Search Results (37)

Background/Objectives: Differentiating minimal change disease (MCD) from focal segmental glomerulosclerosis (FSGS) remains a diagnostic challenge. We hypothesised that differences in glomerular protein selectivity could translate into distinct serum protein electrophoresis (SPEP) profiles, particularly in severe nephrotic syndrome. Methods: We retrospectively analysed SPEP profiles of adults with biopsy-proven MCD (n = 27), primary FSGS (n = 27), and secondary FSGS (n = 20). Diagnoses were established according to KDIGO guidelines and the Mayo Clinic classification. A severe subgroup was defined by a relative albumin fraction <40% to evaluate patterns in marked hypoalbuminaemia. Results: Secondary FSGS demonstrated significantly higher albumin-to-globulin (A/G) ratios compared with immune-mediated podocytopathies (MCD and primary FSGS), yielding excellent discrimination (AUC > 0.98). In contrast, discriminatory performance between MCD and primary FSGS in the overall cohort was limited (AUC = 0.657). However, within the severe subgroup, the A/G ratio provided clinically meaningful separation (AUC = 0.787). An A/G ratio > 0.49 identified primary FSGS with 86.7% sensitivity and 81.2% specificity. Correlation analysis revealed a strong inverse association between albumin and α2-globulin fractions in immune-mediated podocytopathies (ρ < −0.8), whereas this relationship was attenuated in secondary FSGS (ρ = −0.57). Conclusions: The A/G ratio may represent a practical adjunctive biomarker in the evaluation of podocytopathies. Values > 1.0 strongly favour secondary FSGS, while markedly reduced ratios in severe nephrosis are characteristic of MCD. These findings suggest that differences in glomerular selectivity and the hepatic compensatory response are reflected in routine electrophoretic profiles. Full article

Background/Objectives: Chronic kidney disease (CKD) is a global public health concern, posing significant diagnostic and management challenges in primary care. Estimated glomerular filtration rate (eGFR) is central to CKD staging, yet different estimating equations may yield substantially different stage classifications when applied to the same population. This study aims to compare the eGFR-based CKD stage classification and stage distribution obtained using the Chronic Kidney Disease: Epidemiology Collaboration (CKD-EPI) and Modification of Diet in Renal Disease (MDRD) equations in a large primary care cohort, and to explore the implications of these classification differences for routine use in primary healthcare (PHC). Methods: A cross-sectional analysis was conducted using standardized electronic health records from 117,055 PHC patients in the Matosinhos Health Unit, Portugal, spanning 22 years (2000–2022). CKD staging followed KDIGO guidelines and focused on stages G3–G5, based on the most recent available serum creatinine value. CKD-EPI and MDRD equations were compared overall and across age strata, BMI categories, albuminuria categories (when available), and major comorbidity subgroups, including heart failure, diabetes, and hypertension. Results: Using CKD-EPI, a higher proportion of individuals were classified as CKD stages G3–G5 (9042; 7.73%) compared with MDRD (7686; 6.57%). Classification differences were most pronounced in advanced stages (relative increase with CKD-EPI: G3b +29.4%, G4 +23.6% and G5 +34.4%). Among individuals aged ≥80 years, equation-related classification differences were particularly marked in advanced stages (G5). Similarly, CKD-EPI was associated with higher CKD stage classification rates in high-risk subgroups, including patients with heart failure. Conclusions: Compared with MDRD, CKD-EPI yields a higher proportion of individuals classified into CKD stages, particularly advanced stages and among older adults and high-risk comorbidity subgroups. These findings highlight the substantial impact of equation choice on CKD stage classification in primary care and support the use of CKD-EPI for standardized eGFR reporting, while emphasizing that observed differences reflect classification rather than confirmed CKD diagnosis. Full article

Background: Chronic kidney disease (CKD) and hypertension in adolescence and young adulthood are predisposing factors for cardiovascular and neurological diseases later in life. Serum creatinine levels have been routinely used as a daily practice modality for detecting acute kidney injury (AKI) in patients of all ages, but unfortunately have some limitations, such as their delayed increase during AKI events. An earlier biomarker is needed to detect AKI, notably in the neonatal period. In the present study, we aimed to determine whether neutrophil gelatinase-associated lipocalin (NGAL) could be used as a modality in detecting AKI, not only in children and adults, but also in neonates. Methods: We conducted a prospective-cohort study on preterm neonates with a gestational age of 28–34 weeks at Hasan Sadikin General Hospital, Bandung, and performed serum NGAL and creatinine measurements. Spearman’s rank correlation was used to determine the association between serum NGAL levels and AKI during the first 48 h in these neonates. Serum NGAL was measured using the Elabscience^® Human NGAL ELISA kit; NGAL positivity was defined as serum NGAL > 150 ng/mL for exploratory classification. Results: Serum NGAL measurement showed a better positivity rate in detecting early AKI in neonates than creatinine (KDIGO and nRIFLE), with values of 81.8, 24.7, and 10.4, respectively. Conclusions: NGAL can be used as a modality for detecting AKI earlier in neonates. Full article

