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.