KIM-1, and IL-18 were measured at baseline. Serum Cr was measured daily during the next 4 days and again at outpatient follow-up after 6 months. Mortality data were prospectively collected. Urinary NGAL, KIM-1, and IL-18 were modestly correlated with each other (Spearman ρ ≤0.61) and poorly correlated with estimated glomerular filtration rate (eGFR; Spearman ρ ≤0.28). None predicted AKI, defined as a 25% decrease in eGFR, during the index hospitalization, but urinary IL-18/Cr was the strongest predictor of persistently elevated serum Cr ≥0.3 mg/dL after 6 months compared with baseline (area under the receiver operating characteristic curve 0.674; P = .013). Urinary IL-18 was also significantly associated with all-cause mortality (hazard ratio 1.48, 95% confidence interval 1.16-1.87; P = .001).

CONCLUSIONS

Like urinary NGAL, urinary KIM-1 and IL-18 are relatively modest predictors of AKI in ADHF. Among these novel renal biomarkers examined, further investigations regarding the prognostic value of urinary IL-18 are warranted.

Neutrophil Gelatinase-Associated Lipocalin and depression in patients with chronic heart failure

Depression adversely affects prognosis in heart failure (HF) patients. Inflammation is indicated as potential biological pathway in this co-morbidity. Since increased levels of the cytokine Neutrophil Gelatinase-Associated Lipocalin (NGAL) are predictive for HF prognosis, and recently indicated in patients with major depression, this study examined the association of serum NGAL levels with symptoms of depression in patients with HF. Serum NGAL levels were measured in 104 patients with HF (left ventricular ejection fraction, LVEF⩽40). Depression, evaluated using the Beck Depression Inventory (BDI; total score, somatic and cognitive component), and the Hamilton Depression Rating scale (HAMD), at baseline and 12months follow-up, was associated with NGAL levels using mixed model analysis. Analyses were adjusted for demographics measures, disease severity indicators, inflammation, comorbidity and medication. Increased serum NGAL levels were significantly associated with depression measured by HAMD (baseline: r=0.25, p<.05) and BDI (baseline: r=0.22, p<.05; 12months: r=0.37, p<.01). This association remained significant after adjustment for covariates; age, sex, time, LVEF, and creatinine (HAMD, t=2.01, p=.047; BDI, t=2.28, p=.024). NGAL was significantly associated with somatic- (p=0.004), but not cognitive depressive symptoms (p=0.32). NGAL levels were associated with the experienced HF-related functional limitations (6min walk test), rather than the severity of cardiac dysfunction (LVEF). This study indicates that depression in patients with chronic HF is associated with elevated NGAL levels, independent of clinical severity of the underlying disease.

Effect of glomerular filtration rate impairment on diagnostic performance of neutrophil gelatinase-associated lipocalin and B-type natriuretic peptide as markers of acute cardiac and renal failure in chronic kidney disease patients

INTRODUCTION

Cardio-renal syndromes are characterized by the impairment of cardiac and renal functions. Plasma and urinary neutrophil gelatinase-associated lipocalin (NGAL), and plasma B-type natriuretic peptide (BNP) are markers of acute kidney injury (AKI) and heart failure (HF), respectively.

METHODS

GFR (99mTc-DTPA), plasma BNP, and plasma and urinary concentrations of NGAL were measured in 310 clinically stable CKD patients, at functional stages from 1 to 5. Serum and urinary low-molecular-weight proteins cystatin C and β2-microglobulin, and urinary tubular enzymes were measured for comparison. Plasma BNP, NGAL, cystatin C and β2-microglobulin were measured also in 31 maintenance hemodialysis patients.

RESULTS

Plasma NGAL increased with the reduction of GFR in CKD patients from stage 2. In the different CKD stages modest differences were found for BNP values. Urinary NGAL increased slightly but significantly in patients at CKD stages 4 and 5, similarly to urinary cystatin C and β2-microglobulin. In maintenance hemodialysis patients, plasma NGAL and BNP were markedly increased, and high-flux hemodialysis significantly decreased their plasma concentrations.

