Acute and chronic kidney disease and risk of hospital mortality during COVID-19 pandemic waves in the pre-vaccination era.

Background: Chronic kidney disease (CKD) is a risk factor for death from coronavirus disease 2019 (COVID-19), and COVID-19 may cause acute kidney injury (AKI) which also influences outcomes. There is little information on the independent contribution of CKD and AKI to the risk of death in COVID-19 on different waves, as CKD is a key risk factor for AKI. Methods: We have studied the epidemiology of CKD and AKI in 2878 patients hospitalized for COVID-19 and their independent association with in-hospital mortality in the two largest pre-vaccination COVID-19 waves in Madrid, Spain. Hospitalized COVID-19 patients were grouped into four mutually exclusive categories: previous-CKD, community-acquired AKI (CA-AKI), hospital-acquired AKI (HA-AKI) and normal renal function throughout hospitalization. Results: Pre-existent or acquired kidney involvement was observed in 35.5% and 36.8% of COVID-19 patients in the 1st and 3rd waves, respectively. Overall, 13.9% of patients with normal kidney function on arrival developed HA-AKI. In the 3rd wave, CA-AKI was more common than in the 1st wave. Overall, 9%-20% of CKD cases and 22%-40% of AKI cases remained undiagnosed in the discharge report. CKD, CA-AKI and HA-AKI were independently associated with risk of death in multivariate analysis, with HA-AKI, which was usually mild, being the most relevant independent risk factor for in-hospital mortality. A model including kidney involvement category, age, Charlson index, admission lactate dehydrogenase and lymphocytes predicted death with a receiver operating characteristic area under the curve of 0.898. Conclusion: In conclusion, CKD and AKI were common in pre-vaccination waves among hospitalized COVID-19 patients and were independent risk factors for death, even when AKI was mild to moderate, and despite improvements in treatment.

Effect of Expanded Hemodialysis with Theranova® in Patients with COVID-19.

INTRODUCTION: Cytokine storm control is the main target for improving severe COVID-19 by using immunosuppressive treatment. Effective renal replacement therapy (RRT) could give us an advantage removing cytokines in patients with RRT requirements superimposed on COVID-19. METHODS: This is a prospective observational study in COVID-19 patients who required hemodialysis (HD). Patients were assigned to online hemodiafiltration (OL-HDF) and expanded HD (HDx) according to Brescia group recommendations. We measured several cytokines, ß2 microglobulin and albumin levels pre/post-dialysis and on 1st-2nd week. We compared levels among both techniques and control group (HD without COVID-19). RESULTS: We included 26 patients: 18 with COVID-19 on RRT (5 of them had acute kidney injury [AKI]) and 8 controls. We confirm higher cytokine levels in COVID-19 patients than controls and even higher in patients with AKI than in those with chronic kidney disease. Most cytokines raised during HD session, except IL-10 and TNFα. IL-10 was eliminated by any dialysis technique, while clearance of TNFα was higher in the HDx group. HDx achieved a deeper normalization of cytokines and ß2 microglobulin reduction. Mortality was higher in the OL-HDF group than the HDx group. DISCUSSION: Not all cytokines behave equally along HD session. The following characteristics should be taken into account, such as intrinsic kinetic profile during a HD session. HDx seems to get better performance, probably due to the combination of different factors; however, we did not reach statistical significance due to the small sample size, dropout, and reduction of AKI incidence during the 2nd pandemic wave. CONCLUSION: HDx appears to provide better clearance for TNFα and ß2 microglobulin during HD session and associates lower mortality. We propose the HDx technique for COVID-19 patients with RRT requirements since it seems to be safe and more effective than OL-HDF. Further studies are still needed, but we hope that our preliminary data may help us in future pandemic waves of SARS-CoV-2 or other viruses still to come.

Rapid decline of anti-SARS-CoV-2 antibodies in patients on haemodialysis: the COVID-FRIAT study.

