ABSTRACT
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.
ABSTRACT
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.