CONCLUSIONS

Plasma NGAL increases markedly with the reduction in GFR, generating a very high number of false positive diagnoses of AKI in stable CKD patients. The grade of GFR impairment and the cause of kidney disease have a lower effect on urinary NGAL and on plasma BNP. In any case, specific reference values of NGAL and BNP should be used in chronic kidney disease patients, according to their functional stage, when assessing acute kidney injury, heart failure, and cardio-renal syndromes in patients with impaired GFR.

Cardiorenal syndrome

Cardiorenal syndrome (CRS) includes a broad spectrum of diseases within which both the heart and kidneys are involved, acutely or chronically. An effective classification of CRS in 2008 essentially divides CRS in two main groups, cardiorenal and renocardiac CRS, based on primum movens of disease (cardiac or renal); both cardiorenal and renocardiac CRS are then divided into acute and chronic, according to onset of disease. The fifth type of CRS integrates all cardiorenal involvement induced by systemic disease. This article addresses the pathophysiology, diagnosis, treatment, and outcomes of the 5 distinct types of CRS.

Prognostic impact of renal function in precapillary pulmonary hypertension

BACKGROUND

Impairment of renal function is associated with adverse outcome in various diseases. Patients with pulmonary hypertension (PH) show diminished cardiac function and organ perfusion. The aim of this study was to investigate the associations between renal function and both haemodynamic parameters and long-term survival in patients with PH.

METHODS

Blood was collected from 64 patients with PH (Dana Point class 1, 3 and 4) during right heart catheterization, and plasma was prepared. Creatinine, blood urea nitrogen (BUN), cystatin C, neutrophil-gelatinase-associated lipocalin (NGAL), fibroblast growth factor 23 (FGF-23) and α-Klotho levels were determined, and glomerular filtration rate (GFR) was estimated (eGFR). Parameters were evaluated using c-statistics and dichotomized for survival analysis based on receiver operating characteristic curves.

RESULTS

The median follow-up time was 9.92 years with all-cause mortality as the primary end-point. Elevated BUN, cystatin C and creatinine levels were associated with decreased survival, with hazard ratios (HRs) of 3.237, 4.514 and 2.006, respectively, and equivalent performance according to c-statistics. Estimating GFR by CKD-EPI, MDRD and Cockcroft-Gault formulas resulted in HRs of 2.942, 2.694 and 3.306, respectively. Amongst these formulas, eGFR (Cockcroft-Gault) had the highest c-statistics of 0.674. There was a correlation between BUN and both cardiac index (τ = -0.39) and pulmonary vascular resistance index (τ = 0.249), whereas eGFR (CKD-EPI) was correlated with cardiac index (τ = 0.225). No correlations between either BUN or eGFR and right atrial pressure (RAP) were observed. NGAL, FGF-23 and α-Klotho had no prognostic impact or association with haemodynamic parameters.

CONCLUSION

Comparison of markers of renal function for prognosis in PH demonstrated superiority of creatinine, cystatin C and BUN over NGAL, FGF-23 and α-Klotho. Minor decreases in eGFR influence long-term prognosis, and measurement of cystatin C levels might be useful to detect renal impairment in patients with a normal serum concentration of creatinine. Renal function in patients with PH is linked to cardiac index rather than RAP.

Neutrophil gelatinase associated lipocalin in acute kidney injury

BACKGROUND

Neutrophil gelatinase-associated lipocalin (NGAL) is a member of the lipocalin family of proteins. Usually, NGAL is produced and secreted by kidney tubule cells at low levels, but the amount produced and secreted into the urine and serum increases dramatically after ischemic, septic, or nephrotoxic injury of the kidneys. The purpose of our review article is to summarize the role of NGAL in acute kidney injury (AKI), emergent, and intensive care.

METHODS

A PubMed search was performed (only English-language articles concerning human subjects were considered) using each of the following search term combinations: neutrophil gelatinase-associated lipocalin OR NGAL and acute kidney injury OR AKI; cardiac surgery; heart failure OR cardiology; intensive care; emergency department OR emergency medicine; nephropathy OR nephrotoxicity and transplantation.

