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Kidney Week

Abstract: FR-PO066

The Burden of AKI in a Cohort of 5217 CKD Patients

Session Information

Category: Acute Kidney Injury

  • 101 AKI: Epidemiology‚ Risk Factors‚ and Prevention

Authors

  • Schultheiss, Ulla T., Institute of Genetic Epidemiology, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany
  • Kotsis, Fruzsina Kinga, Institute of Genetic Epidemiology, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany
  • Behning, Charlotte, Institute of Medical Biometry, Informatics and Epidemiology, University Hospital Bonn, Bonn, Germany
  • Nadal, Jennifer, Institute of Medical Biometry, Informatics and Epidemiology, University Hospital Bonn, Bonn, Germany
  • Kottgen, Anna, Institute of Genetic Epidemiology, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany
  • Eckardt, Kai-Uwe, Department of Nephrology and Medical Intensive Care, Charité – Universitätsmedizin Berlin, Berlin, Germany
  • Schneider, Markus P., Department of Nephrology and Hypertension, Friedrich-Alexander- University Erlangen-Nürnberg, Erlangen-Nürnberg, Germany
Background

Chronic Kidney Disease (CKD) is associated with an increased risk for acute kidney injury (AKI), which is a risk factor for mortality. While in-patient AKI has been studied extensively, characteristics of out-patient AKI have been less studied. We therefore characterized in- and out-patient AKI in a large German CKD (GCKD) patient cohort.

Methods

Over 6.5 years of follow-up, in-patient-AKI events were adjudicated from hospital discharge letters and categorized based on the GCKD study adjudication catalogue: i) increase of creatinine >0.3 mg/dl, ii) doubling to triplication of creatinine, iii) creatinine value >4 mg/dl plus an acute increase of >0.5 mg/dl, iv) initiation of temporary renal replacement therapy. Out-patient-AKI events were calculated based on an algorithm by Hapca et al. 2020, using time windows prior- and post-AKI, applying similar criteria to categorize AKI as for in-patient-AKI.

Results

In 5217 CKD patients, 1411 in-patient-AKI events in 636 participants (median 1, IQR: 1-6) vs. 1114 out-patient-AKI events in 624 participants (median 1, IQR: 1-10) occurred. Recurrent events were recorded more frequently for out-patient-AKI compared to in-patient-AKI. Baseline characteristics for participants without any AKI event compared to participants experiencing at least one event in either in-patient-AKI or out-patient-AKI were a mean ± standard deviation (m ± sd) age for participants without an AKI event of 59.3 ±12.2 years, of 62.2 ±10.7 for in-patient-AKI, and of 58.8 ±12.6 for out-patient-AKI. Men were more likely to experience an AKI event than women for both in- and out-patient-AKI. Mean baseline eGFR values were lowest for participants without AKI (29.5 ±5.8 ml/min/1.73m2), but similar for both in-patient and out-patient-AKI (~31.1 ± 6.3 ml/min/1.73m2). Median UACR values were >300 mg/g for those with an out-patient-AKI event compared to 52.7 mg/g for those with an in-patient-AKI event. Prevalent cardiovascular disease was similar between in-patient-AKI and out-patient-AKI groups (e.g. 30% coronary heart disease), but ~8-15% higher than for participants without AKI.

Conclusion

Our study emphasizes the high burden of both in- and out-patient-AKI in CKD patients. Our analysis could further demonstrate that UACR values were higher for out-AKI-patients, which may help to better target preventative measures.