The effect of low serum calcium level on the severity and mortality of Covid patients: A systematic review and meta-analysis

Introduction: Imbalances of various electrolytes, including calcium, are associated with the prognosis of Covid disease. This study investigated the relationship between serum calcium and clinical outcomes in patients with COVID-19. Method: This study is a systematic review and meta-analysis by searching PubMed, Scopus, web of sciences until August 2021 using the keywords COVID-19, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), COVID, coronavirus disease, SARS-COV-infection. 2, SARS-COV-2, COVID19, calcium, calcium isotopes, calcium radioisotopes, hypercalcemia, and hypocalcemia were performed. Heterogeneity of studies was investigated using I-2 index, data were analyzed using meta-analysis (random effects model) with Comprehensive Meta-Analysis Software software. Results: Finally, 25 articles were included in the study. Clinical data from 12 articles showed that 59% (95% confidence interval [CI]: 0.49-0.68) of people with COVID-19 have hypocalcemia. The results of meta-analysis showed that hypocalcemia was significantly associated with severity of the disease (p = .002), mortality in patients with COVID-19 (odds ratio [OR] = 6.99, 95% CI: 2.71-17.99), number of hospitalization days (p < .001) and admission to the intensive care unit (OR = 5.09, 95% CI: 2.14-12.10). The results also showed that there is a direct relationship between low serum calcium levels with increasing D-dimer levels (p = .02) and decreasing lymphocyte counts (p = .007). Conclusion: Based on the results of meta-analysis in people with lower calcium, mortality and complications are higher, therefore, serum calcium is a prognostic factor in determining the severity of the disease. Consequently, it is suggested that serum calcium levels should be considered in initial assessments.

Automated summary

This study found a significant association between hypocalcemia and severity of disease, mortality, hospitalization days, and admission to the intensive care unit in COVID-19 patients. Additionally, low serum calcium levels were found to be directly related to increasing D-dimer levels and decreasing lymphocyte counts. Consideration of serum calcium levels in initial assessments is recommended for determining disease severity.