Background: The number of patients with chronic coronary syndromes (CCS) is growing, influenced by factors such as increasing life expectancy and prevalence of risk factors. Thus, cardiovascular (CV) disease remains the leading cause of mortality and morbidity worldwide. The main objective of the study was to identify factors associated with long-term survival in patients with chronic coronary syndrome, with a focus on kidney function described by eGFR and albuminuria (assessed by uACR). Methods: The study comprised a total of 257 patients from Bialystok (Poland), aged ≤ 80 years, who 6–18 months earlier were hospitalized for acute coronary syndrome or elective myocardial revascularization. During the 80-month follow-up, 40 (15.6%) patients died, while there was no information about three (1.2%) patients. Patients with preserved eGFR and without albuminuria were characterized by the longest survival, with deterioration of prognosis in groups of progressive kidney dysfunction as defined by KDIGO based on eGFR and uACR. The primary endpoint was death from any cause. Results: Those who survived the 80-month follow-up period were younger (p < 0.001), had a lower waist circumference (p = 0.028), higher diastolic blood pressure (p = 0.026), lower NTproBNP (p < 0.001) and hsCRP (p = 0.001) concentrations, reduced eGFR (p = 0.004) and increased ACR (p = 0.023) were strongly associated with mortality. In logistic regression analysis with stepwise elimination of variables, the strongest factors affecting survival were hemoglobin concentration, left ventricle ejection fraction (LVEF) and hsCRP. Conclusions: Measurement of albuminuria, in addition to eGFR, allows patients to be correctly classified into CV risk categories and facilitates appropriate treatment of patients with CCS. Higher diastolic blood pressure (but still within normal range) was found in patients who later survived 6 years. Measurements of hsCRP, hemoglobin concentration and LVEF help to identify CCS patients at the highest risk of mortality in long-term follow-up. Full article

Background: Acute kidney injury (AKI) is a frequent and prognostically relevant complication of COVID-19. However, reliance on static creatinine values or binary AKI definitions may overlook clinically meaningful early renal dynamics. We evaluated whether early renal function trajectories within the first 24–48 h of hospitalization provide incremental prognostic information. Methods: We conducted a retrospective, single-center cohort study of adults hospitalized with laboratory-confirmed COVID-19 between December 2020 and December 2021. Early renal function patterns were defined using KDIGO-based changes in serum creatinine between admission and 24–48 h, classifying patients as stable, early improvement, or early deterioration. The primary outcome was in-hospital mortality. Multivariable logistic regression adjusted for age, sex, chronic kidney disease, comorbidities, inflammatory burden (C-reactive protein), nutritional status (albumin), pulmonary involvement, and treatment variables. Results: Among 721 patients, 65.2% had stable renal function, 22.5% had early improvement, and 12.3% had early deterioration. In-hospital mortality differed significantly across dynamic patterns (p = 0.007). Mortality was lowest in the stable group (35.1%) and higher in both early improvement (48.1%) and early deterioration (44.9%). After multivariable adjustment, early improvement remained independently associated with higher in-hospital mortality compared with stable renal function (adjusted OR 1.53, 95% CI 1.03–2.28), while early deterioration showed a directionally similar but non-significant association. Early improvement was also associated with higher AKI burden and increased need for acute de novo hemodialysis. Conclusions: Early renal function change patterns within the first 24–48 h of hospitalization carry prognostic value beyond static creatinine measures. Apparent early creatinine improvement may reflect recovery from prior injury or systemic instability rather than true renal recovery, identifying a subgroup at heightened risk. Classification based on early renal function assessment may enhance early risk stratification in hospitalized patients with COVID-19. Full article

