The coexistence of diabetic retinopathy and diabetic nephropathy is associated with worse kidney outcomes.

Background: Up to 50-60% of patients with diabetes have non-diabetic kidney disease (NDKD) on kidney biopsy. Diabetic retinopathy (DR) is a microvascular complication of diabetes frequently associated with diabetic nephropathy (DN). The objective of the current study was to investigate the kidney outcomes and survival in patients with biopsy diagnoses of DN and NDKD according to the presence of DR. Methods: We conducted an observational, multicentre and retrospective study of the pathological findings of renal biopsies from 832 consecutive patients with diabetes from 2002 to 2014 from 18 nephrology departments. The association of DR with kidney replacement therapy (KRT) or survival was assessed by Kaplan-Meier and Cox regression analyses. Results: Of 832 patients with diabetes and renal biopsy, 768 had a retinal examination and 221/768 (22.6%) had DR. During a follow-up of 10 years, 288/760 (37.9%) patients with follow-up data needed KRT and 157/760 (20.7%) died. The incidence of KRT was higher among patients with DN (alone or with NDKD) and DR [103/175 (58.9%)] than among patients without DR [88/216 (40.7%), P < .0001]. The incidence of KRT was also higher among patients with only NDKD and DR than among those without DR [18/46 (39.1%) versus 79/331 (23.9%), P < .0001]. In multivariate analysis, DR or DN were independent risk factors for KRT {hazard ratio [HR] 2.48 [confidence interval (CI) 1.85-3.31], P < .001}. DN (with or without DR) was also identified as an independent risk factor for mortality [HR 1.81 (CI 1.26-2.62), P = .001]. Conclusions: DR is associated with a higher risk of progression to kidney failure in patients with histological DN and in patients with NDKD.

Targeting the TWEAK-Fn14 pathway prevents dysfunction in cardiac calcium handling after acute kidney injury.

Heart and kidney have a closely interrelated pathophysiology. Acute kidney injury (AKI) is associated with significantly increased rates of cardiovascular events, a relationship defined as cardiorenal syndrome type 3 (CRS3). The underlying mechanisms that trigger heart disease remain, however, unknown, particularly concerning the clinical impact of AKI on cardiac outcomes and overall mortality. Tumour necrosis factor-like weak inducer of apoptosis (TWEAK) and its receptor fibroblast growth factor-inducible 14 (Fn14) are independently involved in the pathogenesis of both heart and kidney failure, and recent studies have proposed TWEAK as a possible therapeutic target; however, its specific role in cardiac damage associated with CRS3 remains to be clarified. Firstly, we demonstrated in a retrospective longitudinal clinical study that soluble TWEAK plasma levels were a predictive biomarker of mortality in patients with AKI. Furthermore, the exogenous application of TWEAK to native ventricular cardiomyocytes induced relevant calcium (Ca2+ ) handling alterations. Next, we investigated the role of the TWEAK-Fn14 axis in cardiomyocyte function following renal ischaemia-reperfusion (I/R) injury in mice. We observed that TWEAK-Fn14 signalling was activated in the hearts of AKI mice. Mice also showed significantly altered intra-cardiomyocyte Ca2+ handling and arrhythmogenic Ca2+ events through an impairment in sarcoplasmic reticulum Ca2+ -adenosine triphosphatase 2a pump (SERCA2a ) and ryanodine receptor (RyR2 ) function. Administration of anti-TWEAK antibody after reperfusion significantly improved alterations in Ca2+ cycling and arrhythmogenic events and prevented SERCA2a and RyR2 modifications. In conclusion, this study establishes the relevance of the TWEAK-Fn14 pathway in cardiac dysfunction linked to CRS3, both as a predictor of mortality in patients with AKI and as a Ca2+ mishandling inducer in cardiomyocytes, and highlights the cardioprotective benefits of TWEAK targeting in CRS3. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Oral Sodium Chloride in the Prevention of Contrast-Associated Acute Kidney Injury in Elderly Outpatients: The PNIC-Na Randomized Non-Inferiority Trial.

