Relationship between Disease Severity and Blood Cell Ratios in Tuberculosis

INTRODUCTION: The neutrophil/lymphocyte (NLR), platelet/lymphocyte (PLR), and monocyte/lymphocyte (MLR) ratios are markers indicating the severity of inflammation that can be obtained from the complete blood count (CBC). We examined the relationships between these inflammatory markers (C-reactive protein [CRP], NLR, PLR, and MLR) and disease extent, as evidenced by chest radiography, bacterial burden, and hospital mortality, in patients hospitalized with a bacteriologically confirmed pulmonary tuberculosis (TB) diagnosis.
METHODS: The study included 265 patients diagnosed with pulmonary TB without multidrug resistance. CBC and biochemical values were recorded before TB treatment. The disease was defined as mild, moderate, or severe according to the number and location of cavities. The smear grade was used to determine the bacterial burden at the time of diagnosis, and patients were classified into two groups (grade≥3 or <3) depending on the number of bacilli detected in sputum smear microscopy analysis.
RESULTS: A comparison of the NLR (7.32±6.26 vs. 5.14±4.87), PLR (349.61±241.49 vs. 244.52±167.4), and MLR (0.78±0.43 vs. 0.61±0.34) between patients with severe and moderate/mild disease revealed significantly higher values in patients with severe disease (p<0.001). These values were not significantly correlated with the smear grade (p>0.05). Hospital mortality was observed in nine patients (3%), and the NLR and CRP levels had significant relationships with mortality (p<0.05).
DISCUSSION AND CONCLUSION: NLR, PLR, and MLR obtained from the complete blood count, which is a simple and inexpensive method at the time of diagnosis, were found to be associated with the radiological extent of the disease. In addition, these markers may be useful in the early identification of severe disease.

Keywords: Complete blood count, radiology, tuberculosis.