Published: 9 February 2022| Version 1 | DOI: 10.17632/2kj8jfgndw.1


Background: Since February 2020 COVID-19 infection spread in Italy, violently hitting the Lombardy region. Despite high diffusion, only a subset of patients developed severe COVID-19: around 25% of them developed AKI and one-third of them died. Elderly patients and patients with high comorbidity have been identified as at higher risk of severe COVID-19. Methods: In a prospective observational cohort study 392 consecutive patients hospitalized for COVID-19 in Milan (age 67 years, 75% male) were included. We evaluated the relationship between blood pressure at presentation, presence of AKI at Emergency Room presentation and during hospitalization, and total in-hospital mortality (24%). Results: Despite 58% reported a history of hypertension (86% treated) 30% of patients presented with low blood pressure levels. Only 5.5% were diagnosed with AKI on admission; 75% of hypertensive patients discontinued therapy during hospitalization (only 20% were treated at discharge). Gender and hypertension were strongly associated with AKI at admission time (odds ratio 11). Blood pressure was inversely correlated with increased risk of AKI upon admission, independently of the severity of respiratory distress. Age over 65, history of hypertension, and severity of respiratory distress were the main predictors of AKI during hospitalization (developed in 34.7% of the cases). AKI was associated with increased in-hospital mortality. Hypertension and low levels of blood pressure at presentation were the main predictors of in-hospital mortality, together with age over 65, baseline pulmonary involvement, and severity of illness. Conclusions: In patients hospitalized for COVID-19, hypertension and low levels of blood pressure at presentation are important risk factors for AKI and mortality. Early reduction of antihypertensive therapy may improve outcomes in SARS-CoV-2 infection. doi: 10.17632/2kj8jfgndw.1


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The main outcomes were the presence of AKI at admission in Emergency Department, AKI development during hospitalization and in-hospital death. Follow-up time was right-censored on April 25, 2020. Baseline serum creatinine was defined as the most recent available creatinine value in the previous six months in a stable clinical condition if available (21%) or the last value available previous discharge. The minimum creatinine value available during hospitalization was selected as the baseline renal function for those patients who died during the study. Estimated glomerular filtration rate (eGFR) was calculated with the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation . We considered two different forms of AKI: the presence of AKI on the day of Emergency Department admission and the AKI development during hospitalization. AKI was defined as a 50% increase in serum creatinine from baseline according to the KDIGO criteria. For cases with AKI at the presentation we compared basal value with the first creatinine value available after Emergency Department admission; AKI during hospitalization was defined as the earliest serum creatinine change during hospitalization meeting KDIGO criteria and the day of in-hospital AKI was the relative one. SpO2/FiO2 was used as an indicator of the severity of respiratory distress; it was recoded in 4 classes defined as by SOFA score. Statistical methods For mortality analysis, we created Kaplan-Meier cumulative incidence plots. We estimated hazard ratio (HR) for death using the Cox proportional hazards model; time-to-event was expressed in days from the date of hospital admission to the date of in-hospital death. To investigate the relationship between SARS-CoV-2 infection, blood pressure dysregulation, kidney damage and mortality rate, a multivariable Cox regression model with eleven variables was performed. To identify risk factors associated with the development of AKI (both AKI at presentation in Emergency Department and AKI during hospitalization), we performed a logistic regression model, using stepwise procedure, with odds ratio (OR) estimation. All analyses were done using SPSS (version 24; IBM corporation)


Ospedale San Raffaele


Hypertension, Acute Kidney Injury, Chronic Kidney Disease, COVID-19