SARS-CoV-2–containing MKs are associated with mortality and severe adverse events in COVID-19. (A) Spearman correlation analysis of continuous candidate model variables and cumulative 60-day postadmission outcomes for each patient (respiratory failure, mechanical ventilation, acute kidney injury, thrombotic events, ICU admission, and death). Each patient was limited to the first occurrence of a given outcome, resulting in a cumulative outcome maximum of 6. Statistical significance was assessed using Spearman correlation with Bonferroni P value adjustment for multiple hypothesis testing between candidate variables (X = nonsignificant; bold text, P value < .05). (B) Analyses comparing the WHO scale of COVID-19 severity on the day of sample collection (left) and peak severity during the entire inpatient stay (right) vs the circulating MK frequency for each subpopulation (∗ indicates intragroup and # indicates intergroup; ∗/# = 0.05-0.01, ∗∗/## = 0.01-0.001, ∗∗∗/### = 0.001-0.0001, ∗∗∗∗/#### < 0.0001). (C) Multivariate logistic regression models showing the likelihood of selected 30-day outcomes per 20% increase in each MK subpopulation (3 models per outcome; age, body mass index, and preadmission Charlson comorbidity score covariables not shown). Bootstrapped 95% CIs (n = 1000 bootstraps) are denoted as a bar to the right and left of each corresponding adjusted OR square. Event rates for each outcome are shown above each set of models. Statistical significance was assessed using the Wald test and is denoted by solid or open squares. Outcomes were determined using ICD-10 billing codes from each patient encounter. See supplemental Table 1 and supplemental Figures 8-10 for a complete breakdown of outcome billing codes and supplemental Tables 2-4 for regression model details.