Background: Kidney function is critical for cardiovascular health, and its appropriate assessment entails proper determination of prognosis in patients with chronic coronary syndromes (CCSs). However, assessment of the urinary spot albumin to creatinine ratio (uACR) is often overlooked, whereas it is crucial for determination of chronic kidney disease (CKD). This study assesses the prevalence of impaired kidney function in patients with CCS based on their eGFR and albuminuria. Methods and results: This study comprised a total of 1957 patients from seven regions in Poland, aged ≤ 80 years, who, 6–18 months earlier, were hospitalized for acute coronary syndrome or elective myocardial revascularization. Complete uACR and eGFR data were obtained from 1152 patients (median age was 67 years, and 71.23% of participants were male). The finding of albuminuria reclassified the CKD in 17% (200) patients, suggesting that a patient’s risk cannot be ascertained only based on their eGFR result. CKD reclassification by albuminuria was observed in older (p < 0.001) patients with higher BPs (p = 0.008), BPd (p = 0.038), HR (p < 0.001), fasting glucose (p < 0.001), and HbA1c (p < 0.001) and decreased HDL concentration (p = 0.001); hence, this is the population where uACR assessment is particularly valuable. Conclusions: In a notable percentage of patients with CCS, their kidney function classification is changed based on their albuminuria. Therefore, it is important to include albuminuria in the routine assessment of patients with cardiovascular disease. Full article

IgA nephropathy (IgAN) is the most prevalent primary glomerulonephritis worldwide, with a heterogeneous clinical course that may progress to end-stage kidney disease (ESKD) in approximately 20% of patients. Despite recent advances, including the U.S. Food and Drug Administration (FDA) approval of three novel agents, optimal therapeutic strategies remain uncertain, and access to new drugs is often limited. This underscores the need to evaluate established and widely available options such as mycophenolate mofetil (MMF). The aim of this review is to critically assess the role of MMF, either as monotherapy or in combination with systemic corticosteroids, in the treatment of IgAN based on evidence cited in the KDIGO 2024 Draft Guidelines. We analyzed seven major clinical studies—five randomized controlled trials and two long-term observational studies—with particular focus on the influence of histological activity on treatment outcomes. The Oxford classification was applied to explore whether specific histological variables correlate with prognosis and predict treatment response. Trials conducted in Chinese cohorts demonstrated significant benefits of MMF, including proteinuria reduction, delayed progression to ESKD, and improved long-term renal outcomes, particularly in patients with recent disease onset and active proliferative lesions such as endocapillary hypercellularity and crescent formation. In contrast, studies from Western populations generally failed to demonstrate comparable benefit possibly due to differences in disease chronicity, histopathological patterns, and genetic background. Overall, MMF appears most effective when initiated early and in patients with histologic evidence of intraglomerular inflammation. It may represent a viable steroid-sparing option in appropriately selected patients, particularly where access to newly approved agents is restricted. These population- and pathology-based differences highlight the need for individualized treatment decisions and further research to refine the therapeutic role of MMF in IgAN. Full article

Metabolic acidosis is a common complication of chronic kidney disease (CKD). The kidneys play a crucial role in acid–base balance, maintaining pH within the normal range (isohydria) by following mechanisms: bicarbonate reabsorption, ammogenesis, and titratable acidity. The anion gap describes the amount of unmeasured anions and is classically evaluated as the difference between the major cation (sodium) and the sum of the two major anions (chloride and bicarbonate). Metabolic acidosis can be divided into two types: normal anion gap metabolic acidosis and high anion gap metabolic acidosis. A high anion gap level is considered unfavorable in terms of prognosis as it is associated with increased mortality. Treatment of metabolic acidosis in patients with chronic kidney disease, despite available therapeutic options, is a challenge. Supplementation with bicarbonates does not improve prognosis on the one hand, and on the other hand, it may be harmful. The new KDIGO guidelines for 2024 have been significantly modified compared to 2012 after negative results of studies on bicarbonate supplementation. Bicarbonate supplementation is currently recommended only when levels are less than 18 mmol/L. This review provides an overview of the current knowledge on the pathophysiology, classification, and therapeutic options, including dietary recommendations and new pharmacology agents. Full article

Acute kidney injury (AKI) is a serious clinical condition that is linked to markedly higher rates of morbidity and mortality in cirrhosis patients. Its diagnosis is challenging due to overlapping clinical and laboratory features among causes such as hepatorenal syndrome (HRS), acute tubular injury (ATI), and prerenal hypovolemia. In order to address the distinct pathophysiology and clinical context of cirrhosis, the definitions and classification of AKI have changed over time, moving from RIFLE and AKIN to KDIGO and ICA-AKI. Because cirrhosis patients have altered muscle mass and fluid retention, traditional markers like serum creatinine (sCr) and urine output have significant limitations. Neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), interleukin-18 (IL-18), and cystatin C (CysC) are some of the new biomarkers that have shown promise in early AKI detection and in differentiating structural from functional kidney injury. NGAL and KIM-1 are sensitive indicators of tubular damage with potential prognostic implications. IL-18 reflects inflammatory injury, and CysC offers a more reliable measure of glomerular filtration. Incorporating these markers may improve early diagnosis, risk stratification, and treatment decisions, representing a key direction for future research in managing AKI in cirrhosis. Full article

