Response to the Letter to the Editor Concerning the Article on COVID-19–Associated Acute Kidney Injury

Abstract

We would like to thank the reader for their critical appraisal and comments regarding our article, “Factors Associated with Acute Kidney Injury Due to COVID-19 and Its Relationship with the Need for Renal Replacement Therapy in the Intensive Care Unit of a Peruvian Hospital”. These observations provide an opportunity to clarify key concepts in a complex clinical setting such as the intensive care unit (ICU), where acute kidney injury (AKI) is often multifactorial and is associated with disease severity, the systemic inflammatory response, hemodynamic support, and mechanical ventilation, in addition to SARS-CoV-2 infection.

First, regarding the causal attribution expressed as “AKI due to COVID-19,” we acknowledge that this terminology may be interpreted as implying a single causal mechanism. In our manuscript, our intention was to describe AKI occurring in critically ill patients with confirmed COVID-19, within a framework of temporal and clinical association. Consistent with the literature, AKI in COVID-19 involves both direct and indirect mechanisms, including systemic inflammation, endothelial dysfunction, microthrombosis, hypoxemia, and hemodynamic instability. Therefore, we consider it appropriate to use more precise terminology, such as “AKI in patients with COVID-19” or “COVID-19-associated AKI,” which avoids implying exclusive etiological attribution, as suggested by other authors.

Second, we agree on the importance of reporting standardized diagnostic and staging criteria. The internationally accepted definition of AKI is based on changes in serum creatinine levels or urine output, as established by the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines. Given the retrospective nature of our study and the heterogeneous availability of medical record data, our study relied on the information documented by the treating team and on the available clinical data. Therefore, in future versions and related studies, we will provide a more detailed description of the operational definition of AKI and the clinical assessment of prerenal, intrinsic renal, and postrenal etiologies, as well as the presence of pre-existing chronic kidney disease, in order to strengthen reproducibility and clinical interpretation.