Serum cortisol concentration and COVID-19 severity: a systematic review and meta-analysis

The novel COVID-19 outbreak is a major health threat to human beings with multiorgan injuries. However, its endocrine system manifestations are much less studied. In this study, we aimed to reassess the available findings on the association between cortisol level and severity of COVID-19 infection. We conducted a systematic search on Medline/PubMed, Scopus, Web of Science, and Cochrane Library databases. To pool data, a random-effects model was performed depending on the heterogeneity among studies. Sensitivity analysis was also carried out by removing each study systematically. In addition, subgroup and meta-regression analyses were performed depending on the presence of the variables of sex and age. Subsequently, 11 studies (5 observational studies and 6 case reports) were included in the meta-analysis. Pooled analysis on the observational studies showed significantly higher levels of cortisol in patients with severe COVID-19 in comparison with those with mild-to-moderate COVID-19 (standardized mean difference: 1.48 µg/dL; 95% CI (0.51 to 2.46); p=0.003). Assessment of the results of case reports revealed that the patients with severe COVID-19 demonstrated higher cortisol levels than the patients with mild-to-moderate COVID-19. No publication bias was observed using the Begg's (p=0.08) and Egger's tests (p=0.09). Meta-regression illustrated a significant correlation between cortisol levels with sex. The serum cortisol level seems to be higher in patients with severe COVID-19 infection. This finding could be helpful to detect patients with poor prognosis at early stages of the disease, although age and sex may modify this level.