The inflammatory component of diabetic kidney disease has become of great interest in recent years, with genetic and epigenetic variants playing a fundamental role in the initiation and progression of the disease. Cells of the innate immune system play a major role in the pathogenesis of diabetic kidney disease, with a lesser contribution from the adaptive immune cells. Other components such as the complement system also play a role, as well as specific cytokines and chemokines. The inflammatory component of diabetic kidney disease is of great interest and is an active research field, with the hope to find potential innovative therapeutic targets.

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<b><i>Background:</i></b> Acute kidney injury (AKI) is a well-recognized complication of coronavirus disease 2019 (COVID-19). The short and long-term outcomes of patients who develop AKI have not been well characterized. <b><i>Methods:</i></b> In this multicenter retrospective cohort study, we describe the clinical characteristics and outcomes of critically ill adults with severe COVID-19 and AKI. Patient-level variables were extracted from the electronic medical record. Using nadir-to-peak serum creatinine, AKI was defined using the KDIGO definition. Multivariable logistic regression analyses examined factors associated with development of moderate-to-severe (stage 2–3) AKI, severe (stage-3) AKI, and the composite of renal replacement therapy (RRT) or in-hospital death. <b><i>Results:</i></b> Among 459 critically ill adults with COVID-19, 371 (80.1%) developed AKI, with 179 (37.9%) developing stage-3 AKI. Male gender, black and Asian/Native American race, lower baseline estimated glomerular filtration rate (eGFR), higher body mass index (BMI), and higher Acute Physiology and Chronic Health Evaluation (APACHE) IV score were more prevalent among patients with severe AKI, as were systemic markers of inflammation. On multivariable analysis, male gender, black and Asian/Native American race, higher APACHE IV score, lower baseline eGFR, and higher BMI (mainly the highest BMI stratum ≥35 kg/m²) were independently associated with higher stages of AKI severity. Male gender, lower baseline eGFR, and higher APACHE IV score were also independently associated with the composite of RRT or in-hospital death. Moderate-to-severe AKI and severe AKI were independently associated with in-hospital death, and there was a significant interaction between BMI and moderate-to-severe AKI for the outcome of in-hospital death. Among 83 (18.1%) patients who required RRT, 27 (32.5%) survived, and 12 (44.4%) remained dialysis-dependent at discharge. At 3 and 6 months, 5 (41.7%) and 4 (33.3%) remained dialysis-dependent, respectively. <b><i>Conclusions:</i></b> AKI is common in critically ill adults with COVID-19. Several patient-level risk factors are associated with higher stages of AKI severity. BMI might be an effect modifier of AKI severity for in-hospital death. Among AKI survivors, there is a high rate of short- and long-term dialysis dependence.