ABSTRACT
BACKGROUND: Coronavirus disease 2019 (COVID-19) is an ongoing global pandemic. The ability to predict cardiac injury and analyze lymphocyte immunity and inflammation of cardiac damage in patients with COVID-19 is limited. We aimed to determine the risk factors and predictive markers of cardiac injury in these patients. METHODS: Data from 124 consecutive hospitalized patients with confirmed COVID-19 were collected. We compared the proportion of cardiovascular disease history in moderate, severe, and critical cases. We obtained high-sensitivity cardiac troponin I (hs-cTn I) results from 68 patients. Patients were divided into two groups based on positive hs-cTn I result: those with cardiac injury (n = 19) and those without cardiac injury (n = 49). RESULTS: Compared with the group with moderate disease, hypertension, coronary heart disease, and smoking were more common in severe and critical cases. Diabetes mellitus was most common in the critical group. Age older than 65 years, presence of chronic kidney disease, and lower blood lymphocyte percentage were independent risk factors of cardiac injury. The total T- and B-lymphocyte counts and CD4+ and CD8+ T-cell counts were significantly lower in those with cardiac injury. A minimal lymphocyte percentage < 7.8% may predict cardiac injury. The interleukin (IL) 6 level in plasma was elevated in the group with cardiac injury. CONCLUSIONS: The lymphocyte percentage in blood may become a predictive marker of cardiac injury in COVID-19 patients. The total T and B cells and CD4+ and CD8+ cell counts decreased and the IL-6 level increased in COVID-19 patients with cardiac injury.