Clinical predictors of acute cardiac injury and normalization of troponin after hospital discharge from COVID-19

Abstract

Background: Although acute cardiac injury (ACI) is a known COVID-19 complication, whether ACI acquired during COVID-19 recovers is unknown. This study investigated the incidence of persistent ACI and identified clinical predictors of ACI recovery in hospitalized patients with COVID-19 2.5 months post-discharge.

Methods: This retrospective study consisted of 10,696 hospitalized COVID-19 patients from March 11, 2020 to June 3, 2021. Demographics, comorbidities, and laboratory tests were collected at ACI onset, hospital discharge, and 2.5 months post-discharge. ACI was defined as serum troponin-T (TNT) level >99th-percentile upper reference limit (0.014ng/mL) during hospitalization, and recovery was defined as TNT below this threshold 2.5 months post-discharge. Four models were used to predict ACI recovery status.

Results: There were 4,248 (39.7%) COVID-19 patients with ACI, with most (93%) developed ACI on or within a day after admission. In-hospital mortality odds ratio of ACI patients was 4.45 [95%CI: 3.92, 5.05, p<0.001] compared to non-ACI patients. Of the 2,880 ACI survivors, 1,114 (38.7%) returned to our hospitals 2.5 months on average post-discharge, of which only 302 (44.9%) out of 673 patients recovered from ACI. There were no significant differences in demographics, race, ethnicity, major commodities, and length of hospital stay between groups. Prediction of ACI recovery post-discharge using the top predictors (troponin, creatinine, lymphocyte, sodium, lactate dehydrogenase, lymphocytes and hematocrit) at discharge yielded 63.73%-75.73% accuracy.

Interpretation: Persistent cardiac injury is common among COVID-19 survivors. Readily available patient data accurately predict ACI recovery post-discharge. Early identification of at-risk patients could help prevent long-term cardiovascular complications.

Funding: None.

Keywords: Machine learning; SARS-CoV-2; acute myocardial injury; heart failure.

Figure 1

Flowchart of hospitalized COVID-19 patients in the Montefiore Health System who recovered and who did not at 2.5 months post discharge (March 11, 2020 to June 3, 2021). ACI: acute cardiac injury.

Figure 2

Histograms of TNT level (a) at ACI diagnosis, (b) at discharge, (c) at 3 months post discharge, and (d) changes in TNT between 3 months post discharge and discharge separated by patients who recovered from ACI (blue) and those who did not (orange).

Figure 3

Predictive models at discharge using CART, Random Forest and neural network at discharge. For CART, R: recovery, NR: non-recovery. In the CART panel, the % within the box indicates % of total patients that arrived at each leaf, and the fractions within the box panel indicate actual non-recovery (right) and recovery (left). HR: heart rate.

Figure 4

Bar charts of top predictors of ACI at ACI diagnosis, hospital discharge and 2.5 months post discharge. Sample sizes are shown for each group with error bars as standard errors. This figure highlights some top predictors in graphical forms with statistical tests for these variables provided in Table 1.