To the editor:

Although acute kidney injury requiring kidney replacement therapy (AKI-KRT) is an important and severe complication in patients with coronavirus disease 2019 (COVID-19), data on its long-term outcomes are currently limited. Previous studies reported that 65% to 70% of patients with AKI-KRT had recovered from dialysis dependency at the time of hospital discharge.^{1 , 2} However, long-term renal outcomes are unknown, because post-hospital follow-up after COVID-19–associated AKI in previous studies was limited to short observational periods.^{1 , 3} We retrospectively analyzed renal outcomes in 74 hospitalized patients with COVID-19 and AKI-KRT in a large tertiary care center in Berlin, Germany, between March and June 2020. Patients were predominantly male (74.3%); the median age was 65 years; and the median baseline estimated glomerular filtration rate was 76.5 ml/min per 1.73 m² (Supplementary Table S1). All patients were treated in intensive care units at the time of AKI-KRT onset; 98.6% of patients were mechanically ventilated, and 39.2% received extracorporeal membrane oxygenation therapy. COVID-19–specific therapies included corticosteroids (68%), hydroxychloroquine (4.1%), anakinra (8.1%), immunoglobulins (6.8%), tocilizumab (1.4%), and lopinavir-ritonavir (1.4%) (Supplementary Table S1). On October 21, 2020, after a median follow-up of 151 days (interquartile range 128–192 days) post-initiation of KRT, 36 patients (48.6%) had died during hospitalization, 1 patient (1.4%) was still hospitalized, and 37 (50%) had been discharged. In discharged survivors, the median overall duration of KRT was 27 days (interquartile range 11–50 days). At the end of follow-up, 3 patients (8.1%) were KRT-dependent while the remaining 34 patients (91.9%) had achieved variable degrees of renal recovery, including 23 patients (62.2%) with full renal recovery (Figure 1 ; Supplementary Table S1). These findings indicate that renal recovery is common in COVID-19 survivors even after long periods of KRT requirement during AKI. This information may be of value for patients with COVID-19 and their clinicians when it comes to deciding about the initiation or continuation of KRT.

Figure 1

Renal outcomes after coronavirus disease 2019–associated acute kidney injury requiring kidney replacement therapy (KRT).(a) Cumulative incidence function for the end of first KRT, with death as a competing risk. (b) Renal outcome of discharged survivors at hospital discharge. (c) Renal outcome of discharged survivors at post-hospital follow-up (FU). (d,e) Course of dialysis dependency with daily patient data as stacked bar chart with (d) hospital admission or (e) start of KRT as the start date.