ABSTRACT
BACKGROUND: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has a remarkable kidney tropism. While kidney affection is common in severe coronavirus disease-2019 (COVID-19), data on non-severe courses is limited. Here we provide a multilevel analysis of kidney outcomes after non-severe COVID-19 to test for eventual kidney sequela. METHODS: This cross-sectional study investigates individuals after COVID-19 and matched controls recruited from the Hamburg City Health Study (HCHS) and its COVID-19 program. The HCHS is a prospective population-based cohort study within the city of Hamburg, Germany. During the COVID-19 pandemic the study additionally recruited subjects after PCR-confirmed SARS-CoV-2 infections. Matching was performed by age, sex, and education. Main outcomes were eGFR, albuminuria, Dickkopf3, hematuria, and pyuria. RESULTS: 443 subjects in median 9 months after non-severe COVID-19 were compared to 1328 non-COVID-19 subjects. Mean eGFR was mildly lower in post-COVID-19 than non-COVID-19 subjects, even after adjusting for known risk factors (beta -1.84, 95%-confidence interval (CI) -3.16 to -0.52). However, chronic kidney disease (OR 0.90, 95%-CI 0.48 to 1.66) or severely increased albuminuria (OR 0.76, 95%-CI 0.49 to 1.09) equally occurred in post-COVID-19 and non-COVID-19 subjects. Hematuria, pyuria, and proteinuria were also similar between the two cohorts suggesting no ongoing kidney injury after non-severe COVID-19. Further, Dickkopf3 was not increased in the post-COVID-19 cohort indicating no systematic risk for ongoing GFR decline (beta -72.19, 95%-CI -130.0 to -14.4). CONCLUSIONS: While mean eGFR was slightly lower in subjects after non-severe COVID-19, there was no evidence for an ongoing or progressive kidney sequela.