RESULTS

The results of our search yielded 339 articles. Of the 339 articles, 160 were eligible for review based on the predefined criteria for inclusion.

CONCLUSION

Based on the evidence reviewed, it is clear that patient NGAL level is an appropriate, sensitive, and specific early biomarker of AKI caused by a variety of different etiologies. It is advised that a multidisciplinary group of experts come together to make recommendations and propose a consensus of clinical procedures to advance the most efficacious NGAL monitoring protocol for early detection and treatment of patients with AKI.

Urinary neutrophil gelatinase-associated lipocalin as a predictor of cardiovascular events in patients with chronic kidney disease

Chronic kidney disease (CKD) is associated with an increased risk of cardiovascular (CV) events. Recently, elevated neutrophil gelatinase-associated lipocalin (NGAL) levels have been reported in patients with heart failure, coronary heart disease, or stroke. Our aim was to assess urinary NGAL as a predictor of CV events in patients with CKD. This was a prospective observational cohort study of 404 patients with predialysis CKD. CV events were defined as CV death, acute coronary syndrome, hospitalization for worsening heart failure, stroke and dissection of aorta. During a mean follow-up period of 33 months, 77 CV events (19.1 %) occurred. After adjustment for gender, age, diabetes, previous cardiovascular disease, urinary albumin/creatinine ratio (UACR), estimated glomerular filtration rate, hemoglobin, and high-sensitivity C-reactive protein, patients with the other quartiles of urinary NGAL had significantly higher risk of CV events compared with patients with the lowest quartile (hazard ratio (HR) 2.81, 95 % confidence interval (CI) 1.01-7.81, P = 0.047 for Q2, HR 3.31, 95 % CI 1.22-9.00, P = 0.019 for Q3, and HR 3.27, 95 % CI 1.15-9.29, P = 0.026 for Q4). Regarding the combination of urinary NGAL with UACR, we also stratified patients into four groups according to whether the level of each marker was above or below the median (61.8 μg per gram creatinine (gCr) for NGAL and 351.1 mg/gCr for UACR). Four-year CV event-free survival rates were 89.2, 79.6, 71.8, and 51.5 % in order for the four respective groups (P < 0.0001). Elevated urinary NGAL was able to predict future CV events in CKD patients, and had incremental predictive value with elevated UACR.

Prognostic value of plasma neutrophil gelatinase-associated lipocalin for mortality in patients with heart failure

BACKGROUND

In patients with heart failure, renal dysfunction is associated with a poor outcome. We aimed to assess the prognostic value of plasma neutrophil gelatinase-associated lipocalin (NGAL), a novel marker of renal tubular damage, in patients with heart failure with or without renal dysfunction, and compare it with 2 frequently used biomarkers of chronic kidney disease.

METHODS AND RESULTS

Plasma NGAL, estimated glomerular filtration rate (eGFR), and cystatin C were assessed in 562 patients with heart failure. Chronic kidney disease was defined as eGFR<60 mL/min per 1.73 m2. Outcome was all-cause mortality at 36 months. Mean age was 71±11 years, 61% were men, and 97% were in New York Heart Association functional class II/III. Mean baseline eGFR was 54±20 mL/min per 1.73 m2, mean cystatin C was 11.2 (7.7-16.2) mg/L, and median plasma NGAL was 85 (60-123) ng/mL. Higher plasma NGAL levels were independently associated with an increased risk of all-cause mortality, in patients with and without chronic kidney disease (hazard ratio [per SD increase in log NGAL]=1.45 [1.22-1.72]; P<0.001 and hazard ratio=1.51 [1.06-2.16]; P=0.023, respectively). Similarly, both in patients with high and low cystatin C (median cut-off), higher plasma NGAL levels were independently associated with an increased risk of all-cause mortality. Moreover, when NGAL was entered in the multivariable risk prediction model, eGFR (P=0.616) and cystatin C (P=0.937) were no longer associated with mortality.

