Identification of immunological, inflammatory, hematological, and
coagulation abnormalities associated with severity and mortality of
COVID-19: a meta-analysis of 64 observational studies
Abstract
Background: Laboratory abnormalities associated with disease severity
and mortality in patients with coronavirus disease 2019 (COVID-19) have
been reported in many observational studies. However, there are
significant heterogeneities in patient characteristics and research
methodologies in these studies. Objectives: We aimed to provide an
updated synthesis of the association between laboratory abnormalities
and COVID-19 prognosis. Methods: We conducted an electronic search of
PubMed, Scopus, Ovid, Willey, Web of Science, and the China National
Knowledge Infrastructure (CNKI) for studies reporting hematological,
coagulation, inflammatory, and immunological results during hospital
admission of COVID-19 patients with different severities and outcomes.
Results: A total of 64 studies were included in the current
meta-analysis, with 8 hematological, 3 coagulation, 5 inflammatory, and
23 immunological variables reported. Of them, white blood cell (WBC) and
neutrophil counts, D-dimer level, procalcitonin (PCT), erythrocyte
sedimentation rate (ESR), C-reactive protein (CRP), ferretin, serum
amyloid A (SAA), interleukins (ILs)–2R, IL-6, and IL-10 were
significantly increased in severely ill patients and non-survivors.
Meanwhile, non-severely ill patients and survivors presented
significantly higher counts of eosinophils, lymphocytes, and CD4+ and
CD8+ T cells. Conclusions: The current meta-analysis provides a
comprehensive and updated synthesis of the association between admission
laboratory abnormalities with severity and mortality of COVID-19. Our
results highlight that increases in the levels of PCT, ESR, CRP,
ferretin, SAA, IL-2R, IL-6, and IL-10 were associated with disease
deterioration, whereas elevated eosinophils, lymphocytes, and T-cell
subsets might serve as indicators of favorable outcomes.