IS LYMPHOPENIA A PREDICTOR OF MORTALITY IN PATIENTS WITH COVID-19?

In this study, we evaluated the relation between the presence of lymphopenia and the need of intensive care unit (ICU) or mortality. A total of 1670 COVID-19 patients were divided according to the severity of lymphopenia developing at the time of COVID-19 infection. According to the symptoms and need of ICU, the infection was classified as mild or severe. The rates of severe infection, ICU admission, and mortality were evaluated between the groups. Among 1670 patients, 576 (34.4%) patients had severe disease and 1094 (65.6%) patients had a mild form of the disease; 213 (12.7%) patients with severe COVID-19 died. The severe form of COVID-19 was more common in patients with low lymphocyte levels (<500) than in those with normal lymphocytes count (64.7% vs. 5.2%; p<0.001). The odds ratio of lymphopenic patients was 2.4 (1.8-3.0; p=0.001). The risk of severe COVID-19 infection and mortality was 8.9 and 12.4 times higher in patients with low lymphocyte count compared to patients with normal lymphocyte count subsequently. ROC analysis showed that lymphocyte counts lower than 615 lym/mcL had 96.4% sensitivity for severe disease (AUC:0.89 (0.842-0.938); p<0.001). There was a significant negative correlation between lymphocyte count and mortality rate and severe COVID-19 disease (for severe COVID-19 r=-0.590; p<0.001and for mortality r=-0.511; p=0.001). In conclusion, we found a strong correlation between lymphopenia and COVID-19 outcomes. Lymphopenia in patients with COVID-19 was a prognostic factor in the course of the disease. Lymphopenia is an easy and inexpensive prognostic factor that can be used in the management of COVID-19 patients.