CONCLUSIONS

Plasma NGAL predicts mortality in patients with heart failure, both in patients with and without chronic kidney disease and is a stronger predictor for mortality than the established renal function indices eGFR and cystatin C.

Incorporating common biomarkers into the clinical management of heart failure

Heart failure is a prevalent and costly disease, and its management with polypharmacy is complex. Commonly available biomarkers primarily help to 1) establish or refute the diagnosis of heart failure; 2) help to determine the disease severity; and 3) identify adverse consequences of treatment. Although several of them are commonly ordered (such as electrolytes, renal and liver function), their use is primarily based on broad clinical experience rather than established evidence. The availability of cardiac-specific natriuretic peptide testing has provided an evidence-based breakthrough in our abilities to establish the diagnosis and severity of heart failure, yet the appropriate boundaries to guide management are still in refinement.

The use of biomarkers in the patient with heart failure

Heart failure is a major burden to the health care system in terms of not only cost, but also morbidity and mortality. Appropriate use of biomarkers is critically important to allow rapid identification and optimal risk stratification and management of patients with both acute and chronic heart failure. This review will discuss the biomarkers that have the most diagnostic, prognostic, and therapeutic value in patients with heart failure. We will discuss established biomarkers such as natriuretic peptides as well as emerging biomarkers reflective of myocyte stress, myocyte injury, extracellular matrix injury, and both neurohormonal and cardio-renal physiology.

Incidence and Predictors of End-Stage Renal Disease in Outpatients With Systolic Heart Failure

Background—

Renal dysfunction is an important prognostic factor in heart failure (HF), but whether this dysfunction progresses to end-stage renal disease (ESRD) is unknown. Therefore, we examined incidence and predictors of ESRD in outpatients with HF.

Methods and Results—

Patients with systolic HF were identified in The Danish Heart Failure database and new-onset ESRD from the Danish Registry on Dialysis. Renal function was estimated by The Chronic Kidney Disease Epidemiology Collaboration equation and patients grouped by estimated glomerular filtration rate (eGFR)—group I: ≥60 mL/min per 1.73 m 2 , group II: 30 to 59 mL/min per 1.73 m 2 , group III: 15 to 29 mL/min per 1.73 m 2 , group IV: <15 mL/min per 1.73 m 2 . Cox hazard models for time to ESRD, to death, and the composite end point of ESRD or death were constructed and predictors of ESRD identified. A total of 8204 patients were included in the analyses. Median age was 70 years (Q, 61–77), 28% were women, median left ventricular ejection fraction was 30% (Q, 24–40), and median eGFR was 68 (Q, 51–85) mL/min per 1.73 m 2 . Forty-one patients developed ESRD (1.3/1000 patient-years). Baseline eGFR group II ( P <0.001), eGFR group III ( P <0.001), eGFR group IV ( P <0.001), uncontrolled hypertension ( P =0.049), need of diuretics, and age <60 years ( P =0.016) were associated with time to ESRD.

Conclusions—

ESRD is rare in outpatients with systolic HF and is mainly observed in patients with an eGFR <30 mL/min per 1.73 m 2 . A low eGFR, age <60 years, need of diuretics, and uncontrolled hypertension identify patients with an increased risk for ESRD.

Tubular damage and worsening renal function in chronic heart failure

OBJECTIVES

This study sought to investigate the relationship between tubular damage and worsening renal function (WRF) in chronic heart failure (HF) BACKGROUND: WRF is associated with poor outcome in chronic HF. It is unclear whether urinary tubular markers may identify patients at risk for WRF.

METHODS

In 2,011 patients with chronic HF, we evaluated the ability of urinary tubular markers (N-acetyl-beta-d-glucosaminidase (NAG), kidney injury molecule (KIM)-1, and neutrophil gelatinase-associated lipocalin (NGAL) to predict WRF. Finally, we assessed the prognostic importance of WRF.

