Investigation of the relationship between lymphopenia and the severity of the disease in patients followed in the intensive care unit due to COVİD-19 disease

Lymphopenia can be seen in patients because of Coronavirus Disease 2019 (COVID-19), and lymphopenia is more common in patients who died from COVID-19. In literature, there are studies that were showing relationships between lymphopenia and severity of COVID-19. But there is no study showing the relationship between lymphopenia and Acute Physiology and Chronic Health Assessment II (APACHE II), Sequential Organ Failure Assessment (SOFA) scores that showing disease severity and mortality in patients followed up for COVID-19 in the intensive care unit. In this study, we evaluated the relationship between lymphopenia and severity and mortality of the disease in patients who needed intensive care due to COVID-19. We aimed to identify an inexpensive and easy biomarker to identify severe disease among hospitalized patients in the early stages. In this study, patients in need of intensive care unit due to COVID-19 were scanned retrospectively from the hospital file system. 50 patients were 18-80 years old and they have the exclusion criterias and were followed in the intensive care unit were included in these study. It was statistically evaluated whether there was a correlation between the number of lymphocytes checked on the day of admission to the intensive care unit and the APACHE II, SOFA scores of these patients. There was no significant difference between the mean lymphocyte counts of patients who died due to COVID-19 and the mean lymphocyte counts of patients who survived (p>0.05). No correlation was found between the mean lymphocyte count of the patients and their APACHE II scores (p>0.05, r<0.30). No correlation was found between the mean lymphocyte count and SOFA scores of the patients (p>0.05, r<0.30). There was no significant difference between the survival chances of patients with and without lymphopenia (p>0.05). In this study, it was determined that there was no relationship between lymphopenia and the mortality of the disease in patients who needed intensive care due to COVID-19. APACHE II and SOFA scores were found to significantly predict mortality in these patients. In addition, patients with an APACHE II score ≥ 15.5 or a SOFA score ≥ 4.5 had a high mortality rate. The APACHE II score ≥ 15.5 led to an excellent mortality estimate. SOFA score ≥ 4.5 led to a very good mortality estimate.