Background: Heart failure (HF), chronic kidney disease (CKD), and atrial fibrillation (AF) frequently coexist, forming a high-risk triad that amplifies morbidity and mortality through shared pathophysiological mechanisms such as neurohormonal activation, fluid overload, and inflammation. Current risk stratification tools, including CHA₂DS₂-VASc and HAS-BLED, inadequately capture the complexity of these multimorbid patients. This study aims to explore the influence of comorbidities, hypertension severity, anticoagulation strategy, and risk scores on hospitalization outcomes in patients with coexisting HF, CKD, and AF. Materials and Methods: A retrospective case study was conducted on 174 hospitalized patients with HF, CKD, and AF. Clinical data included hypertension grade, HF phenotype (HFpEF vs. HFrEF), NYHA classification, renal function (KDIGO stage), stroke and bleeding risk scores (CHA₂DS₂-VASc: congestive heart failure, hypertension, age ≥ 75, diabetes, and stroke/TIA; HAS-BLED: hypertension, abnormal renal/liver function, stroke, bleeding, labile INR, elderly, and drugs/alcohol), comorbidities (neurological, psychiatric, COPD, and diabetes), anticoagulation type (DOACs vs. VKAs), and length of hospital stay. Statistical analysis included Spearman correlation, independent t-tests, and multivariate regression to evaluate associations between variables and clinical outcomes. Results: Most patients were elderly (mean age 75 ± 12), with advanced CKD (stage 3b) and systolic HF (77% HFrEF). Mean CHA₂DS₂-VASc was 5.67, HAS-BLED was 4.40, and ATRIA was 4.74, indicating high stroke and bleeding risk. Anticoagulation was predominantly via DOACs (69.5%). Hypertension severity did not significantly correlate with NYHA class (ρ = −0.14, p = 0.068). Neurological, psychiatric, and metabolic comorbidities showed no significant associations with HF severity. COPD and diabetes correlated inversely with CHA₂DS₂-VASc scores (ρ = −0.83, p = 0.014). No significant differences were observed in hospital stay between HF phenotypes or prior stroke history. In-hospital mortality was low (2.3%). Conclusions: Traditional risk scores do not fully capture the complexity of multimorbid patients. Metabolic comorbidities showed an inverse correlation with stroke risk scores, and no significant correlation was observed between hypertension severity and HF symptom burden. Hypertension and common comorbidities did not correlate with HF symptom burden, and metabolic diseases may paradoxically associate with lower stroke risk scores. These findings highlight the need for improved multimodal risk assessment strategies that consider the heterogeneity of multimorbid populations. Personalized, integrated approaches are essential to optimize anticoagulation, reduce hospitalization, and improve prognosis. Full article

Background: Differences in serum creatinine (SCr) between the Jaffe and enzymatic methods affect the detection and staging of chronic kidney disease in kidney transplant recipients (KTRs). However, there are very limited data on the extent to which the detection of acute kidney injury (AKI) is affected, what impact immunosuppression can have and whether a KTR-specific estimated glomerular filtration rate (eGFR) formula is beneficial. Methods: A total of 12,081 parallel Jaffe/enzymatic SCr (eSCr) measurements of adult outpatient KTRs (61% male, median age 53 years) in the same serum sample at the University Hospital Essen (Germany) between January 2020 and October 2023 were evaluated. AKI and CKD were defined according to current KDIGO guidelines. The GFR was estimated using CKD-EPI and KTR-specific formulas. Results: In about 1% of all measurements and 5% of the KTR patients, the SCr difference between the two methods was ≥ 0.3 mg/dl. A total of 81% of these patients were male; the median age was 52 years. High levels of immunosuppression, including when Belatacept was used, did not seem to have a clinically relevant impact on the difference between Jaffe and eSCr. The KTR-specific eGFR formula generally showed a greater agreement between Jaffe and eSCr than the CKD-EPI eGFR formula, but they showed differences in the classification of CKD stages, especially in less severe stages. Conclusions: Clinically relevant SCr differences between Jaffe and SCr are rare and depend on the type of immunosuppression. A KTR-specific eGFR formula could be beneficial in some cases, but there are limitations in less severe CKD stages. Full article

