Association of acute kidney injury with 1-year outcome of kidney function in hospital survivors with COVID-19: A cohort study

BACKGROUND: Kidney damage in COVID-19 patients has been of special concern. The association of acute kidney injury (AKI) with post-acute kidney function among COVID-19 survivors was not sufficiently elucidated. METHODS: An ambidirectional cohort study was conducted with enrollment of COVID-19 survivors discharged from hospital between Jan 7, and May 29, 2020. Study participants were invited to follow-up visits at 6 and 12 months after symptom onset. The primary outcome was percentage of estimated glomerular filtration rate (eGFR) decreased from acute phase (between symptom onset and hospital discharge) to follow-up, and secondary outcome was reduced renal function at follow-up. FINDINGS: In total, 1,734 study participants were included in this study. Median follow-up duration was 342.0 days (IQR, 223.0-358.0) after symptom onset. After multivariable adjustment, percentage of eGFR decreased from acute phase to follow-up was 8.30% (95% CI, 5.99-10.61) higher among AKI participants than those without AKI at acute phase. Participants with AKI had an odds ratio (OR) of 4.60 (95% CI, 2.10-10.08) for reduced renal function at follow-up. The percentage of eGFR decreased for participants with AKI stage 1, stage 2, and stage 3 was 6.02% (95% CI, 3.48-8.57), 15.99% (95% CI, 10.77-21.22), and 17.79% (95% CI, 9.14-26.43) higher compared with those without AKI, respectively. INTERPRETATION: AKI at acute phase of COVID-19 was closely related to the longitudinal decline and post-acute status of kidney function at nearly one-year after symptom onset. Earlier and more intense follow-up strategies on kidney function management could be beneficial to COVID-19 survivors. FUNDING: Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences (CIFMS 2020-I2M-CoV19-005, 2018-I2M-1-003, and 2020-I2M-2-013); National Natural Science Foundation of China (82041011); National Key Research and Development Program of China (2018YFC1200102); Major Projects of National Science and Technology on New Drug Creation and Development of Pulmonary Tuberculosis (2020ZX09201001).