key: cord-0755059-heqjwo98
authors: Erdogan, Arife; Can, Fatma Ezgi; Gönüllü, Hayriye
title: Evaluation of the prognostic role of NLR, LMR, PLR, and LCR ratio in COVID‐19 patients
date: 2021-05-28
journal: J Med Virol
DOI: 10.1002/jmv.27097
sha: b96e566a8e094b9c531ecb255684db32fcdabb01
doc_id: 755059
cord_uid: heqjwo98

We aimed to find the most useful biomarker by examining the prognostic effect of neutrophil‐lymphocyte ratio (NLR), lymphocyte‐monocyte ratio (LMR), platelet‐lymphocyte ratio (PLR), and lymphocyte‐C reactive protein ratio (LCR) in patients with coronavirus disease 2019 (COVID‐19). Three hundred and four patients diagnosed with COVID‐19 infection in our hospital within 5 months (April–August 2020) were examined. Laboratory values and demographic findings of the patients were analyzed retrospectively. Thirty‐six patients were diagnosed with severe cases. The ratio of NLR, LMR, PLR, and LCR of patients with severe and those with nonsevere clinical symptoms were statistically analyzed. The NLR and PLR ratios of those with severe clinical symptoms were significantly higher (p < 0.001), the LCR rate was significantly lower (p < 0.001), and there was no significant difference in the LMR rate (p = 0.199). When we examined other peripheral blood parameters, we found that CRP was high, lymphocyte and monocyte were low (p < 0.001), but neutrophil (p = 0.416) and platelet (p = 0.998) were not statistically different between the groups. According to the results, routine blood values are abnormal in patients with COVID‐19. NLR, PLR, and LCR ratios can be used as more significant biomarkers than other values in predicting the prognosis of patients.

reaction (PCR) is the gold standard of COVID-19 diagnosis, common routine and low-cost techniques, such as biochemical and hemogram analysis can be quick and easy tests that facilitate the diagnosis and prognosis of this disease. 7 In inflammation seen in viral pneumonia, such as COVID-19, an imbalance of immune response is seen as a result of severe inflammatory response and poor immune response. 1 As a result, circulating biomarkers that show inflammation, as well as the immune system, can be good indicators of the prognosis of patients with COVID-19. 8 Of these, white blood cell (WBC) count, neutrophil (NEU) to lymphocyte (LYM) ratio (NLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-monocyte ratio (LMR), and serum C-reactive protein (CRP) levels are beneficial for the prognosis of patients with viral pneumonia, and they were investigated as predictors.

In our study, we aimed to discover the most useful diagnostic biomarkers by investigating and comparing the prognostic effects of NLR, LMR, PLR, and lymphocyte-C reactive protein ratio (LCR) in COVID-19 cases.

We performed our research by retrospectively reviewing the archives after receiving the consent of the ethics committee. Patients who were admitted to the emergency room and pandemic outpatient clinics between April 2020 and August 2020 and were positive for the SARS-CoV-2 PCR test were included in the study. The medical records of the patients included in the study were analyzed through the hospital data processing database, and laboratory results, demographic findings, and clinical outcomes were collected from the electronic medical record network.

From the patients, those who had symptoms, such as shortness of breath, fever, cough, sore throat, diarrhea, smell, and taste disturbance were subjected to PCR amplification in case of possible infection. Combined naso-oropharyngeal swabs were taken and analyzed by reverse transcription-polymerase chain reaction in the Central Laboratory of our hospital. For laboratory tests, complete blood count, biochemistry, and CRP values were checked. Patients were divided into two groups with severe clinical and nonsevere clinical outcomes based on the provisional guidance of the WHO (2) and the national COVID-19 diagnostic and treatment guidelines.

Those with nonsevere clinical outcomes were classified as Group 1, and those with severe outcomes as Group 2. Group 1: patients who are discharged or hospitalized. Group 2: patients were intubated, in need of intensive care, or died. Between groups 1 and 2; NLR, LMR, PLR, and LCR were compared. 

In this study, we examined 304 SARS-CoV-2 positive patients. We found that the median age was 45 (33;55). Three hundred and four COVID-19 positive patients were studied. Thirty-six patients had severe and 268 had nonsevere clinical outcomes. Table 1 shows the demographic characteristics of the patients. The average age of the patients with poor clinical outcomes was significantly higher than the other group and had comorbid diseases.

We compared NLR, LMR, PLR, and LCR values in severe and nonsevere patients with COVID-19. In Table 3 we compared routine blood parameters and we found that there was a significant difference in many parameters between the severe group and the nonsevere group. The severe group had a higher CRP level (p < 0.001), but lower hemoglobin concentration (p < 0.001), hematocrit ratio (p < 0.001), lymphocyte ratio (p < 0.001), and monocyte count (p < 0.001).

COVID-19 is a systemic multiorgan damage disease caused by coronavirus 2 (SARS-CoV-2) and its primary target organ is the lung, causing the severe acute respiratory syndrome. In severe cases, it can lead to death by causing acute respiratory distress syndrome. 10 Recent studies have shown that the virus enters alveolar cells by binding to the receptor and activates macrophages, allowing inflammatory factors to be released. 11 As a result, factors and chemokines that use other mononuclear cells are released. This increases immune activation, causing inflammation storm and consequently tissue damage. 3 Based on these, we investigated the immunological properties of peripheral blood and the effect of their ratio on prognosis in patients with COVID-19.

In the study conducted by Xu et al, 12 they found that mononuclear cells, mostly lymphocytes, are dominant in the interstitial area of the lung. This explains the reason for the significant decrease in lymphocyte count. It has been found that patients with COVID-19 have defective hematopoiesis system. 13 NEU is the primary component of the immune system that is activated and migrated. At the same time, it enables the production of a large number of cytokines and effector mediators by interacting with other cells. 13 Supporting all of these, in our study, the lymphocyte levels of the patients with a severe clinical picture were significantly lower. However, on the contrary, there was no significant difference between neutrophil levels.

Another issue that needs to be discussed is the impaired blood coagulation functions in patients. As a result of thrombosis, thrombocyte consumption increases and the number of platelets decreases. 14 Damage and inflammation in kidney tissue causes RBC destruction and anemia by reducing erythrogenesis. 15 When we examined the acute phase protein, CRP, one of the new inflammatory biomarkers synthesized by hepatocytes, we found that it increased more in patients with severe clinical outcomes, similar to the studies conducted. 16 What we understand from the studies conducted is that the deterioration and prognosis of the clinical symptoms in COVID-19

are directly related to the immune system and increased 

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Evaluation of the prognostic role of NLR, LMR, PLR and LCR ratio in COVID-19 patients