SARS-CoV-2 Viral Load and Cardiac Injury are Independent and Incremental Predictors of Adverse Outcome.

Objective: To evaluate the association of the SARS-CoV-2 initial viral load (iVL) and the incidence of myocardial injury (MCI) in hospitalized patients with SARS-CoV-2 infection. Patients and Methods: This is a retrospective longitudinal study of hospitalized patients who had a nasopharyngeal swab sample on admission that returned positive for SARS-CoV-2 by polymerase chain reaction between April 4 and June 5, 2020. The cycle threshold (Ct) value was used as a surrogate for the iVL level, with a Ct level ≤36 for elevated iVL, and >36 for low iVL. MCI was defined as having an elevated high-sensitivity cardiac troponin I >99th percentile upper reference limit. Results: A total of 270 patients were included. Of these, 171 (63.3%) had an elevated iVL and 88 (32.6%) had MCI. There was no significant difference in the incidence of MCI in patients with low iVL compared to those with elevated iVL (28.3% vs 35.1%, p=0.25). In a multivariable model, MCI (OR: 3.86; 95% CI 1.80-8.34, p<0.001) and elevated iVL (OR: 4.21; 95% CI 2.06-8.61, p<0.001) were independent and incremental predictors of in-hospital mortality. Conclusion: SARS-CoV-2 iVL level is not associated with increased incidence of MCI, though both parameters are strong independent and incremental predictors of mortality. Understanding the MCI mechanisms MCI allows for early focused interventions to improve survival, especially in patients with SARS-CoV-2 infection and high iVL.