Influenza A (H1N1) and COVID-19 Pneumonias: An Evaluation in the Light of New Hematologic Indices

Objective: Influenza A (H1N1) and COVID-19 viruses are two very different airway viral pneumonia agents that cause similar clinical manifestations and coinfections. The aim of this study was to investigate new laboratory indices, clinical and radiological findings that may help in the differential diagnosis of these two viral pneumonias. Material and Methods: Eighty-nine hospitalized patients, 38 with Influenza A (H1N1) and 51 with COVID-19 pneumonia, were retrospectively analyzed. Laboratory parameters, clinical, and radiological findings of the patients were obtained from their medical files. Numerous hematological and biochemical parameters (neutrophil, monocytes, mean corpuscular volume (MCV), albumin, uric acid, etc) were investigated and new indices (neutrophil/albumin ratio (NAR), lymphocyte-monocyte ratio (LMR), etc) were calculated. Both viral pneumonias were compared in terms of new hematological and biochemical indices and clinical and radiological outcomes. Results: In terms of clinical symptoms, fever, cough, and shortness of breath were higher in influenza A (H1N1) pneumonia, while sore throat, headache, and malaise were higher in COVID-19 pneumonia. Consolidations in influenza A (H1N1) pneumonia and round ground-glass opacities in COVID-19 pneumonia were found as typical radiologic findings. The laboratory parameters most associated with COVID-19 pneumonia were monocytes (OR 27.327, %95 CI: 4.143-180.234, p=0.001), MCV (OR 1.130, %95 CI:1.011-1.262, p=0.031), albumin (OR 0.314, %95 CI:0.111-0.888, p=0.029) and uric acid (OR 1.631, %95 CI:1.055-2.522, p=0.028), and laboratory indices were LMR (OR 0.677, %95 CI:0.492-0.933, p=0.017) and NAR (OR 1.514, %95 CI:1.004-2.282, p=0.048). Conclusion: The most significant laboratory parameters predictive of COVID-19 pneumonia were monocytes, uric acid, albumin, and MCV and the most effective indices were LMR and NAR. Round ground glass opacities were the primary radiological findings suggestive of COVID-19 pneumonia.