OBJECTIVE: We aimed to test the non-inferiority of oral versus intravenous hydration in the incidence of contrast-associated acute kidney injury (CA-AKI) in elderly outpatients undergoing a contrast-enhanced computed tomography (CE-CT) scan. METHODS: PNIC-Na (NCT03476460) is a phase-2, single-center, randomized, open-label, non-inferiority trial. We included outpatients undergoing a CE-CT scan, >65 years having at least one risk factor for CA-AKI, such as diabetes, heart failure, or an estimated glomerular filtration rate (eGFR) of 30-59 mL/min/1.73 m². Participants were randomized (1:1) to oral sodium-chloride capsules or intravenous hydration. The primary outcome was an increase in serum creatinine >0.3 mg/dL or a reduction in eGFR >25% within 48 h. The non-inferiority margin was set at 5%. RESULTS: A total of 271 subjects (mean age 74 years, 66% male) were randomized, and 252 were considered for the main analysis (per-protocol). A total of 123 received oral hydration and 129 intravenous. CA-AKI occurred in 9 (3.6%) of 252 patients and 5/123 (4.1%) in the oral-hydration group vs. 4/129 (3.1%) in the intravenous-hydration group. The absolute difference between the groups was 1.0% (95% CI -4.8% to 7.0%), and the upper limit of the 95% CI exceeded the pre-established non-inferiority margin. No major safety concerns were observed. CONCLUSION: The incidence of CA-AKI was lower than expected. Although both regimens showed similar incidences of CA-AKI, the non-inferiority was not shown.

Interplay between mineral bone disorder and cardiac damage in acute kidney injury: from Ca2+ mishandling and preventive role of Klotho in mice to its potential mortality prediction in human.

Biomarkers of mineral bone disorders (MBD) including phosphorus, fibroblast growth factor (FGF)-23 and Klotho are strongly altered in patients with acute kidney injury (AKI) who have high cardiac outcomes and mortality rates. However, the crosslink between MBD and cardiac damage after an AKI episode still remains unclear. We tested MBD and cardiac biomarkers in an experimental AKI model after 24 or 72 hours of folic acid injection and we analyzed structural cardiac remodeling, intracellular calcium (Ca2+) dynamics in cardiomyocytes and cardiac rhythm. AKI mice presented high levels of FGF-23, phosphorus and cardiac troponin T and exhibited a cardiac hypertrophy phenotype accompanied by an increase in systolic Ca2+ release 24 hours after AKI. Ca2+ transients and contractile dysfunction were reduced 72 hours after AKI while diastolic sarcoplasmic reticulum Ca2+ leak, pro-arrhythmogenic Ca2+ events and ventricular arrhythmias were increased. These cardiac events were linked to the activation of the calcium/calmodulin-dependent kinase II pathway through the increased phosphorylation of ryanodine receptors and phospholamban specific sites after AKI. Cardiac hypertrophy and the altered intracellular Ca2+ dynamics were prevented in transgenic mice overexpressing Klotho after AKI induction. In a translational retrospective longitudinal clinical study, we determined that combining FGF-23 and phosphorus with cardiac troponin T levels achieved a better prediction of mortality in AKI patients at hospital admission. Thus, monitoring MBD and cardiac damage biomarkers could be crucial to prevent mortality in AKI patients. In this setting, Klotho might be considered as a new cardioprotective therapeutic tool to prevent deleterious cardiac events in AKI conditions.

Total renal volume and renal function after radical nephrectomy in renal neoplasm.

INTRODUCTION: The reduction of renal mass after radical nephrectomy (RN) for renal neoplasm, could be associated with compensatory hypertrophy of the contralateral kidney. The capacity of compensation will determine the renal function (RF) evolution. Measuring of total renal volume (TRV) of the remaining kidney pre and post RN can help assess the RF evolution. OBJECTIVES: To determine the correlation between TRV pre and post nephrectomy (a year of follow-up) with RF. MATERIALS AND METHODS: A retrospective cohort study was carried out in 47 patients who had undergone RN from 2014 to 2018, due to renal cell carcinoma (confirmed by histopathology). The TRV was calculated, pre and post (a year of follow-up) RN, using ellipsoid formula equation, which were compared with clinical and analytical data. The results were analyzed by multivariate linear logistic models. RESULTS: The median age at the time of RN was 70 years old (range, 40-88 years). Most of them were men, 66%. The estimated glomerular filtration rate (eGFR) pre and post nephrectomy was 78 (40-100) and 53.3ml/min/m2 (30-90) respectively (p=0.01). The TRV pre and post-nephrectomy was 168.2ml (100.4-257.2) and 187.8ml (115.5-273.1) respectively (p=0.001). The pre-nephrectomy eGFR (ß=0.62; p=0.034) and the TRV (ß=1.08; p<0.0001) were positively correlated with the post-nephrectomy TRV, while the eGFR at year of follow-up was correlated negatively (ß=-1.18; p=0.047). CONCLUSIONS: The measurement of pre and post nephrectomy TRV can help to predict renal function evolution at a year of follow-up.