Introduction: Acute kidney injury (AKI) among the pediatric population is considered a risk factor for mortality and morbidities during pediatric intensive care unit (PICU) admission. The association between AKI and increased mortality risk and length of stay (LOS) is still inconclusive. This retrospective cohort study aimed to evaluate the impact of AKI severity upon critical management and clinical parameters with an evaluation of severity progression among AKI patients admitted to the PICU at a tertiary care hospital. Methods: AKI, defined with the Kidney Disease Improving Global Outcomes (KDIGO) classification, was determined based on serum creatinine and urine output with respect to the patient’s baseline value. The following outcomes were examined: mortality, mechanical ventilation use, use of non-invasive ventilation, recovery at discharge, and LOS in the hospital and PICU stratified by type of AKI upon admission. Medical records of the 165 included patients were reviewed for clinical data and study outcomes. Results: The median age of the patients was 7 years (IQR 1.5–10 years), and 58% were boys; 78 (47.2%) had stage 1 AKI, 49 (29.71%) had stage 2 AKI, and 38 (23%) had stage 3 AKI at admission. The mortality rate was 26%. The median LOS in the PICU was statistically significant between AKI stages, with a higher median LOS among patients with AKI stage 3 at admission. Using the maximum KDIGO stage, there was no association between AKI and mortality (adjusted OR 1.91, 95% CI 0.05), whereas for the mechanical ventilation outcome, the adjusted OR was 1.84 (95% CI 0.42–8.1). Conclusions: The severity of AKI is not associated solely with mortality and clinical outcomes as the numbers of comorbidities and organ failures contribute to mortality. However, improving awareness of AKI and understanding the disease progression course would reduce acute and long-term morbidity and mortality. Full article

Objective: The present study investigates the incidence of postoperative acute kidney injury (AKI) and related risk factors in patients undergoing total joint arthroplasty. Methods: Included in the study were patients undergoing joint arthroplasty in 2015–2020. The patients with acute or chronic renal failure were excluded. The participants’ demographical data, American Society of Anesthesiologist (ASA) score, Charlson Comorbidity Index (CCI), type of operation, duration of surgery, presence of comorbidities, preoperative anemia, preoperative albumin levels, use of nephrotoxic agents, number of transfusions during perioperative period, presence of AKI according to Kidney Disease Improving Global Outcome (KDIGO) scores, and length of hospital and intensive care unit stay were evaluated. Results: The study was initiated with 1780 patients: 113 patients were excluded due to chronic kidney failure, 108 patients were excluded due to acute kidney failure, 648 patients were excluded because their data could not be reached, and finally, 911 patients were included in the study. AKI was detected in 134 patients (14.7%), and the number of patients in the KDIGO1 and KDIGO2 groups were 120 and 14, respectively. When evaluated according to the variable significance test result and clinical significance, the model consists of variables such as ASA, CCI, hypertension, nonsteroidal anti-inflammatory drugs (NSAIDs), vancomycin, beta lactam, contrast material and preoperative anemia, operation type, and anesthesia management. Machine learning analyses were performed using 11 variables (10 independent and 1 dependent variable). Logistic regression, naive Bayes, multilayer perceptron, bagging, and random forrest approaches were used for evaluation of the predictive performance. In an evaluation of the true classification ratio, the best result was obtained with the logistic regression method at 85.2%. Conclusions: The study revealed advanced age, high ASA and CCI, presence of diabetes and hypertension, NSAID, vancomycin and contrast material, and the presence of preoperative anemia to be independent risk factors for AKI. Full article