RESULTS

A total of 290 patients (14.4%) experienced WRF during follow-up, and WRF was a strong and independent predictor of all-cause mortality and HF hospitalizations (hazard ratio [HR]: 2.87; 95% CI: 2.40 to 3.43; p < 0.001). Patients with WRF had lower baseline glomerular filtration rate and higher KIM-1, NAG, and NGAL levels. In a multivariable-adjusted model, KIM-1 was the strongest independent predictor of WRF (HR: 1.23; 95% CI: 1.09 to 1.39 per log increase; p = 0.001).

CONCLUSIONS

WRF was associated with strongly impaired outcome in patients with chronic HF. Increased level of urinary KIM-1 was the strongest independent predictor of WRF and could therefore be used to identify patients at risk for WRF and poor clinical outcome. (GISSI-HF-Effects of n-3 PUFA and Rosuvastatin on Mortality-Morbidity of Patients With Symptomatic CHF; NCT00336336).

The cardiorenal syndrome: what the cardiologist needs to know

Interactions between the heart and the kidneys are increasingly acknowledged among both cardiologists and nephrologists. The term cardiorenal syndrome now applies to the bidirectional nature of how disease in one organ system affects the function of the other organ system. Cardiovascular disease is a major threat to patients with chronic kidney disease, while renal dysfunction is prevalent in patients with cardiac disease and is a significant predictor of prognosis in cardiac patients. Still, renal patients with cardiac disease have largely been excluded from the clinical trials that have been the basis of modern cardiologic treatment. In this review, the current understanding of the pathophysiological mechanisms involved in the cardiorenal syndrome and potential therapeutic implications will be summarized from a nephrologist's point of view. Probably, fragile cardiorenal patients will benefit from an enhanced collaboration between cardiologists and nephrologists to secure the best treatment given under safe conditions.

Clinical utility of biomarkers in chronic kidney disease and chronic heart failure

Biomarkers have an increasingly important clinical role in managing patients with heart failure as well as those with kidney disease, both common conditions with generally poor prognostic outcomes and huge impacts on healthcare economics. For patients with chronic heart failure, biomarkers have become centre place in streamlining diagnostic pathways as well as identifying those with worse prognosis. There is much interest in the role for biomarkers in identifying patients at risk of acute kidney injury, although a number of these currently remain as research tools or are in the early stages of evaluation in clinical practice. Patients with cardiorenal syndrome represent a particular challenge to the clinician, and recent studies have suggested a valuable clinical role for certain biomarkers in this setting, either on their own or in combination. This paper will focus on biomarkers with a current clinical role in patients with cardiorenal disease (natriuretic peptides and neutrophil gelatinase-associated lipocalin), although brief reference will be made to other biomarkers with potential future application.

The prevalence of chronic kidney disease in a primary care setting: a Swiss cross-sectional study

Chronic kidney disease (CKD) often remains clinically silent and therefore undiagnosed until a progressed stage is reached. Our aim was to estimate the prevalence of CKD in a primary care setting in Switzerland. A multicenter, cross-sectional study with randomly selected general practitioners was performed. Adults visiting their general physician’s cabinet during defined periods were asked to participate. Baseline information was reported on a questionnaire, urine and blood samples were analyzed in a central laboratory. Renal status was assessed using the Kidney Disease: Improving Global Outcomes (KDIGO) classification. Extrapolation of results to national level was adjusted for age and gender. One thousand individuals (57% females) with a mean age of 57±17 years were included. Overall, 41% of the patients had normal estimated glomerular filtration rate (eGFR) and albumin creatinine ratio (ACR), whereas 36% of the subjects had slightly reduced excretory renal function with physiological albuminuria based on normal ACR. Almost one fourth of the subjects (23%) had either a substantially reduced eGFR or high levels of ACR. About 10% of the patients had a substantially reduced eGFR of <60 ml/min/1.73 m², and 17% showed relevant proteinuria (ACR >30 mg/g creatinine). Extrapolation to national level suggests that about 18% of primary care patients may suffer from CKD. CKD prevalence in a primary care population is therefore high, and preventive interventions may be advisable, in particular as CKD prevalence is likely to rise over the next decades.