Risk factors for non-diabetic renal disease in diabetic patients.

BACKGROUND: Diabetic patients with kidney disease have a high prevalence of non-diabetic renal disease (NDRD). Renal and patient survival regarding the diagnosis of diabetic nephropathy (DN) or NDRD have not been widely studied. The aim of our study is to evaluate the prevalence of NDRD in patients with diabetes and to determine the capacity of clinical and analytical data in the prediction of NDRD. In addition, we will study renal and patient prognosis according to the renal biopsy findings in patients with diabetes. METHODS: Retrospective multicentre observational study of renal biopsies performed in patients with diabetes from 2002 to 2014. RESULTS: In total, 832 patients were included: 621 men (74.6%), mean age of 61.7 ± 12.8 years, creatinine was 2.8 ± 2.2 mg/dL and proteinuria 2.7 (interquartile range: 1.2-5.4) g/24 h. About 39.5% (n = 329) of patients had DN, 49.6% (n = 413) NDRD and 10.8% (n = 90) mixed forms. The most frequent NDRD was nephroangiosclerosis (NAS) (n = 87, 9.3%). In the multivariate logistic regression analysis, older age [odds ratio (OR) = 1.03, 95% CI: 1.02-1.05, P < 0.001], microhaematuria (OR = 1.51, 95% CI: 1.03-2.21, P = 0.033) and absence of diabetic retinopathy (DR) (OR = 0.28, 95% CI: 0.19-0.42, P < 0.001) were independently associated with NDRD. Kaplan-Meier analysis showed that patients with DN or mixed forms presented worse renal prognosis than NDRD (P < 0.001) and higher mortality (P = 0.029). In multivariate Cox analyses, older age (P < 0.001), higher serum creatinine (P < 0.001), higher proteinuria (P < 0.001), DR (P = 0.007) and DN (P < 0.001) were independent risk factors for renal replacement therapy. In addition, older age (P < 0.001), peripheral vascular disease (P = 0.002), higher creatinine (P = 0.01) and DN (P = 0.015) were independent risk factors for mortality. CONCLUSIONS: The most frequent cause of NDRD is NAS. Elderly patients with microhaematuria and the absence of DR are the ones at risk for NDRD. Patients with DN presented worse renal prognosis and higher mortality than those with NDRD. These results suggest that in some patients with diabetes, kidney biopsy may be useful for an accurate renal diagnosis and subsequently treatment and prognosis.

Colistimethate sodium and acute kidney injury: Incidence, risk factors, outcome and prognosis of renal function.

BACKGROUND: Colistimethate sodium (CMS) treatment has increased over the last years, being acute kidney injury (AKI) its main drug-related adverse event. Therefore, this study aimed to evaluate the incidence and risk factors associated with AKI, as well as identifying the factors that determine renal function (RF) outcomes at six months after discharge. MATERIALS AND METHODS: This retrospective study included adult septic patients receiving intravenous CMS for at least 48h (January 2007-December 2014). AKI was assessed using KDIGO criteria. The glomerular filtration rate (GFR) was estimated by the 4-variable MDRD equation. Logistic and linear models were performed to evaluate the risk factors for AKI and chronic kidney disease (CKD). RESULTS: Among 126 patients treated with CMS; the incidence of AKI was 48.4%. Sepsis-severe sepsis (OR 8.07, P=0.001), sepsis-septic shock (OR 42.9, P<0.001), and serum creatinine (SCr) at admission (OR 6.20, P=0.009) were independent predictors. Eighty-four patients survived; the main factors for RF evolution at the 6-month follow-up was baseline eGFR (0.58, P<0.001) and at discharge (0.34, P<0.001). Fifty-six percent (34/61) of the patients that developed AKI survived. At six months, 32% had CKD. CONCLUSIONS: The development of AKI in septic patients with CMS treatment was associated with sepsis severity and SCr at admission. Baseline eGFR and eGFR at discharge were and important determinant of the RF at the 6-month follow-up. These predictors may assist in clinical decision making for this patient population.

Protective Role of the Portocaval Shunt in Liver Transplantation.

