Predictive value of immature granulocyte count and other inflammatory parameters for disease severity in COVID‐19 patients

INTRODUCTION: This study was designed to compare the immature granulocyte (IG) count, IG-to-lymphocyte ratio (IGLR), complete blood count (CBC) values, and inflammatory parameters of neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), C-reactive protein (CRP), ferritin level, and CRP-to-albumin ratio (CAR) measured at hospital admission in patients with coronavirus disease 2019 (COVID-19) and non-COVID-19 patients and to compare these parameters between subgroups according to disease severity. In addition, these parameters were evaluated for predictive value related to the severity of COVID‐19.
METHODS: The data of adult patients admitted with a suspected COVID-19 infection confirmed with real-time polymerase chain reaction testing of nasal and pharyngeal swab specimens were included in this retrospective study. Outpatient COVID-19-positive patients were enrolled in the mild group, hospitalized patients were classified in the moderate group, and patients admitted to the intensive care unit were categorized in the severe group.
RESULTS: A total of 1213 COVID-19-positive patients and 1034 COVID-19-negative patients were included in the study. The IGLR, NLR, PLR, CRP, CAR, and ferritin levels were significantly higher, and the leukocyte, IG, neutrophil, lymphocyte, monocyte, basophil, and eosinophil levels were significantly lower in the COVID-19-positive group than the COVID-19-negative group (p<0.05 for all). The severe group had higher median IG, IGLR, neutrophil, NLR, PLR levels than the mild, moderate, and COVID-19-negative groups (p<0.05 for all). Receiver operating characteristic analysis revealed an area under the curve value for IGLR, CAR, CRP, IG, NLR, and ferritin of 0.868, 0.860, 0.834, 0.848, 0.845, 0.841, and 0.827, respectively, which differentiated severe COVID-19 patients from mild and moderate COVID-19 patients.
DISCUSSION AND CONCLUSION: The results suggest that the IGLR may be useful to distinguish severe COVID-19 patients at the time of admission. Further exploration is warranted to fully determine the potential value of the IGLR in disease monitoring.