Animal models of cardiorenal syndrome: a review

The incidence of heart failure and renal failure is increasing and is associated with poor prognosis. Moreover, these conditions do often coexist and this coexistence results in worsened outcome. Various mechanisms have been proposed as an explanation of this interrelation, including changes in hemodynamics, endothelial dysfunction, inflammation, activation of renin-angiotensin-aldosterone system, and/or sympathetic nervous system. However, the exact mechanisms initializing and maintaining this interaction are still unknown. In many experimental studies on cardiac or renal dysfunction, the function of the other organ was either not addressed or the authors failed to show any decline in its function despite histological changes. There are few studies in which the dysfunction of both heart and kidney function has been described. In this review, we discuss animal models of combined cardiorenal dysfunction. We show that translation of the results from animal studies is limited, and there is a need for new and better models of the cardiorenal interaction to improve our understanding of this syndrome. Finally, we propose several requirements that a new animal model should meet to serve as a tool for studies on the cardiorenal syndrome.

Renal dysfunction in acute heart failure: epidemiology, mechanisms and assessment

Renal dysfunction is often present and/or worsens in patients with heart failure and this is associated with increased costs of care, complications and mortality. The cardiorenal syndrome can be defined as the presence or development of renal dysfunction in patients with heart failure. Its mechanisms are likely related to low cardiac output, increased venous congestion and renal venous pressure, neurohormonal and inflammatory activation and local changes, such as adenosine release. Many drugs, including loop diuretics, may contribute to worsening renal function through the activation of some of these mechanisms. Renal damage is conventionally defined by the increase in creatinine and blood urea nitrogen blood levels. However, these changes may be not related with renal injury or prognosis. New biomarkers of renal injury seem promising but still need to be validated. Thus, despite the epidemiological evidence, we are still lacking of satisfactory tools to assess renal injury and function and its prognostic significance.

Current and novel renal biomarkers in heart failure

Renal function is the most important predictor of clinical outcome in heart failure (HF). It is therefore essential to have accurate and reliable measurement of renal function and early specific markers of renal impairment in patients with HF. Several renal functional entities exist, including glomerular filtration (GFR), glomerular permeability, tubulointerstitial damage, and endocrine function. Different markers have been studied that can be used to determine changes and the effect of treatment in these entities. In the present review, we summarize current and novel markers that give an assessment of renal function and prognosis in the setting of acute and chronic HF.

Urinary neutrophil gelatinase-associated lipocalin (NGAL) is associated with mortality in a community-based cohort of older Swedish men

OBJECTIVE

Neutrophil gelatinase-associated lipocalin (NGAL) indicates tubular kidney damage, neutrophil activation and possibly atherogenesis, however the prospective association between urinary NGAL (u-NGAL) and cardiovascular death in the community is not known.

METHODS

This study evaluates the association between urinary and serum NGAL and mortality in a Swedish population of 597 men aged 78 years. During the study (median follow-up 8.1 years) 261 men died, 90 of cardiovascular causes.

RESULTS

U-NGAL was associated with increased all-cause and cardiovascular mortality (HR 2.0 for quartile 4 vs. quartile 1, 95% CI 1.0-4.0, P < 0.05) in Cox regression models independently of cardiovascular risk factors, CRP and cystatin C estimated glomerular filtration rate (eGFRCysC) but not urinary Albumin (u-Alb). A combination of low eGFRCysC (≤60 mL/min), high u-Alb (≥3 mg/mmol Cr) and high u-NGAL (≥1.19 μg/mmol Cr) was associated with a 9-fold increased cardiovascular mortality (P < 0.001) and a 3-fold increased all-cause mortality (P < 0.001). Serum NGAL was associated with increased all-cause mortality risk independent of other cardiovascular risk factors (HR 1.4 for quartile 4 vs.1, 95% CI 1.0-1.9, P < 0.05) but not after adjustment with CRP, eGFRCysC or u-Alb.

CONCLUSION

This community study is the first to show that the tubular kidney biomarker u-NGAL associated with increased cardiovascular and all-cause mortality independent of cardiovascular risk factors and glomerular filtration. Additional research is needed to evaluate the utility of NGAL in clinical practice.