BACKGROUND: Advances in medical management and surgical technique have resulted in stepwise improvements in early post-transplant survival rates. Modifications in the surgical technique, such as the realization of the portocaval shunt (PCS), could influence survival rates. The aim of this study was to evaluate the mortality rate for 12 months after liver transplantation, analyzing the causes and risk factors related to its development and assessing the impact that PCS could have on them. METHODS: A total of 231 recipients were included in the retrospective, longitudinal, and nonrandomized study. RESULTS: The overall survival of the transplant was 85.2% (197 patients). The most frequent cause of death was infection (38.2%), followed by the multiorgan failure of multiple etiology (23.5%). Most of the risk factors related to mortality correspond to variables of the postoperative period. The results of the multivariate analysis identified the main risk factors for death: the presence of surgical complications and the need for renal replacement therapy. In contrast, the performance of PCS exerted a protective effect, reducing the probability of death by 70%. CONCLUSIONS: Despite the good results obtained in several studies, there is still debate regarding the benefit of its realization. In our study, PCS was a factor associated with a reduction in mortality, with a markedly lower probability of adverse events. However, we agree with other authors on the need for larger and randomized studies to adequately determine the validity of such results.

Pharmacokinetics of Micafungin in Critically Ill Patients Receiving Continuous Venovenous Hemodialysis With High Cutoff Membranes.

BACKGROUND: An optimal antifungal therapy for invasive candidiasis in critically ill patients is essential to reduce the high mortality rates. Acute kidney injury is common, and continuous renal replacement therapies are frequently used. Previous studies have demonstrated a lack of effect from different continuous renal replacement techniques on micafungin clearance. However, the use of high cutoff pore size membranes could potentially allow for the loss of albumin and alter micafungin pharmacokinetics. The objective was to explore the pharmacokinetics of micafungin in critically ill patients undergoing continuous venovenous high cutoff membrane hemodialysis (CVVHD-HCO). METHODS: Prospective observational study performed in critically ill patients treated with 100 mg/d of micafungin and undergoing CVVHD-HCO. CVVHD-HCO sessions were performed using Prisma-Flex monitors and dialyzers with a membrane of polyarylethersulfone of 1.1-m surface area and 45-kDa pore size. Blood samples were collected from arterial prefilter, venous postfilter, and the drainage line ports at 0 (predose), 1, 4, 12, 24 hours after dose, and micafungin concentrations were determined using HPLC-UV. RESULTS: Nine patients (55.6% male; age: 28-80 years) were included. Median (range) of micafungin concentrations in the effluent were <0.2 (<0.2-0.4) mg/L at low (predose) and 0.4 (<0.2-0.7) mg/L at high (1 h) concentrations. The extraction ratio was <12% at each time point. A 2-compartment model best described the time course of plasma concentrations, and body weight was the only covariate that improved the model. CONCLUSIONS: This is the first study demonstrating that CVVHD-HCO does not alter the pharmacokinetics of micafungin, and that standard doses of this antifungal can be used.

Arteriovenous fistulae after renal biopsy: diagnosis and outcomes using Doppler ultrasound assessment.

BACKGROUND: Percutaneous renal biopsy (PRB) is an important technique providing relevant information to guide diagnosis and treatment in renal disease. As an invasive procedure it has complications. Most studies up to date have analysed complications related to bleeding. We report the largest single-center experience on routine Doppler ultrasound (US) assessment post PRB, showing incidence and natural history of arteriovenous fistulae (AVF) post PRB. METHODS: We retrospectively analysed 327 consecutive adult PRB performed at Ramon Cajal University Hospital between January 2011 and December 2014. All biopsies were done under real-time US guidance by a trained nephrologist. Routine Doppler mapping and kidney US was done within 24 h post biopsy regardless of symptoms. Comorbidities, full blood count, clotting, bleeding time and blood pressure were recorded at the time of biopsy. Post biopsy protocol included vitals and urine void checked visually for haematuria. Logistic regression was used to investigate links between AVF, needle size, correcting for potential confounding variables. RESULTS: 46,5% were kidney transplants and 53,5% were native biopsies. Diagnostic material was obtained in 90,5% (142 grafts and 154 native). Forty-seven AVF's (14.37%) were identified with routine kidney Doppler mapping, 95% asymptomatic (n = 45), 28 in grafts (18.4%) and 17 natives (9.7%) (p-value 0.7). Both groups were comparable in terms of comorbidities, passes, cylinders or biopsy yield (p-value NS). 80% were <1 cm in size and 46.6% closed spontaneously in less than 30 days (range 3-151). Larger AVF's (1-2 cm) took a mean of 52 days to closure (range 13-151). Needle size was not statistically significant factor for AVF (p-value 0.71). CONCLUSIONS: Contrary to historical data published, AVF's are a common complication post PRB that can be easily missed. Routine US Doppler mapping performed by trained staff is a cost-effective, non-invasive tool to diagnose and follow up AVF's, helping to assess management.

