Introduction
The outcomes of adults who develop an acute kidney injury (AKI) in the context of COVID-19 infection is unclear. We explored the epidemiology of AKI as well as exploring the risks associated with advancing age and intensive care admission.
Methods
Data was retrospectively collected on 481 COVID-19 positive (on swab) adult inpatients between 26th April 2020 and 4th June 2020. The data gathered from electronic patient records at our secondary care hospital included serial s. creatinine, demographics, comorbidities and AKI status. Excel was used to calculate means and standard deviations of various results. Patients on dialysis were excluded.
Results
There were 481 patients in total, the mean age was 72 (+- 16.9 ) years. The serum creatinine (median and range) in patients at admission, peak and discharge or death was 123 (range 30-1339), 136 (30-1339), 105 (7-761) umol/L.
200/481 patients (41.6%) had an AKI during their stay whilst 281 patients (58.4%) had no AKI. 3 patients had functioning renal grafts.
Of patients with AKI ,126/481 (26.2%) had AKI 1, 41/481 (8.5%) had AKI 2 and 33/481 (6.9%) had AKI 3. The overall mortality rate for those patients who developed an AKI was 106/200 (53%) compared to 58/281 (20.6%) for those with no AKI. The mortality rate for AKI1 was 56/126 (44.4%), for AKI 2 was 24/41 (58.54%) and for AKI3 was 23/31 (78.8%). The mean age of those who died with an AKI-1, AKI-2 and AKI-3 was 80 (+-10.3) years, 81.7 (+-13.0) years and 75.2 (+-11.5) years respectively.
Of the patients admitted with a functioning renal graft 1/3 (33.3%) patients did not survive admission.
Of those with an AKI 111/200 (55.5%) had recovery (<1.25x baseline creatinine on discharge or death) whilst 89.5/200 (44.5%) did not. Of those with an AKI who died, 45/106 (59.4%) had recovery prior to death. The mean age for those recovering from AKI was 75.0 (+-15.2) years compared to 78.2 (+-15.2) years for those who did not recover.
In total 35 patients were admitted to intensive care. the mortality rates for these patients was 18/35 (51.4%). Of these patients 22 had an AKI with a mortality rate of 16/22 (72.7%). The mortality rate for patients with an AKI-1 requiring ITU admission was of 2/5 (40%), 5/6 (83.3%) for AKI 2 and ITU admission and 9/11 (81.8%) for AKI3 with ITU admission. 9 patients admitted to intensive care required acute hemofiltration, mortality rate was 7/9 (77.78%). A further 37 patients required Continuous Positive airway pressure, the mortality rate for these patients was 16/37 (43.2%)
Mortality rate and frequency of developing AKI varied by age with 0/50 (0%) mortality rate for those between 18-50 years old increasing to 2/3 (66.7%) in those over 100. See bar chart for full data set.
The overall. mortality for inpatients admitted with COVID-19 was 164/481 (34.1%). In our patient set 277 (57.7%) were male and 204 (42.3%) were female. The mortality rate for females was 63/203 (31.0%) and for males was 101/278 (36.3%).
Conclusions
Patients with COVID-19 who developed an AKI had poorer outcomes than those who did not develop an AKI, especially if they required intensive care. Patient with advanced age also had a poor prognosis.
No conflict of interest