Clinical course and outcomes of COVID-19 patients with biopsy-proven glomerular and tubular kidney disease. low hemoglobin levels as a risk factor for mortality

ABSTRACT

BACKGROUND AND AIMS: COVID-19 infection is responsible for respiratory infection with variable clinical expression from its asymptomatic form to severe pneumonia associated with acute respiratory distress syndrome and death. Risk factors related to higher mortality are age over 65 years, cardiovascular, pulmonary and kidney disease, hypertension, and diabetes. There is limited scientific literature on COVID-19 infection and previous kidney disease, specifically in patients with glomerular and tubular kidney disease. The aim of this study was to determine general characteristics, analytical parameters and clinical evolution of patients with kidney disease who have undergone kidney biopsy and who presented infection or high suspicion of infection by COVID-19. Identify mortality and associated risk factors. METHOD: we studied patients with high clinical suspicion of infection or confirmed infection by COVID-19 from March 2020 to May 15, 2020 of all patients who underwent percutaneous renal biopsy at the Vall d'Hebron Hospital between January 2013 and December 2019. RESULTS: 39 of the 553 patients have been diagnosed with COVID-19 infection since March 2020. The average age was 63615 years and 48.7% were male. Hypertension was present in 79.5% of patients, chronic kidney disease without renal replacement therapy in 76.9%, and cardiovascular disease in 64.1%. Nasopharyngeal swab was performed in 26 patients;older patients (p=0.01), patients with hypertension (p=0.005), immunosuppression (p=0.01), use of RAS-blocking drugs (p=0.04) and gastrointestinal symptoms (p=0.02) were more likely to be tested for COVID-19. 22 patients required hospitalization and 15.4% died. In the bivariate analysis, mortality was associated with older age (p=0.03), cardiovascular disease (p=0.05), chronic obstructive pulmonary disease (COPD) (p=0.05) and low hemoglobin levels (p=0.006). Adjusted Cox regression showed that low hemoglobin levels (10.12±1.89g/dL) at admission had 1.81 greater risk of mortality [1.04-3.13;p=0.04]. CONCLUSION: Patients with COVID-19 infection and kidney disease confirmed by kidney biopsy presented mortality of 15.4%. Swab test for COVID-19 was more likely to be performed in older, hypertensive, use of RAS-blocking drugs, immunosuppressed patients and those with gastrointestinal symptoms. Low hemoglobin is a risk factor for mortality.