Neutrophil to lymphocyte ratio patterns and the severity of COVID-19: A cross sectional study

The neutrophil-to-lymphocyte ratio (NLR), obtained from a peripheral blood sample, is considered an indicator of subclinical inflammation. The aim of this study was to determine the NLR pattern in the deceased and survivor patients with coronavirus disease 2019 (COVID-19) during hospitalization.

This was a cross-sectional analytical study that was performed in TohidHospital in Sanandaj, Iran, from March to July 2021. In our study, 30 patients had received the treatments for COVID-19 and did not need to be admitted to the intensive care unit (ICU). They were discharged from the hospital and considered "Group A". Besides, 21 patients who were admitted to the ICU but were discharged were considered "Group B". Finally, 40 patients with COVID-19 who were hospitalized in the ICU and died were considered "Group C". Complete blood count (CBC) test was performed for all patients at 3 different times (at the time of admission, mid-hospitalization, and the last day of hospitalization). In the end, the data were analyzed by one-way analysis of variance (ANOVA) and the Kruskal-Wallis H test.

91 patients were included in this study. The NLR index during hospitalization in Group C was significantly higher than in Group B and in Group B was significantly higher than in Group A. On the other hand, in Group C, the NLR was significantly increased at three consecutive times during hospitalization; however, in Group B and Group A, at the end of hospitalization, this ratio was lower than in mid-hospitalization.

The NLR was an important indicator in predicting patients' prognoses. Pulmonary inflammation in patients with COVID-19 will be accompanied dominantly by neutrophils; thus, the NLR parameter could be important in the progress of the clinical status.