Background: Acute kidney injury (AKI), a prevalent postoperative complication, predominantly manifests as stage 1, characterized by a mild elevation in serum creatinine (SCr). There is yet to be a consensus regarding the association between stage 1 AKI and adverse outcomes in surgical patients. Methods: This retrospective study enrolled adult patients who underwent at least one surgery during hospitalization from the MIMIC IV database. AKI was diagnosed when the KDIGO creatinine criteria were satisfied within 7 days after surgery. Stage 1a AKI was defined as an absolute increase in SCr of 26.5 μmol/L, and stage 1b was defined as a 50% relative increase. Stage 1 AKI was also divided into transient and persistent substages based on whether the AKI recovered within 48 h after onset. The association between stage 1 AKI and its substages and in-hospital mortality was evaluated. Results: Among 49,928 patients enrolled, 9755 (19.5%) developed AKI within 7 days after surgery, of which 7659 (78.5%) presented with stage 1 AKI. The median follow-up was 369 (367, 372) days. Stage 1 AKI was significantly associated with in-hospital mortality after adjustment (aHR, 2.73; 95% CI, 2.29, 3.26). Subgroup analyses showed that the risk of stage 1 AKI on in-hospital mortality was attenuated by age ≥ 65 years (p for interaction = 0.017) or a baseline eGFR < 60 mL/min per 1.73 m² (p for interaction = 0.001). Compared with non-AKI, patients with stage 1b (aHR, 3.06; 95% CI, 2.56, 3.66) and persistent stage 1 (aHR, 2.03; 95% CI, 1.61, 2.57) AKI had an increased risk of in-hospital mortality; however, this risk was not significant in those with stage 1a (aHR, 1.01; 95% CI, 0.68, 1.51) and transient stage 1 (aHR, 1.11; 95% CI, 0.79, 1.57) AKI. Conclusions: Stage 1 AKI exhibits an independent correlation with a heightened mortality risk among surgical patients. Consequently, a tailored adaptation of the KDIGO AKI classification may be necessitated for the surgical population, particularly those presenting with decreased baseline kidney function. Full article

Introduction: COVID-19, caused by the SARS-CoV-2 virus, has been associated with oligosymptomatic cases or severe acute respiratory syndrome, with multiple organ failure and death. One of the most significant events for clinical outcomes is Acute Kidney Injury (AKI). It is known that AKI in COVID-19 is multifactorial, and the main mechanisms are cytokine storm, metabolic stress, use of nephrotoxic drugs, rhabdomyolysis, viral tropism to kidney tissues, and multiple organ failure. However, little is known about the impact of AKI clinical presentation and pathophysiological mechanisms on the outcome of patients affected by COVID-19. Objectives: To identify AKI clinical presentation and etiology, also known as phenotypes, and pathophysiological mechanisms, also known as subphenotypes, in patients affected by COVID-19 and associate them with death. This cohort and retrospective study evaluate the medical records of patients with SARS-CoV-2 infection admitted to a tertiary public hospital from 1 June 2020, to 31 July 2021, from admission to clinical outcome (hospital discharge or death). Clinical and laboratory data were analyzed during the hospitalization. Renal function was estimated by urine output and serum creatinine; therefore, the diagnosis and AKI classification were based on the 2012 KDIGO criteria. The occurrence of AKI was the inclusion criterion. According to clinical and laboratory presentations, we recognized two phenotypes of AKI (the direct and indirect impact of SARS-CoV-2 on the kidney) and several pathophysiological mechanisms. Subphenotypes of the direct impact of SARS-CoV-2 on kidneys were associated with Kidney Viral Tropism, Cytokine Storm, COVID-19-Related Multiple Organ Failure, and Mixed (more than one mechanism associated with COVID-19). Subphenotypes of indirect impact of SARS-CoV-2 on kidney phenotypes were Ischemic, Nephrotoxic due to rhabdomyolysis, and Septic. Univariate and multivariate analyses were performed to identify risk factors associated with death. Result: In total, 372 patients were included; 55.6% were male, 82.3% were Caucasians, and the mean age was 61.4 years. The majority of patients were admitted to the ICU (88.2%) and required mechanical ventilation (86.3%). AKI was predominantly KDIGO 3 (65.6%). When classifying our patients’ AKI in two kidney phenotypes based on their clinical presentation, the direct impact of the SARS-CoV-2 phenotype was predominant (71,5%) and associated with higher mortality (83.8 vs. 46.3%, p = 0.001). Among the AKI pathophysiological mechanisms, Mixed—synergism of viral mechanisms—was the most prevalent (23.4%), followed by Viral Tropism (19.9%), Multiple Organ Failure—MOF (18%), Septic (15.6%), Ischemic (12.9%), and Cytokine Storm (10.2%). Mortality was high (73.1%). Logistic regression identified APACHE II, ATN-ISS, and the direct impact of SARS-CoV-2 on the kidney as factors associated with death, while ischemic AKI was associated with lower mortality. Conclusions: We can conclude that APACHE II and ATN-ISS scoring are clinical predictions of hospital mortality in COVID patients with AKI, as well as AKI etiology involving the direct impact of SARS-CoV-2 on the kidney, while ischemic pathophysiological mechanisms of AKI are associated with lower mortality. Full article