Acute kidney injury following multisystem inflammatory syndrome associated with SARS-CoV-2 infection in children: a systematic review and meta-analysis.

Introduction: Multisystem inflammatory syndrome (MIS-C) is a rare paediatric hyper-inflammatory disorder that occurs following SARS-CoV-2 infection. Acute kidney injury (AKI) occurs in approximately one-quarter to one-third of the patients with MIS-C and is associated with poor prognosis in critically ill children. This systematic review is aimed to evaluate the incidence of AKI, mortality, and the need for kidney replacement therapy (KRT) in patients with MIS-C.

Methods: We searched databases from Medline, EMBASE, Cochrane Register, and Google Scholar from December 2019 to December 2021 with our search strategy. Studies meeting the following criteria were included in this systematic review: (1) articles on AKI in MIS-C; (2) studies providing AKI in MIS-C and COVID-19 infection separately; (3) studies reporting outcomes such as mortality, KRT, serum creatinine; length of hospital/ICU stay.

Quality Assessment: The quality of the included studies was independently assessed by using the National Heart Lung and Blood Institute (NHLBI) quality assessment tool for cohort studies and case series.

Statistical Analysis: Outcomes and their 95% confidence intervals (CI) were reported if a meta-analysis of these outcomes was conducted. Heterogeneity was reported using I statistics, and heterogeneity ≥ 50% was considered high. We used Baujat's plot for the contribution of each study toward overall heterogeneity. In sensitivity analysis, the summary estimates were assessed by repeating meta-analysis after omitting one study at a time. Forest plots were used for reporting outcomes in each study and with their 95% CI. All statistical tests were performed using R software version 4.0.3.

Results: A total of 24 studies were included in this systematic review and of these, 11 were included in the meta-analysis. The pooled proportion of patients with MIS-C developing AKI was 20% (95% CI: 14-28%, I = 80%). Pooled proportion of death in children with MIS-C was 4% (95% CI: 1-14%; I = 93%). The odds of death in patients with AKI were 4.68 times higher than in patients without AKI (95% CI: 1.06-20.7%; I = 17%). The overall pooled proportion of MIS-C-induced AKI patients requiring KRT was 15% (95% CI: 4-42%; I = 91%).

Conclusion: Approximately one-fifth of children with MIS-C develop AKI which is associated with higher odds of death. PROSPERO registration: CRD42022306170 A higher resolution version of the Graphical abstract is available as Supplementary information.