Prognostic Significance of Acute Kidney Injury and Proteinuria for Mortality in COVID-19: Insights from a Single-center Cohort

Introduction: COVID-19, first identified in China in 2019, caused significant global morbidity and mortality. Acute kidney injury (AKI) and proteinuria are common complications in hospitalized patients and may serve as critical predictors of mortality. This study aimed to assess the prognostic significance of kidney-related complications in hospitalized COVID-19 patients at Sayyad Shirazi Hospital, Shiraz, Iran, from March 2021 to March 2022. Methods: In this descriptive cross-sectional study, 99 hospitalized COVID-19 patients with AKI were included. Demographic data, clinical symptoms, renal complications, underlying conditions, and mortality rates were recorded. Associations between AKI, proteinuria, comorbidities, and inhospital mortality were analyzed using descriptive statistics and chi-square/Fisher’s exact tests. Results: The cohort included 45% female and 55% male patients, with a mean age of 50.15 ± 34.48 years. Overall, 26% of patients died, 83% had underlying conditions, and 61% exhibited proteinuria. Pre-discharge creatinine levels were on average 6.11 units higher than baseline, decreasing by 1.11 units post-discharge. Mortality was significantly higher among patients with AKI, proteinuria, and comorbidities, with deceased patients showing markedly elevated pre-discharge creatinine levels. Conclusions: AKI and proteinuria are strong predictors of mortality in hospitalized COVID-19 patients. Early recognition and monitoring of renal involvement, alongside assessment of comorbidities, can guide risk stratification and inform timely interventions. This study contributes to the existing literature by highlighting the prognostic value of renal markers in COVID-19 and underscores the need for proactive renal management to improve patient outcomes.