Background: Since the start of the coronavirus disease 2019 (COVID-19) pandemic, millions have succumbed to the infection worldwide. The virus is most well-known for its devastating pulmonary and cardiovascular manifestations, but acute kidney injury (AKI) has been frequent as well (reported incidence ranging from 0.5% to 56.9%), and has been repeatedly observed to be associated with increased mortality. The cause of renal injury is not clearly understood and thought to be a cumulative effect of hemodynamic instability, underlying comorbidities, medication exposure, and direct viral injury. We aimed to calculate the incidence of AKI among patients with COVID-19, to discern predisposing comorbid conditions, and to describe time to recovery when present and the therapeutic interventions used.

Methods: This was a retrospective cohort study of patients admitted to Lyndon B. Johnson Hospital between March 29, 2020 and January 29, 2021 who tested positive for COVID-19. Data was collected from the electronic medical record regarding demographic information, comorbid conditions, and a variety of exposures including the presence of sepsis. Laboratory results, including baseline and peak creatinine, highest BUN, and electrolytes, were collected. These data points were compared between patients who developed AKI and those who did not.

Results: Results:Among the 615 patients who were considered for analysis, 51% were male with a median age of 52 years. Obesity (56%), hypertension (48%), and diabetes mellitus (46%) were the most frequently present comorbid conditions. AKI occurred in 22% of the cohort; those who developed AKI were more likely to suffer from diabetes, hypertension, and heart failure. AKI was notably more frequently among patients who presented with sepsis (P <0.0001). Exposures to intravenous contrast, beta lactam antimicrobials, intravenous heparin, ACE inhibitors/ARBs, and remdesivir were more common among patients who suffered AKI. Using a logistic regression model, hypertension (OR 1.80, 95% CI 1.14 to 2.82, P=0.01) and sepsis (OR 9.46, 95% CI 5.79 to 15.46, P<0.0001) were the variables that most strongly predicted AKI development. Among those with AKI, 52 patients (38%) required hemodialysis. Overall mortality was 10%, with death occurring significantly more often in the AKI cohort (38% vs. 2%, P < 0.0001). Recovery of renal function, defined as a return to baseline creatinine ± 20%, occurred in an average of 9 days with an extremely broad range (1 to 240 days).

Conclusions: AKI is a common occurrence among patients with COVID-19 infection and is associated with increased mortality. Those with comorbid illnesses, particularly those known to affect renal function, were more likely to develop AKI. Patients who presented with sepsis were also more frequently found to have AKI. More research needs to be conducted to understand the mechanisms of AKI in patients with COVID-19 and what can be done to prevent or mitigate renal injury.

IMAGE 1: Table 1. Baseline characteristics of patients with COVID-2019 and at least two values of serum creatinine (n=615 patients)

IMAGE 2: Table 2. Comparison of patients with COVID-19 with and without AKI. References: (*): peripheral or coronary atherosclerosis; (@): angiotensin II receptor blocker; (#): proton pump inhibitor; ($): non-steroidal anti-inflammatory