Acute kidney injury (AKI) and Chronic Kidney Disease (CKD) are global health problems. The pathophysiology of acute-on-chronic kidney disease (AoCKD) is not well understood. We aimed to study clinical outcomes in patients with previous normal (pure acute kidney injury; P-AKI) or impaired kidney function (AoCKD) across the 2012 Kidney Disease Improving Global Outcomes (KDIGO) AKI classification. We performed a retrospective study of patients with AKI, divided into P-AKI and AoCKD groups, evaluating clinical and epidemiological features, distribution across KDIGO-2012 criteria, in-hospital mortality and need for dialysis. One thousand, two hundred and sixty-nine subjects were included. AoCKD individuals were older and had higher comorbidity. P-AKI individuals fulfilled more often the serum creatinine (SCr) ≥ 3.0× criterion in AKI-Stage3, AoCKD subjects reached SCr ≥ 4.0 mg/dL criterion more frequently. AKI severity was associated with in-hospital mortality independently of baseline renal function. AoCKD subjects presented higher mortality when fulfilling AKI-Stage1 criteria or SCr ≥ 3.0× criterion within AKI-Stage3. The relationship between mortality and associated risk factors, such as the net increase of SCr or AoCKD status, fluctuated depending on AKI stage and stage criteria sub-strata. AoCKD patients that fulfil SCr increment rate criteria may be exposed to more severe insults, possibly explaining the higher mortality. AoCKD may constitute a unique clinical syndrome. Adequate staging criteria may help prompt diagnosis and administration of appropriate therapy.

Pre-transplant prognostic scores help to optimize donor/recipient allocation and to minimize organ discard rates. Since most of these scores come from the US, direct application in non-US populations is not advisable. The Survival Benefit Estimator (SBE), built upon the Estimated Post-Transplant Survival (EPTS) and the Kidney Donor Profile Index (KDPI), has not been externally validated. We aimed to examine SBE in a cohort of Spanish kidney transplant recipients. We designed a retrospective cohort-based study of deceased-donor kidney transplants carried out in two different Spanish hospitals. Unadjusted and adjusted Cox models were applied for patient survival. Predictive models were compared using Harrell’s C statistics. SBE, EPTS and KDPI were independently associated with patient survival (p ≤ 0.01 in all models). Model discrimination measured with Harrell’s C statistics ranged from 0.57 (KDPI) to 0.69 (SBE) and 0.71 (EPTS). After adjustment, SBE presented similar calibration and discrimination power to that of EPTS. SBE tended to underestimate actual survival, mainly among high EPTS recipients/high KDPI donors. SBE performed acceptably well at discriminating post-transplant survival in a cohort of Spanish deceased-donor kidney transplant recipients, although its use as the main allocation guide, especially for high KDPI donors or high EPTS recipients requires further testing.

Increased intra-abdominal pressure (IAP) is common among post-surgical patients and may cause organ dysfunction. However, its impact after kidney transplantation on early postoperative complications and graft recovery remains unclear. We designed a prospective, observational cohort study to describe the prevalence and determinants of IAP, as well as its effect on delayed graft function, postoperative complications, and graft recovery. IAP was measured in 205 kidney transplant recipients every 8 h during the first 72 h after surgery using the urinary bladder technique. Intra-abdominal hypertension was defined as IAP ≥ 12 mmHg. Patients were followed for 6 months or until graft failure/death. Mean IAP was 12 ± 3.3 mmHg within the first 24 h. 78% of subjects presented with intra-abdominal hypertension during the first 72 h. Increased IAP was associated with higher renal resistive index [r = 0.213; P = 0.003] and lower urine output [r =  − 0.237; P < 0.001]. 72 h mean IAP was an independent risk factor for delayed graft function [OR: 1.31; 95% CI: 1.13–1.51], postoperative complications [OR: 1.17; 95% CI: 1.03–1.33], and absence of graft function recovery [HR for graft function recovery: 0.94; 95% CI: 0.88–0.99]. Increased IAP was highly prevalent after transplantation and was independently associated with delayed graft function, postoperative complications, and absence of graft function recovery. Routine IAP monitoring should be considered post-transplantation to facilitate early recognition of relevant complications.

