Possible role of higher serum level of myoglobin as predictor of worse prognosis in Sars-Cov 2 hospitalized patients. A monocentric retrospective study.

Background: Limited data on myoglobin and infectious diseases are available. In this study, we evaluate the potential role of myoglobin in predicting poor outcome in patients with Sars-Cov2 pneumonia.

Methods: One hundred and twenty-one Sars-Cov 2 patients with an average age of 69.9 ± 13.2 years, and symptoms duration of 8.8 ± 7.9 days were enrolled in the study. At the admission, the serum levels of myoglobin, erythrocyte sedimentation rate, C reactive protein (CRP), procalcitonin, ferritin, creatine phosphokinase, creatinine, fibrinogen, d-dimers, lactic dehydrogenase, troponin (Tn-I), creatine kinase myocardial band (CK-MB), complement fractions C3 and C4, immunoglobulins, interleukin 6 were evaluated. We also assessed the patients' complete clinical history and performed a thorough physical examination including age, disease history, and medications.

Results: Twenty-four (20%) patients died, and 18 (15%) patients required intensive care. The mean time between symptoms onset and death was 12.4 days ± 9.1. Univariate analysis of the patients' data highlighted some independent risk factors for mortality in COVID-19, including higher neutrophils rate (HR: 1.171), lower lymphocyte rate (HR: 0.798), high CK-MB serum levels (HR: 1.6), high Tn-I serum levels (HR: 1.03), high myoglobin serum levels (HR: 1.014), Alzheimer (HR 5.8), and higher CRP values (HR: 1.011). Cox regression analysis model revealed that higher serum values of myoglobin (HR 1.003; 95%CI: 1.001-1.006; p = 0.01), and CRP (HR 1.012; 95% CI: 1.001-1.023; p = 0.035) could be predictors of mortality in COVID-19 patients. The value of the myoglobin level for predicting 28 days-mortality using ROC curve was 121.8 ng/dL. Lower survival rate was observed in patients with serum levels of myoglobin>121.8 ng/dL (84% vs 20% respectively, p = 0.0001).

Conclusion: Our results suggest that higher serum levels of myoglobin could be a considerable and effective predictor of poor outcomes in COVID-19 patients; a careful follow-up in these patients is strongly suggested. The possibility of enhancing these findings in other cohorts of COVID-19 patients could validate the clinical value of myoglobin as a biomarker for worse prognosis in COVID-19.