Long-term renal outcomes of patients with COVID-19: a meta-analysis of observational studies

BackgroundKidney involvement is common in hospitalized coronavirus disease 2019 (COVID-19) patients during the acute phase, little is known about the long-term impact of COVID-19 on the kidney.MethodsThis is a systematic review and meta-analysis on long-term renal outcomes among COVID-19 patients. We carried out a systematic literature search in PUBMED, EMBASE, SCOPUS, and Cochrane COVID-19 study register and performed the random-effects meta-analysis of rates. The search was last updated on November 23, 2022.ResultsThe study included 12 moderate to high-quality cohort studies involving 6976 patients with COVID-19-associated acute kidney injury and 5223 COVID-19 patients without acute kidney injury. The summarized long-term renal non-recovery rate, dialysis-dependent rate, and complete recovery rate among patients with COVID-19-associated AKI was 22% (12-33%), 6% (2-12%), and 63% (44-81%) during a follow-up of 90-326.5 days. Heterogeneity could be explained by differences in the prevalence of chronic kidney disease and proportion of acute kidney injury requiring renal replacement therapy using meta-regression; patients with more comorbidities or higher renal replacement therapy rate had higher non-recovery rates. The summarized long-term kidney function decrease rate among patients without acute kidney injury was 22% (3-51%) in 90-199 days, with heterogeneity partially explained by severity of infection.ConclusionPatients with more comorbidities tend to have a higher renal non recovery rate after COVID-19-associated acute kidney injury; for COVID-19 patients without acute kidney injury, decrease in kidney function may occur during long-term follow-up. Regular evaluation of kidney function during the post-COVID-19 follow-up among high-risk patients may be necessary.