BACKGROUND AND AIMS During the last 2 years, we have witnessed several waves of the COVID-19 pandemic characterized by massive infections among the general population, sudden increases in the number of hospitalizations and variable rates of complications and mortality among patients. Acute kidney injury (AKI) has been described as a common and serious complication of COVID-19. However, multiple factors that are involved in the development of this complication have been modified throughout these months, including the appearance of new variants of the virus, the modification of treatment protocols or the advancement of vaccination among the general population. In this study, we aimed to compare the rates of AKI among patients who required admission due to COVID-19 in the first and current (sixth) waves of the pandemic. METHOD Consecutive patients that required admission due to COVID-19 in a tertiary referral hospital during the first (March to May 2020) and current (December 2021) waves of the pandemic were enrolled in the study. Patient characteristics, rates of AKI incidence, 28-day mortality and in-hospital length of stay were compared between groups. Viral infection was confirmed by real-time RT-qPCR in all cases. AKI was defined according to the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines using peak serum creatinine and acute dialysis criteria. Multivariate logistic regression was performed to define potential predictors of AKI. RESULTS Table 1 summarizes demographic and clinical characteristics among enrolled patients. Compared with the current wave, patients admitted during the first wave were older, had higher baseline serum creatinine and lower baseline eGFR. During the first wave, patients presented higher peak serum creatinine values and a higher incidence of in-hospital AKI. Age, male sex, hypertension, diabetes, CKD and pandemic wave were included in multivariate logistic regression analysis as potential predictors of AKI. Only past history of hypertension [OR 2.867; 95% confidence interval (95% CI) 1.279–6.424; P-value: .011] and CKD (OR 2.418; 95% CI 1.237–4.73; P-value: .01) independently predicted AKI in the sample. CONCLUSION Despite multiple changes that have occurred throughout the pandemic, including new treatment protocols, the appearance of new variants of the virus with different clinical profiles or the extensive application of vaccines, these changes have not translated into a significant decrease in the risk of AKI among patients admitted due to COVID-19, which appears to still be conditioned mainly by comorbidities of each patient, including past history of CKD.

Background and Aims Marathon running induces AKI even in adequately prepared and healthy athletes. Heat stress, maintained during more than 2h, has been proposed as one of the leading causes of AKI in marathons runners. Other possible explanations of AKI in this setting could be associated with a reduction of blood supply to the kidneys during the exercise, inadequate hydration or actual structural damage due to microtraumatisms. However, the effect of vigorous exercise of shorter duration on renal function has not been previously described although most risk factors described could also affect kidney function in this type of physical activity. Method 40 volunteer healthy athletes were enrolled in this study. Subjects participated in two physical tests (10km running, 1.5km swimming) which were separated by at least two weeks from each other. These tests were chosen because of their similar oxygen consumption rate and metabolic load. Vitals, blood and urine samples were collected immediately before and after each test. Informed consent was obtained from all participants. The project was funded by Consejería de Sanidad, Junta de Castilla y León (GRS1732/A/18). Results Athletes ranged from 23 to 53 years old. 35% were female. A comparison of hemodynamic and analytical parameters is summarized in Table 1. Running induced a significantly higher rise of serum creatinine and inflammatory markers compared to swimming. Additionally, running caused an increment of serum phosphorus and uric acid levels. Both types of exercise caused a mild increase of urinary albumin/creatinine ratio. Conclusion Compared to swimming, running was associated with a greater rise of serum creatinine, possibly linked to a higher degree of acute inflammation and blood flow redistribution to the muscles. The rise of serum uric acid levels may be associated with increased metabolism and reduced elimination of this molecule while running.