SARS-CoV-2 Viral Load and Myocardial Injury: Independent and Incremental Predictors of Adverse Outcome

To evaluate the association of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) initial viral load (iVL) and the incidence of myocardial injury (MCI) in hospitalized patients with SARS-CoV-2 infection, we conducted a retrospective longitudinal study of hospitalized patients who had a nasopharyngeal swab sample on admission that returned a positive result 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 of 36 or less for elevated iVL and greater than 36 for low iVL. Myocardial injury was defined as an elevated high-sensitivity cardiac troponin I level that was higher than the 99th percentile upper reference limit. 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 of 99 [28.3%] vs 60 of 171 [35.1%]; P=.25). In a multivariable model, MCI (odds ratio, 3.86; 95% CI, 1.80 to 8.34; P<.001) and elevated iVL (odds ratio, 4.21; 95% CI, 2.06 to 8.61; P<.001) were independent and incremental predictors of in-hospital mortality. The SARS-CoV-2 iVL level is not associated with increased incidence of MCI, although both parameters are strong independent and incremental predictors of mortality. Understanding the MCI mechanisms allows for early focused interventions to improve survival, especially in patients with SARS-CoV-2 infection and high iVL.