Urinary sodium excretion is low prior to acute kidney injury in patients in the intensive care unit

Low urinary sodium-to-potassium ratio in the early phase following single-unit cord blood transplantation is a predictive factor for poor non-relapse mortality in adults

Although daily higher urinary sodium (Na) and potassium (K) excretion ratio is associated with the risk of cardiovascular disease in the general population, a low Na/K ratio is associated with renal dysfunction in critically ill patients. Thus, we retrospectively analyzed the impact of daily urinary Na and K excretion and their ratio on non-relapse mortality (NRM) and overall mortality in 172 adult single-unit cord blood transplantation (CBT) patients treated at our institution between 2007 and 2020. Multivariate analysis showed that a low urinary Na/K ratio at both 14 days (hazard ratio [HR], 4.82; 95% confidence interval [CI], 1.81-12.83; P = 0.001) and 28 days (HR, 4.47; 95% CI 1.32-15.12; P = 0.015) was significantly associated with higher NRM. Furthermore, a low urinary Na/K ratio at 28 days was significantly associated with higher overall mortality (HR, 2.38; 95% CI 1.15-4.91; P = 0.018). Patients with a low urinary Na/K ratio had decreased urine volume, more weight gain, experienced more grade III-IV acute graft-versus-host disease, and required corticosteroids by 28 days after CBT. These findings indicate that a low urinary Na/K ratio early after single-unit CBT is associated with poor NRM and survival in adults.

Precision management of acute kidney injury in the intensive care unit: current state of the art

Acute kidney injury (AKI) is a prototypical example of a common syndrome in critical illness defined by consensus. The consensus definition for AKI, traditionally defined using only serum creatinine and urine output, was needed to standardize the description for epidemiology and to harmonize eligibility for clinical trials. However, AKI is not a simple disease, but rather a complex and multi-factorial syndrome characterized by a wide spectrum of pathobiology. AKI is now recognized to be comprised of numerous sub-phenotypes that can be discriminated through shared features such as etiology, prognosis, or common pathobiological mechanisms of injury and damage. The characterization of sub-phenotypes can serve to enable prognostic enrichment (i.e., identify subsets of patients more likely to share an outcome of interest) and predictive enrichment (identify subsets of patients more likely to respond favorably to a given therapy). Existing and emerging biomarkers will aid in discriminating sub-phenotypes of AKI, facilitate expansion of diagnostic criteria, and be leveraged to realize personalized approaches to management, particularly for recognizing treatment-responsive mechanisms (i.e., endotypes) and targets for intervention (i.e., treatable traits). Specific biomarkers (e.g., serum renin; olfactomedin 4 (OLFM4); interleukin (IL)-9) may further enable identification of pathobiological mechanisms to serve as treatment targets. However, even non-specific biomarkers of kidney injury (e.g., neutrophil gelatinase-associated lipocalin, NGAL; [tissue inhibitor of metalloproteinases 2, TIMP2]·[insulin like growth factor binding protein 7, IGFBP7]; kidney injury molecule 1, KIM-1) can direct greater precision management for specific sub-phenotypes of AKI. This review will summarize these evolving concepts and recent innovations in precision medicine approaches to the syndrome of AKI in critical illness, along with providing examples of how they can be leveraged to guide patient care.