Since December 2019, coronavirus disease 2019 (COVID-19) has caused a global pandemic
with thousands of pneumonia-related deaths.
1
Recently, Wang et al
2
reported the existence of myocardial injury in 7.2% of all patients with COVID-19
and in 22.2% of patients admitted to the intensive care unit versus only 2.0% patients
not treated in the intensive care unit. Thus, we hypothesized that cardiac troponin
I (cTNI), an established biomarker of cardiac injury, may be a clinical predictor
of outcomes for patients with COVID-19.
Patients with laboratory-confirmed COVID-19 admitted to Union Hospital (West Campus),
Huazhong University of Science and Technology from January 12 to March 12, 2020, were
enrolled, and the final date of follow-up was March 20, 2020. This study was approved
by the ethics committee of Union Hospital, Huazhong University of Science and Technology
([2020]0087) and conducted in accordance with the guidelines of the Declaration of
Helsinki. Written informed consent was waived by the ethics commission based on the
retrospective nature of the study and the emerging worldwide crisis caused by this
infectious disease.
A total of 311 laboratory-confirmed COVID-19 cases were included on the basis of available
cTNI concentrations measured during hospitalization. The data of laboratory and imaging
tests performed for the first time after admission were used for analysis. The ARCHITECTSTAT
high-sensitivity troponin I assay (Abbott Laboratories) was used to measure cTnI concentrations.
3
Cardiac injury was diagnosed if the level of serum cTNI with at least 1 value was
above the 99th percentile upper reference limit during hospitalization. We defined
the severity of COVID-19 on admission by using the Chinese management guideline for
COVID-19 (version 6.0).
4
The primary composite end point was all-cause death. The included patients were assigned
to 1 of 2 groups according to clinical outcomes: the discharged group and the nonsurvivor
group. To explore the risk factors associated with mortality, univariable and then
multivariable logistic regression models (backward elimination) were applied. We chose
age, sex, comorbidity, body temperature, blood oxygen saturation, disease severity,
lymphocyte count, D-dimer, C-reactive protein, and cTNI as the 10 variables for our
multivariable logistic regression model on the basis of our univariable analysis results
and previous findings.
4
With the exception of age and blood oxygen saturation, the continuous variables of
laboratory and imaging indicators were included with log2 transformation and report
odds ratio (OR) per doubling of concentration (Table). A 2-tailed P<0.05 was considered
to be statistically significant. All analyses were performed with SPSS version 13.0
(SPSS).
Table.
Risk Factors for Mortality in Patients With COVID-19 by Univariable and Multivariable
Analysis
For 311 included patients, the median age was 63 years (interquartile range [IQR],
54–70 years), and 190 (61.1%) patients were male. Overall, 62.7% of patients had at
least 1 comorbidity, including hypertension, cardiovascular disease (coronary heart
disease/arrhythmia/heart failure), cerebrovascular disease, chronic obstructive pulmonary
disease, diabetes mellitus, malignancy, chronic kidney disease, and thyroid disease.
The most common symptoms on admission were fever (77.5%), cough (32.5%), and dyspnea
(24.4%). With regard to disease severity on admission, there were 101 patients (32.5%)
with moderate-type, 180 (57.9%) with severe-type, and 30 (9.6%) with critical-type
COVID-19. One hundred eleven patients died during hospitalization and 200 were discharged.
The median time from illness onset to death was 23 days (IQR, 15–32 days). In laboratory
findings, the lymphocyte count (0.5×109/L [IQR, 0.4–0.8×109/L] versus 1.2×109/L [IQR,
0.9–1.7×109/L]) was lower in the nonsurvivor group than in the discharged group. The
concentrations of D-dimer (4.0 µg/mL [IQR, 1.2–8.0 µg/mL] versus 0.5 µg/mL [IQR, 0.2–1.5µg/mL]),
C-reactive protein (80.2 mg/L [IQR, 48.4–121.8 mg/L] versus 8.1 mg/L [IQR, 2.4–43.6
mg/L]), and cTNI (32.5 ng/L [IQR, 11.4–304.4 ng/L] versus 2.8 ng/L [IQR, 1.5–5.8 ng/L])
in the nonsurvivor group were elevated in comparison with those in the discharged
group. There were 103 patients (33.1%) with cardiac injury, including 12 patients
in the discharged group and 91 patients in the nonsurvivor group. Multivariable logistic
regression analysis identified cTNI concentration (OR, 1.92 [95% CI, 1.41–2.59]),
lymphocyte count (OR, 0.52 [95% CI, 0.29–0.95]), C-reactive protein concentration
(OR, 1.98 [95% CI, 1.34–2.92]), D-dimer concentration (OR, 1.55 [95% CI, 1.13–2.13]),
comorbidity (OR, 9.07 [95% CI, 2.52–32.66]), and blood oxygen saturation (OR, 0.85
[95% CI, 0.77–0.94]) as independent risk factors for death in patients with COVID-19
(Table).
Although respiratory symptoms are the primary clinical manifestations of COVID-19,
a portion of patients will experience severe cardiovascular injury.
2, 5
cTnI is the most important biomarker of cardiac injury. Our results indicate that
the serum cTnI concentration was significantly higher in nonsurviving patients with
severe acute respiratory syndrome coronavirus 2 infection than in discharged patients,
and the further multivariable logistic regression identified increased cTnI concentration
as an independent predictor of mortality in patients with COVID-19.
This study is limited by selection bias based on cTnI measurement. The determination
of whether cTnI would be measured in each case was an individual decision by the clinician.
The results do not totally represent the epidemiological data of COVID-19.
Disclosures
None.