Kidney injury in COVID-19

Table 1 Summary of acute kidney injury incidence in coronavirus disease 2019 patients

Ref.	Zhou et al[2]	Yang et al[8]	Guan et al[4]	Wan et al[16]	Arentz et al[6]	Cheng et al[10]	Italian data March 20, 2020[7]	Combined results without Italian data	Combined results with Italian data
Total patients	191	52	1099	135	21	701	47021	2199	49220
Critically Ill1	50	52	55	40	21	73	N/A	291
ARDS	59 (30.1%)	35 (67%)	37 (3.4%)	20 (14.8%)	20 (95.2%)	974 (13%)	N/A	268 (12.2%)
AKI	28 (14.7%)	15 (28.8%)	6 (0.5%)	5 (3.7%)	4 (19%)	36 (5.1%)	N/A	94 (4.2%)
RRT	10 (5%)	9 (17.3%)	9 (0.85)	5 (3.7%)	N/A	N/A	N/A	33 (1.5%)
Non survivors (NS)2	54 (28.3%)	32 (61.5%)	672 (6.1%)	1 (0.7%)	11 (52.4%)	113 (16.1%)	3200 (6.8%)	278 (154)5 (12.6%)	3478 (3354) (7%)
AKI in NS2,3	27 (50%)	12 (37.5%)	42 (6%)	43 (10%)	N/A	N/A	944 (29.5%)	47 (30.5%)	991 (29.5%)
RRT in NS2,3	10 (18.5%)	8 (25%)	82 (11.9%)	43 (10%)	N/A	N/A	N/A	30(19.5%)

¹Critically ill is defined as intensive care unit (ICU) admitted or categorised as a severe case where separate ICU data are not provided by the primary authors.

²The study by Guan et al[4] (NEJM) includes patients in ICU admission, on mechanical ventilation and non-survivors.

³The study by Wan et al[16] includes patients with critical illness.

⁴Patients on mechanical ventilation.

⁵Excluding data from Arentz et al[6] and Cheng et al[10] as acute kidney injury incidence was not provided in non-survivors. AKI: Acute kidney injury; ARDS: Acute respiratory distress syndrome; RRT: Renal replacement therapy.

Table 2 Summary of the mechanism of kidney injury in coronavirus disease 2019

Mechanism of kidney injury	Hypovolaemia	ARDS related AKI	Cytokine storm syndrome associated AKI	Direct viral invasion
Pre-renal	Fever causing insensible losses; Gastrointestinal volume losses	Haemodynamic instability; High positive end expiratory pressure /intrathoracic pressure; Right heart failure	Haemodynamic instability
Renal1		Inflammation; Hypoxia/hypercapnia; Acid-base dysregulation; Tubular injury	Inflammation; Possible glomerulopathy and TMA ( hypercoagulability)	Inflammation; Possible Tubulopathy; Podocytopathy; Interstitial inflammation
Post renal

¹The most common intrinsic renal lesion observed is acute tubular necrosis. AKI: Acute kidney injury; ARDS: Acute respiratory distress syndrome; TMA: Thrombotic microangiopathy.