Acute kidney injury and its progression in hospitalized patients-Results from a retrospective multicentre cohort study with a digital decision support system

Acute Kidney Injury Induces Oxidative Stress and Hepatic Lipid Accumulation through AMPK Signaling Pathway

Acute kidney injury (AKI) often impairs the function of other organs leading to distant organ injury. The liver is the major organ that regulates metabolism and lipid homeostasis in the body. It has been reported that AKI causes liver injury with increased oxidative stress, inflammatory response and steatosis. In the present study, we investigated the mechanisms by which ischemia-reperfusion-induced AKI caused hepatic lipid accumulation. Kidney ischemia (45 min)-reperfusion (24 h) led to a significant increase in plasma creatinine and transaminase in Sprague Dawley rats, indicating kidney and liver injury. Histological and biochemical analyses revealed hepatic lipid accumulation with a significant elevation of triglyceride and cholesterol levels in the liver. This was accompanied by a decreased AMP-activated protein kinase (AMPK) phosphorylation, indicating the reduced activation of AMPK, which is an energy sensor that regulates lipid metabolism. The expression of AMPK-regulated genes that were responsible for fatty acid oxidation (CPTIα, ACOX) was significantly decreased, while the expression of lipogenesis genes (SREPB-1c, ACC1) was significantly elevated. The oxidative stress biomarker malondialdehyde was elevated in the plasma and liver. Incubation of HepG2 cells with an oxidative stress inducer hydrogen peroxide inhibited AMPK phosphorylation and caused cellular lipid accumulation. This was accompanied by decreased expression of genes responsible for fatty acid oxidation and increased expression of genes responsible for lipogenesis. These results suggest that AKI elicits hepatic lipid accumulation through decreased fatty acid metabolism and increased lipogenesis. Oxidative stress may contribute, in part, to the downregulation of the AMPK signaling pathway leading to hepatic lipid accumulation and injury.

Laboratory Diagnostic of Acute Kidney Injury and Its Progression: Risk of Underdiagnosis in Female and Elderly Patients

Acute kidney injury (AKI) is a common disease, with high morbidity and mortality rates. In this study, we investigated the potential influence of sex and age on laboratory diagnostics and outcomes. It is known that serum creatinine (SCr) has limitations as a laboratory diagnostic parameter for AKI due to its dependence on muscle mass, which may lead to an incorrect or delayed diagnosis for certain patient groups, such as women and the elderly. Overall, 7592 cases with AKI, hospitalized at the University of Leipzig Medical Center (ULMC) between 1st January 2017 and 31st December 2019, were retrospectively analyzed. The diagnosis and staging of AKI were performed according to the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines, based on the level and dynamics of SCr. The impact of sex and age was analyzed by the recalculation of a female to male and an old to young SCr using the CKD-EPI equation. In our study cohort progressive AKI occurred in 19.2% of all cases (n = 1458). Female cases with AKI were underrepresented (40.4%), with a significantly lower first (-3.5 mL/min) and last eGFR (-2.7 mL/min) (p < 0.001). The highest incidence proportion of AKI was found in the [61-81) age group in female (49.5%) and male (52.7%) cases. Females with progressive AKI were underrepresented (p = 0.04). By defining and staging AKI on the basis of relative and absolute changes in the SCr level, it is more difficult for patients with low muscle mass and, thus, a lower baseline SCr to be diagnosed by an absolute SCr increase. AKIN1 and AKIN3 can be diagnosed by a relative or absolute change in SCr. In females, both stages were less frequently detected by an absolute criterion alone (AKIN1 ♀ 20.2%, ♂ 29.5%, p < 0.001; AKIN3 ♀ 13.4%, ♂ 15.2%, p < 0.001). A recalculated SCr for females (as males) and males (as young males) displayed the expected increase in AKI occurrence and severity with age and, in general, in females. Our study illustrates how SCr, as the sole parameter for the diagnosis and staging of AKI, bears the risk of underdiagnosis of patient groups with low muscle mass, such as women and the elderly. A sex- and age-adapted approach might offer advantages.

Incidence of hospital contacts with acute kidney injury after initiation of second-generation antipsychotics in older adults: a Danish population-based cohort study

Purpose

To investigate the association between acute kidney injury (AKI) and use of second-generation antipsychotics (SGA) in older adults.

Methods

In a population-based cohort study using Danish national registries, new users of SGAs (aged ≥ 65) were identified during 2005–2015. Each SGA user was matched to 10 population controls on age, sex, and the SGA initiation date. The outcome was incident AKI within 90 days after the index date. Cox regression was used to estimate hazard ratios (HRs) with 95% confidence intervals (CIs), adjusting for potential confounders.