Neutrophil gelatinase-associated lipocalin as a biomarker of cardiovascular disease: a systematic review

BACKGROUND

Neutrophil gelatinase-associated lipocalin (NGAL) is a biomarker of acute kidney injury (AKI). Recently, elevated NGAL levels have also been reported in heart failure, coronary heart disease, and stroke. Other studies demonstrate that NGAL is upregulated in failing myocardium and in atherosclerotic plaque. Our aim was to synthesize the current evidence on NGAL and cardiovascular disease (CVD), and to clarify the prognostic significance of systemic NGAL levels in CVD.

METHODS

We performed a systematic review to identify experimental and human studies on NGAL and CVD. We excluded articles which specifically dealt with AKI or renal endpoints.

RESULTS

We identified 22 studies, including both animal and human data. NGAL is highly expressed in the heart, both in failing myocardium and myocarditis, and is also expressed in atherosclerotic plaques. Areas of co-localization of NGAL and matrix metalloproteinase (MMP)-9 exhibited increased MMP-9 proteolytic activity. Systemic NGAL levels correlated with renal function and severity of CVD in several, but not all, studies. An association between elevated systemic NGAL levels and clinical outcomes (e.g., death, hospital readmissions) were reported in six CVD studies, but these had limited adjustment for potential confounders.

CONCLUSIONS

There is ample literature to support a putative role of NGAL in the pathophysiology of CVD, but at present there is insufficient data regarding the clinical utility of systemic NGAL levels in the management of CVD. Available evidence regarding NGAL as a predictor of outcomes in CVD is very limited.

Novel Biomarkers for Cardio-renal Syndrome

Cardio-renal syndrome (CRS) is a frequent and life-threatening syndrome. It is a disorder of the heart and kidneys in which acute or chronic dysfunction in one organ may induce acute or chronic dysfunction in the other organ. Acute kidney injury (AKI) is strongly associated with increased morbidity and mortality in patients with CRS. Early detection of renal dysfunction is not possible using the traditional marker, serum creatinine, and therefore efforts to explore possible biomarkers for early detection of AKI are being made. Apart from predicting AKI, several biomarker studies also identified predictors for poor prognosis such as the need for renal replacement therapy (RRT) or death. It is possible that biomarkers can become risk factors in an improvement of clinical outcomes of CRS. Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in patients with renal dysfunction and the treatment for this disease can be modified based on cardiac biomarkers. In addition to natriuretic peptides, which are established cardiac markers, several new biomarkers have been identified and may play important roles in CRS. In this review, we will briefly summarize the literature on novel renal and cardiac biomarkers and discuss their potential roles in the clinical outcome of CRS.

The relevance of congestion in the cardio-renal syndrome

Worsening renal function (WRF) during the treatment of acute decompensated heart failure (ADHF) occurs in up to a third of patients and is associated with worse survival. Venous congestion is increasingly being recognized as a key player associated with WRF in ADHF. Understanding the hemodynamic effects of venous congestion and the interplay between venous congestion and other pathophysiological factors such as raised abdominal pressure, endothelial cell activation, anemia/ iron deficiency, sympathetic overactivity, and stimulation of the renin-angiotensin-aldosterone system will help in devising effective management strategies. Early recognition of venous congestion through novel techniques such as bioimpedance measurements and remote monitoring of volume status combined with customized diuretic regimens may prevent venous congestion and perhaps avoid significant WRF.

Cardiorenal biomarkers in acute heart failure

Managing patients with heart failure (HF) is a challenging task within itself, but the presence of associated worsening renal function can greatly increase mortality and morbidity. Early diagnosis and treatment is the key to prevent re-hospitalizations and reduce healthcare costs. Biomarkers have long been established as highly sensitive and specific tools in diagnosing and prognosticating patients with HF. Reflecting distinct pathophysiological events and ongoing cellular insult, biomarkers have been proven superior to conventional laboratory tests. Availability of better assays and rapid analysis has allowed the use of biomarkers as point-of-care tests in the emergency department and at the patient's bed-side. Acute HF patients often go on to develop worsening renal function, termed as acute cardiorenal syndrome. The growing breadth of studies has shown the implications of combining multiple biomarkers to better chart outcomes and produce desirable results in such patients.

