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Meta-Analysis
. 2022 Aug:58:281-285.
doi: 10.1016/j.ajem.2022.06.030. Epub 2022 Jun 22.

Significant association between anemia and higher risk for COVID-19 mortality: A meta-analysis of adjusted effect estimates

Ying Wang  1 , Lan Nan  2 , Mengke Hu  1 , Ruiying Zhang  1 , Yuqing Hao  3 , Yadong Wang  4 , Haiyan Yang  5
Affiliations
Meta-Analysis

Significant association between anemia and higher risk for COVID-19 mortality: A meta-analysis of adjusted effect estimates

Ying Wang et al. Am J Emerg Med. 2022 Aug.

Abstract

Objective: This study aimed to evaluate whether there was a significant relationship between anemia and the risk for mortality among coronavirus disease 2019 (COVID-19) patients by a quantitative meta-analysis based on the adjusted effect estimates.

Methods: A systematic search was conducted in electronic databases to identify all published literature. A random-effects meta-analysis model was used to estimate the pooled effect size and 95% confidence interval (CI). Heterogeneity test, Begg's test, subgroup analysis and meta-regression were performed.

Results: Twenty-three articles with 573,928 COVID-19 patients were included in the quantitative meta-analysis. There was a significant association between anemia and an elevated risk of COVID-19 mortality (pooled effect size = 1.47, 95% CI [1.30-1.67]). We observed this significant association in the further subgroup analyses by age, proportion of males, sample size, study design, region and setting. Sensitivity analysis exhibited that our results were reliable. Begg's test showed that there was no publication bias. Meta-regression indicated that the tested variables might not be the source of heterogeneity.

Conclusion: Our meta-analysis based on risk factors-adjusted effect estimates indicated that anemia was independently associated with a significantly elevated risk for mortality among COVID-19 patients.

Keywords: Anemia; COVID-19; Hemoglobin; Mortality; meta-analysis.

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Conflict of interest statement

Declaration of Competing Interest All authors declare that they have no any potential conflict of interest.

Figures

Fig. 1
Fig. 1
Flow chart of the process of study selection.
Fig. 2
Fig. 2
The forest plots indicated that there was a significant association between anemia and an elevated risk for mortality among patients with coronavirus disease 2019 (COVID-19) on the basis of twenty-three studies with 573,928 cases (A); Leave-one-out sensitivity analysis demonstrated the stability of the overall results (B); Begg's test revealed that there was no obvious publication bias (C).
See this image and copyright information in PMC

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