Results

In the study, 36,581 new SGA users and 365,810 controls were included. The 90-day incidence rate of AKI was 4.38 and 1.70 per 1000 person-years among SGA users and controls, respectively, corresponding to a crude HR of 2.57 (1.79–3.68). The fully adjusted HR (aHR) was 1.43 (0.89–2.27) for all SGAs. The risk differed among individual drugs with aHRs for olanzapine 3.50 (1.20–10.23), quetiapine 1.62 (0.81–3.26), and risperidone 0.68 (0.28–1.64). In sensitivity analyses, the aHR declined to 1.24 (0.95–1.61) at 1-year follow-up.

Conclusions

Olanzapine use was associated with a significantly increased 90-day AKI risk. For quetiapine, the risk was elevated but not significant, and risperidone had no association. CIs were wide and confounder adjustment largely impacted the estimates. Main limitations included residual confounding and incomplete recording of AKI diagnoses.

Supplementary information

The online version contains supplementary material available at 10.1007/s00228-022-03339-6.

[Epidemiology and Causes of Acute Renal Failure and Transition to Chronic Kidney Disease]

Acute kidney injury (AKI) refers to an acute functional deterioration of the kidneys, which leads to retention of urinary substances, dysregulation of the electrolyte and acid-base balance, and disturbance of fluids. Although didactically helpful, the oversimplified AKI classification of prerenal/renal/postrenal is currently considered obsolete. Indeed, the boundaries blur quite quickly, particularly between prerenal and renal causes. Based on the AKI pathophysiology, it can be etiologically divided into decreased renal perfusion, postrenal obstruction and kidney specific injury or unspecific injury. AKI is a common event in hospitalized patients and associates strongly with mortality and chronic kidney disease (CKD). Today it is accepted that AKI and CKD are rather an individually variable continuum, than 2 distinct entities. If AKI has not regressed after 7 days, it is referred to as acute kidney disease (AKD). Persisting AKD for > 90 days is classified as CKD. The transition from AKD to CKD is the result of an incomplete and maladaptive repair process. Although follow-up of post-AKI patients is essential, optimal concepts still need to be developed.

Novelle QLL 2020 – welche Auswirkungen haben die neu empfohlenen Hämoglobin-Transfusionstrigger auf die klinische Versorgung?

In der Gesamtnovelle der Querschnittsleitlinie (QLL) Hämotherapie der Bundesärztekammer (BÄK) 2020 wurde der Hämoglobin-Transfusionstrigger (Hb-Transfusionstrigger) bei akutem Blutverlust ohne zusätzliche Risikofaktoren aufgrund einer Neubewertung der internationalen Evidenz von 3,7 mmol/l (6 g/dl) auf 4,3 mmol/l (7 g/dl) angepasst. Ziel der vorliegenden Studie ist die retrospektive Analyse des Transfusionsverhaltens von EK bezüglich der Maßgaben der QLL. Zu diesem Zweck analysierten wir individuelle Prä- und Posttransfusions-Hb-Werte von Erythrozytenkonzentraten (EK), die im 4. Quartal 2019 (4946 EKs, 129 560 Hb-Werte) und 2020 (5502 EKs, 134 404 Hb-Werte) am Universitätsklinikum Leipzig (UKL) transfundiert wurden. Der mediane Hb-Wert vor der Transfusion betrug 4,3 mmol/l (7 g/dl) (680 medizinische Fälle, die 2724 EK in 1801 Transfusionen im Jahr 2019 erhielten). Von allen Transfusionen im Jahr 2019 zeigten 899 (49,9%) Transfusionen Hb-Werte < 4,3 mmol/l (7 g/dl) vor der Transfusion, während 152 (8,4%) Hb-Werte < 3,7 mmol/l (6 g/dl) aufwiesen. 2020 wurden jeweils vergleichbare Ergebnisse ermittelt. Wir zeigen, dass der mediane Hb-Anstieg nach der Transfusion eines EK 0,6 mmol/l (1 g/dl) betrug. 34,7% aller Transfusionen erreichten den erwarteten Anstieg von 0,6 mmol/l (1 g/dl) pro EK. Der absolute Anstieg nahm bei Transfusionen mit mehreren EK im Vergleich zu Transfusionen mit einem EK nicht linear zu. Der Grad der Hb-Erhöhung korrelierte invers mit dem Hb-Wert vor Transfusion. Der Hb-Wert nach der Transfusion wurde bei 96,3% der Fälle innerhalb von 24 Stunden nach Hämotherapie kontrolliert. Zusammenfassend spiegelt das Transfusionsverhalten generell die Empfehlungen der Leitlinie. Um ein optimiertes, individualisiertes und dennoch restriktives Transfusionsverhalten bei EK zu erreichen, schlagen wir die Implementierung eines klinischen Entscheidungsunterstützungssystems (CDSS) bei Verschreibung jeder einzelnen EK-Transfusion vor, welches Ärzte bei der Einhaltung der Transfusionsleitlinie unterstützt und über Abweichungen informiert.