Urine Sediment Analysis Independent Predictor of Mortality in AKI Patients with Severe COVID-19: Study

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) frequently triggers acute kidney injury, a primary driver of morbidity. Although traditional urinary biochemistry distinguishes renal lesions, its prognostic utility remains a major clinical gap, leading Froylan David Martínez-Sánchez and colleagues at Hospital General Dr. Manuel Gea Gonzalez to evaluate if urinary indices and microscopy can effectively predict AKI progression and 28-day mortality.

Therefore, the retrospective cohort study tracked 217 adults with severe COVID-19 and stage 1 AKI at a Mexican tertiary center over 20 months, assessing 28-day mortality and renal progression via systematic renal tubular epithelial cell and granular cast analysis. Utilizing Cox regression and excluding incomplete datasets, the methodology ensured clinically robust findings on the Perazella score’s ability to predict patient decline.

Key Clinical Findings of the Study Include:

• Predictive Sediment Value: The study credits a stage 3 Perazella score with a significant hazard ratio of 2.630 for advancement to more severe kidney injury stages.

• Enhanced Mortality Risk: According to the study, Perazella scores of 2 and 3 were independently linked to increased mortality, yielding hazard ratios of 3.465 and 2.857, respectively.

• Biochemical Marker Limitations: The research credits traditional urinary indices, such as fractional excretion of sodium (FeNa) and blood urea nitrogen to creatinine (BUN/Cr) ratios, with no significant statistical association regarding clinical worsening or patient survival.

• Progression Dynamics: The study credits the observed patient population with a 32.7% progression rate from initial stage 1 AKI to advanced stages, with 18.9% specifically reaching stage 3.

• Systemic Inflammation Impact: The investigation credits non-surviving patients with significantly higher levels of inflammatory markers like D-dimer and ferritin compared to survivors, highlighting the systemic nature of the illness.

The results suggest that while urinary indices are not useful for predicting outcomes, urine microscopy serves as a powerful indicator of tubular damage, as 32.7% of patients experienced renal progression and the overall 28-day mortality reached 27.2% among the cohort.

Thus, the study concludes that clinicians might consider incorporating routine urine sediment examination into standard care protocols for severe COVID-19 to facilitate the early identification of patients at high risk for deteriorating renal function.

Although the single-center retrospective design and absence of biopsy data are noted limitations, these results highlight the potential for future multicenter trials to further validate the prognostic utility of urine microscopy in managing complex renal injuries.

Reference

Martínez-Sánchez FD, Vasquez-Vasquez JA, Vargas-Sánchez LV, Díaz-Echevarría AF, Flores Perez FI, Moreno-Novales R, et al. Association of Urinary Indices and Urine Microscopy with the Progression of Acute Kidney Injury and Mortality in Hospitalized Patients with Severe COVID-19. Indian J Nephrol. 2026;36:221-6.