Emerging clinical and experimental evidence for the role of lipocalin-2 in metabolic syndrome

The inflammatory state, which is associated with the current pandemic of obesity, has been established as an important contributing pathogenic factor to the increased prevalence of the so-called metabolic syndrome. Many studies have focused on the contribution of various adipokines to this phenomenon, and in the present study, we provide an update on the emerging evidence that the pro-inflammatory factor, lipocalin-2, might influence various aspects of metabolic syndrome. Previous reports indicate a positive correlation of serum lipocalin-2 with fasting glucose, the homeostasis model assessment of insulin resistance index, and the inflammatory marker high-sensitivity C-reactive protein, even after adjustment for body mass index, suggesting that it is an independent risk factor for insulin resistance, diabetes, and inflammation. Direct analysis of lipocalin-2 action now also shows effects on peripheral metabolism and on cardiovascular function. A better understanding of how lipocalin-2 is regulated locally and systemically is crucial for adding to our understanding of the pathogenesis of metabolic syndrome, and to uncover potential new avenues for therapeutic approaches.

The role of the kidney in heart failure

Renal dysfunction is common in patients with heart failure and is associated with high morbidity and mortality. Cardiac and renal dysfunction may worsen each other through multiple mechanisms such as fluid overload and increased venous pressure, hypo-perfusion, neurohormonal and inflammatory activation, and concomitant treatment. The interaction between cardiac and renal dysfunction may be critical for disease progression and prognosis. Renal dysfunction is conventionally defined by a reduced glomerular filtration rate, calculated from serum creatinine levels. This definition has limitations as serum creatinine is dependent on age, gender, muscle mass, volume status, and renal haemodynamics. Changes in serum creatinine related to treatment with diuretics or angiotensin-converting enzyme inhibitors are not necessarily associated with worse outcomes. New biomarkers might be of additional value to detect an early deterioration in renal function and to improve the prognostic assessment, but they need further validation. Thus, the evaluation of renal function in patients with heart failure is important as it may reflect their haemodynamic status and provide a better prognostic assessment. The prevention of renal dysfunction with new therapies might also improve outcomes although strong evidence is still lacking.

Prevalence of chronic kidney disease and progression of disease over time among patients enrolled in the Houston West Nile virus cohort

INTRODUCTION

In experimental models of West Nile virus (WNV) infection, animals develop chronic kidney infection with histopathological changes in the kidney up to 8-months post-infection. However, the long term pathologic effects of acute infection in humans are largely unknown. The purpose of this study was to assess renal outcomes following WNV infection, specifically the development of chronic kidney disease (CKD).

METHODS

In a cohort of 139 study participants with a previous diagnosis of WNV infection, we investigated the prevalence of CKD using the Kidney Disease Outcomes Quality Initiative (KDOQI) criteria based on the Modification of Diet in Renal Disease (MDRD) formula and urinary abnormalities, and assessed various risk factors and biomarkers.

RESULTS

Study participants were primarily male (60%) and non-Hispanic white (86%) with a mean age of 57 years. Most (83%) were four to nine years post-infection at the time of this study. Based on the KDOQI definition, 40% of participants had evidence of CKD, with 10% having Stage III or greater and 30% having Stage I-II. By urinary dipstick testing, 26% of patients had proteinuria and 23% had hematuria. Plasma NGAL levels were elevated in 14% of participants while MCP-1 levels were increased in 12%. Over 1.5 years, the average change in eGFR was -3.71 mL/min/1.73 m(2). Only a history of Neuroinvasive WNV disease was independently associated with CKD following multivariate analysis.

DISCUSSION

We found a high prevalence of CKD after long term follow-up in a cohort of participants previously infected with WNV. The majority of those with CKD are in Stage I-II indicating early stages of renal disease. Traditional risk factors were not associated with the presence of CKD in this population. Therefore, clinicians should regularly evaluate all patients with a history of WNV for evidence of CKD.