High temperatures and nephrology: The climate change problem. / Altas temperaturas y nefrología: a propósito del cambio climático.

It is well known that climate change greatly affects human health, even though there are few studies on renal outcomes. Heat waves have been found to increase cardiovascular and respiratory morbidity and mortality, as well as the risk of acute renal failure and hospitalisation due to renal diseases, with related mortality. Recurrent dehydration in people regularly exposed to high temperatures seems to be resulting in an unrecognised cause of proteinuric chronic kidney disease, the underlying pathophysiological mechanism of which is becoming better understood. However, beyond heat waves and extreme temperatures, there is a seasonal variation in glomerular filtration rate that may contribute to the onset of renal failure and electrolyte disorders during extremely hot periods. Although there are few references in the literature, serum sodium disorders seem to increase. The most vulnerable population to heat-related disease are the elderly, children, chronic patients, bedridden people, disabled people, people living alone or with little social contact, and socioeconomically disadvantaged people.

[Acute lithium poisoning: epidemiology, clinical characteristics, and treatment]. / Epidemiología, características clínicas y tratamiento de la intoxicación aguda por litio.

Lithium continues to be the treatment of choice for bipolar disorder. Acute lithium poisoning is a potentially serious event. We present a retrospective observational significative study of episodes of acute lithium poisoning during a 52- month period. Poisoning was defined by a blood lithium concentration of 1.5 mEq/L or higher. We analyzed treatment and epidemiologic and clinical characteristics of 70 episodes were identified (incidence density among treated patients, 1.76 per 100 patient-years). The most frequent cause of lithium poisoning was a concurrent medical condition (46%). Most poisonings were mild (74.2%), but neurologic involvement was identified in 40.3%. Electrocardiographic abnormalities were found in 8 cases. Acute renal failure, found in 23 patients (37.1%), was mild in most cases, although 11 patients required hemodialysis. We concluded that acute lithium poisoning is an uncommon complication, but risk needs to be lowered. Patients should be warned to avoid dosage errors and to take special care during concurrent illnesses and while taking other medications.

El litio sigue siendo el tratamiento de elección en el trastorno bipolar. La intoxicación aguda por litio (IAL) es un cuadro potencialmente grave. Se presenta un estudio observacional, retrospectivo de las IAL observadas durante un periodo de 52 meses. Se definió como IAL cuando se registró una concentración de litio en sangre 1,5 mEq/L. Se analizaron sus características clínicas, epidemiológicas y su tratamiento de 70 episodios de IAL (densidad de incidencia: 1,76 IAL por cada 100 pacientes tratados-año). La causa más frecuente de IAL fue un proceso patológico intercurrente (46%). La mayoría fueron de carácter leve (74,2 %), con sintomatología neurológica en el 40,3%. En 8 IAL hubo alteraciones electrocardiográficas, 23 IAL (37,1%) se asociaron con fracaso renal agudo, la mayoría de carácter leve y 11 precisaron hemodiálisis. Se concluye que la IAL es una complicación infrecuente, pero es necesario disminuir su riesgo advirtiendo al paciente ante la existencia de procesos intercurrentes, errores en la posología o polimedicación.

Anti-neutrophil cytoplasmic antibody-associated vasculitis with renal involvement: Analysis of 89 cases. / Vasculitis asociada a anticuerpos contra el citoplasma de neutrófilo con afectación renal: análisis de 89 casos.

INTRODUCTION: The anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis with renal involvement are associated with high morbi-mortality. In this study we analyse if the prognosis of these diseases have improved in recent years, and which factors influence the outcomes. MATERIAL AND METHODS: Retrospective single-centre observational study, which included all patients diagnosed with microscopic polyangiitis and granulomatosis with polyangiitis with renal involvement in the last 25 years. Demographic, clinical and biochemical parameters of prognostic interest were recorded. The differences between four chronological periods were analysed, along with the determinants of a poor outcome (death or end-stage renal disease). RESULTS: Eighty-nine patients were included (mean age 64±15 years). Sixty-four patients (72%) had microscopic polyangiitis and 25 (28%) granulomatosis with polyangiitis. During the study period, 37 (42%) patients died. Through Cox regression analysis, the best determinants of mortality were the initial glomerular filtration rate (HR 0.911; P=.003), Charlson comorbidity index (HR 1.513; P<.0001) and tobacco smoking (HR 1.816; P=.003). 35% developed end-stage renal disease, and the best determinants (by competing-risk regression) were: initial glomerular filtration rate (sub-hazard ratio [SHR]: 0.791; P<.0001), proteinuria (SHR: 1.313; P<.0001), and smoking status (SHR: 1.848; P=.023). No differences were found in patients' mortality or renal survival between the different study periods. CONCLUSIONS: Prognosis of anti-neutrophil cytoplasm antibodies vasculitis with renal involvement treated with conventional immunosuppressive therapy remains unsatisfactory, and continues to have increased long-term complications and mortality.

