The COVID-19 pandemic and kidney involvement constitute an evolving story with various twists and turns, and we expect new challenges as we enter the third year of the pandemic. In spring and summer of 2020, COVID-19-associated acute kidney injury (AKI) was one of the biggest challenges in hospitals, as physicians and staff dealt with a surge of COVID-19 patients on the wards and in the intensive care units (ICUs). The incidence of COVID-19-associated AKI in ICUs ranged from 61% to 76% in the United States, with approximately 30% of ICU patients needing kidney replacement therapy (KRT) (1). Patients with COVID-19 and AKI have a very high morbidity and mortality (2) and COVID-19-associated AKI is associated with a significant delay in recovery of renal function when compared to AKI from other causes (3). The etiology of AKI is multifactorial, with hypotension, systemic inflammation, and mechanical ventilation-associated hemodynamic alterations all playing a role. Other factors implied in AKI include rhabdomyolysis, thrombotic microangiopathy, and direct SARS-CoV-2 transduction of tubular epithelial cells. AKI in COVID-19 has been shown to be independent of severity of illness, suggesting that direct viral involvement or other unmeasured inflammatory mediators may play a role in inciting kidney injury (4).
During subsequent surges in COVID-19 infections in the United States, the incidence of AKI was significantly lower, and studies are underway to understand the declining rates of AKI with COVID-19 (5, 6). Possible explanations for lower incidence of AKI in subsequent surges include early use of dexamethasone and remdesivir, increased use of non-invasive ventilation (e.g., bi-level positive airway pressure [BiPAP]), and patients with fewer comorbidities.
The term “acute kidney care” refers to the provision of nephrology care as well as KRT to hospitalized patients, whether with AKI, chronic kidney disease (CKD), or end stage kidney disease (ESKD). Hospitals rapidly adapted their KRT programs to allow for provision of KRT to large numbers of patients, implementing prolonged, intermittent KRT utilizing continuous KRT (CKRT) machines (allowing two to three patients to be treated with a single machine) and adopting peritoneal dialysis (previously not utilized for adult patients with AKI) in the ICU. Utilization of existing and implementation of new anti-coagulation protocols for CKRT became essential, as hypercoagulability is extremely common with COVID-19. Even with a lower incidence of AKI, hospitals and nephrologists have to remain vigilant and prepared to provide KRT as hospitals face additional surges during the COVID-19 pandemic. For example, even in late 2021, as hospitals in Texas became inundated with large numbers of patients, those who needed KRT could not be transferred from smaller hospitals to larger centers that provide KRT due to a systemwide shortage of staffed beds.
The omicron variant of SARS-CoV-2spread rapidly across the African continent and in Europe and is now in North America. Data regarding the severity of illness, risk of hospitalization, and efficacy of vaccines against omicron remain murky. The ASN COVID-19 Task Force and Acute Kidney Care Committee continue to keep abreast of the latest developments and disseminate information and education to the kidney community on a regular basis. We strongly recommend that nephrology directors of inpatient services support disaster and planning committees and lead the way to advocate for adequate staffing and resources for inpatient kidney care (Figure 1) (7). Nephrology leadership must anticipate the need for KRT as we head into 2022 and ensure that adequate personnel, equipment, and supplies are available to provide care for every patient who will benefit from nephrology services and KRT.
Ng JH, et al. Outcomes among patients hospitalized with COVID-19 and acute kidney injury. Am J Kidney Dis 2021; 77:204–215.e1. doi: 10.1053/j.ajkd.2020.09.002
Nugent J, et al. Assessment of acute kidney injury and longitudinal kidney function after hospital discharge among patients with and without COVID-19. JAMA Netw Open 2021; 4:e211095. doi: 10.1001/jamanetworkopen.2021.1095
Moledina DG, et al. The association of COVID-19 with acute kidney injury independent of severity of illness: A multicenter cohort study. Am J Kidney Dis 2021; 77:490–499.e1. doi: 10.1053/j.ajkd.2020.12.007
Charytan DM, et al. Decreasing incidence of acute kidney injury in patients with COVID-19 critical illness in New York City. Kidney Int Rep 2021; 6:916–927. doi: 10.1016/j.ekir.2021.01.036
Dellepiane S, et al. Acute kidney injury in patients hospitalized with COVID-19 in New York City: Temporal trends from March 2020 to April 2021. Kidney Med 2021; 3:877–879. doi: 10.1016/j.xkme.2021.06.008
Nadim MK, et al. COVID-19-associated acute kidney injury: Consensus report of the 25th Acute Disease Quality Initiative (ADQI) Workgroup. Nat Rev Nephrol 2020; 16:747–764. doi: 10.1038/s41581-020-00356-5