The inflammatory markers of multisystem inflammatory syndrome in children (MIS‐C) and adolescents associated with COVID‐19: A meta‐analysis.

To conduct a systematic review and meta‐analysis to characterize inflammatory markers in comparisons of multisystem inflammatory syndrome in children (MIS‐C) versus severe/non‐severe COVID‐19, severe MIS‐C versus non‐severe MIS‐C, and among age groups of MIS‐C. Nine databases were searched for studies on inflammatory markers of MIS‐C. After quality checks, data were pooled using a fixed or random effects model. Inflammatory markers included white blood cell count (WBC) or leukocytes, absolute lymphocyte count (ALC), absolute neutrophil count (ANC), platelet count (PLT), C‐reactive protein (CRP), procalcitonin (PCT), ferritin, D‐dimer, lactate dehydrogenase (LDH), fibrinogen, and erythrocyte sedimentation rate (ESR) for comparisons by severity and age. Twenty‐one studies with 1735 participants yielded 787 MIS‐C patients. Compared to non‐severe COVID‐19 patients, MIS‐C patients had lower ALC and higher ANC, CRP, and D‐dimer levels. Compared to severe COVID‐19 patients, MIS‐C patients had lower LDH and PLT counts and higher ESR levels. Severe MIS‐C patients had higher levels of WBC, ANC, CRP, D‐dimer, and ferritin than non‐severe MIS‐C patients. For MIS‐C, younger children (0–5 years) had lower CRP and ferritin levels than middle‐aged/older children/adolescents. Measurement of inflammatory markers might assist clinicians in accurate evaluation and diagnosis of MIS‐C and the associated disorders. Research Highlights: •To conduct a comprehensive characterization of the inflammatory markers of MIS‐C during the COVID‐19 pandemic.•This meta‐analysis summarized the available data and demonstrated significant implications by characterizing the laboratory inflammatory markers of MIS‐C that has widely emerged as a major complication among children with COVID‐19.•The results indicated that inflammatory markers, including WBC, ALC, ANC, PLT, CRP, PCT, ferritin, D‐dimer, LDH, fibrinogen, and ESR, were different while comparing MIS‐C versus severe/non‐severe COVID‐19, severe MIS‐C versus non‐severe MIS‐C, and age groups of MIS‐C. [ABSTRACT FROM AUTHOR]