Changes in Kidney Function and in the Rate of Tubular Dysfunction After Tenofovir Withdrawal or Continuation in HIV-Infected Patients.

INTRODUCTION: Longitudinal data on the changes in kidney function and tubular abnormalities in case of tenofovir disoproxil fumarate (TDF) withdrawal or continuation are scarce. METHODS: Prospective study of 228 patients receiving TDF, with 3 sequential determinations of serum creatinine, estimated glomerular filtration rate (eGFR), phosphatemia, and different urinary parameters (protein, albumin, phosphaturia, uricosuria, and glycosuria). Changes were analyzed in patients who interrupted TDF as compared to those who continued the same regimen. Proximal renal tubular dysfunction (PRTD) was defined as ≥2 tubular abnormalities. RESULTS: After a median follow-up of 59.5 months, 78 patients (34%) had PRTD, mainly proteinuria (40%) and phosphaturia (61%), and time on TDF explains the severity of tubular alterations and eGFR slopes. In 35 switching patients, there was a rapid and significant eGFR improvement (median +4.1 ml/min per 1.73 m; P = 0.02), leading to a 39%-83% reduction in the prevalence of tubular abnormalities and of PRTD in less than 1 year (66%-39%). In comparison, 193 patients continuing the same regimen for 21.2 months had a small but significant and progressive eGFR decrease (-2.9 mL·min·1.73 m; P < 0.01), and a progressive rise in the prevalence of phosphaturia, uricosuria, and glycosuria (+9%-56%). In linear mixed-effect model, subsequent eGFR impairment was associated with proteinuria and time on TDF, and eGFR improvement with TDF discontinuation. CONCLUSIONS: Our data support the role of use and time on TDF in eGFR decline and tubular dysfunction. In contrast, TDF withdrawal is followed by a rapid and significant, although partial, recovery of eGFR and tubular abnormalities.

Preoperative hydration with 0.9% normal saline to prevent acute kidney injury after major elective open abdominal surgery: A randomised controlled trial.

BACKGROUND: Postoperative acute kidney injury (AKI) is the second leading cause of hospital-acquired AKI. Although many preventive strategies have been tested, none of them has been totally effective. OBJECTIVE: We investigated whether preoperative intravenous hydration with 0.9% normal saline could prevent postoperative AKI. DESIGN: Randomised controlled trial. SETTING: University Ramón y Cajal Hospital, Spain, from June 2006 to February 2011. PATIENTS: Total 328 inpatients scheduled for major elective open abdominal surgery. INTERVENTION: 0.9% normal saline at a dose of 1.5 ml kg h for 12 h before surgery. MAIN OUTCOME MEASURES: The primary outcome was the overall postoperative AKI incidence during the first week after surgery defined by risk, injury, failure, loss, end-stage kidney disease (RIFLE) and AKI network (AKIN) creatinine criteria. Secondary endpoints were the need for ICU admission, renal replacement therapy during the study period and adverse events and hospital mortality during hospital admission. RESULTS: There was no difference in the incidence of AKI between groups: 4.7% in the normal saline group versus 5.0% in the control group and 11.4% in the 0.9% normal saline group versus 7.9% in the control group as assessed by the RIFLE and AKIN creatinine criteria, respectively. Absolute risk reductions (95% confidence interval) were -0.3% (-5.3 to 4.7%) for RIFLE and 3.5% (-10.2 to 3.6%) for AKIN. ICU admission after surgery was required in 44.5% of all participants. Only 2 (0.7%) patients required renal replacement therapy during the first week after surgery. The analysis of adverse events did not show statistically significant differences between the groups except for pain. In our population, 8 (2.4%) patients died during their hospital admission. CONCLUSION: Intravenous hydration with 0.9% normal saline before major open abdominal surgery was not effective in preventing postoperative AKI. No safety concerns were identified during the trial. TRIAL REGISTRATIONS: Clinical trials.gov: NCT00953940 and EUDRA CT: 2005-004755-35.