BACKGROUND: Coronavirus disease 2019 (COVID-19) patients on haemodialysis (HD) have high mortality. We investigated the value of reverse transcription polymerase chain reaction (RT-PCR) and the dynamic changes of antibodies (enzyme-linked immunosorbent assay immunoglobulin M (IgM) + IgA and/or IgG) in a large HD cohort. METHODS: We conducted a prospective observational study in 10 Madrid HD centres. Infection rate, anti-SARS-CoV-2 antibody dynamics and the incidence of asymptomatic SARS-CoV-2 infection (defined by positive RT-PCR, IgM + IgA and/or IgG) were assessed. RESULTS: From 1 March to 15 April 2020, 136 of 808 (16.8%) HD patients were diagnosed with symptomatic COVID-19 by RT-PCR of nasopharyngeal swabs and 42/136 (31%) died. In the second fortnight of April, RT-PCR and anti-SARS-CoV-2 antibodies were assessed in 763 of the surviving patients. At this point, 69/91 (75.8%) symptomatic COVID-19 patients had anti-SARS-CoV-2 antibodies. Four weeks later, 15.4% (10/65) of initially antibody-positive patients had become negative. Among patients without prior symptomatic COVID-19, 9/672 (1.3%) were RT-PCR positive and 101/672 patients (15.0%) were antibody positive. Four weeks later, 62/86 (72.1%) of initially antibody-positive patients had become negative. Considering only IgG titres, serology remained positive after 4 weeks in 90% (54/60) of patients with symptomatic COVID-19 and in 52.5% (21/40) of asymptomatic patients. The probability of an adequate serologic response (defined as the development of anti-SARS-CoV-2 antibodies that persisted at 4 weeks) was higher in patients who had symptomatic COVID-19 than in asymptomatic SARS-CoV-2 infection {odds ratio [OR) 4.04 [95% confidence interval (CI) 2.04-7.99]} corrected for age, Charlson comorbidity index score and time on HD. Living in a nursing home [OR 5.9 (95% CI 2.3-15.1)] was the main risk factor for SARS-CoV-2 infection. CONCLUSIONS: The anti-SARS-CoV-2 antibody immune response in HD patients depends on clinical presentation. The antibody titres decay earlier than previously reported for the general population. This inadequate immune response raises questions about the efficacy of future vaccines.

Chronic kidney disease and acute kidney injury in the COVID-19 Spanish outbreak.

BACKGROUND: Novel coronavirus disease 2019 (COVID-19) emerged in Wuhan and rapidly spread, affecting >10 million cases worldwide. Caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and primarily manifesting as an acute respiratory failure with interstitial and alveolar pneumonia, it can also affect multiple organs. Kidney involvement was underestimated in early reports and its role remains controversial. The aim of this study was to analyse the role of kidney damage in COVID-19 outcome. METHODS: This is a prospective cohort study of 1603 consecutive patients admitted in a University Reference Hospital in the heart of the European outbreak. RESULTS: Median age was 64 years, 40.4% were female, 15.2% presented diabetes mellitus, 35.7% hypertension and 20.3% obesity. On admission, the prevalence of elevated serum creatinine (sCr), proteinuria, leucocyturia and haematuria were 21.0, 37.8, 31.8 and 45.6%, respectively. In total, 43.5% of those with an elevated sCr had previous chronic kidney disease (CKD) and 11.4% of those with normal sCr developed an in-hospital acute kidney injury (AKI); 17 patients needed acute haemodialysis; and 197 patients died during hospitalization. Cox proportional hazard regression confirmed that elevated baseline sCr [hazard ratio (95% confidence interval) 2.40 (1.79-3.22)], previous CKD [1.59 (1.06-2.37)], haematuria [1 + 1.68 (0.92-3.06), 2-3 + 2.69 (1.49-4.87)] and in-hospital AKI [1.50 (0.92-2.44)] were independent risk factors for in-hospital death after adjusting for age, sex and comorbidity. CONCLUSION: The prevalence of acute and chronic kidney disease on admission and in-hospital AKI is higher than previously reported in Wuhan, and is associated with high in-hospital mortality. We should increase our awareness towards kidney involvement and design specific strategies for management of COVID-19 in these patients.