Can NLR, PLR and LMR be used as prognostic indicators in patients with pulmonary embolism? A commentary

Abstract

We read with great interest the article “Prognostic role of NLR, PLR, and LMR in patients with pulmonary embolism” by Köse et al.[1]. They found that the neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), and lymphocyte-monocyte ratio (LMR) were related to the prognosis and clinical severity of patients with pulmonary embolism (PE). First of all, we congratulate the authors for their invaluable contribution to literature. However, we think that there are some points that should be discussed regarding the use of these laboratory parameters.
 White blood cell subtypes NLR, PLR, and LMR have been associated with many inflammatory diseases, including PE [2,3]. These parameters, which can be easily determined by simple and easy measurement of systemic inflammation, maintain their importance today. However, these parameters are affected by many factors such as trauma, local or systemic infection, acute coronary syndromes, and malignancy [3-5]. For these reasons, it would be better for the authors to mention these factors and exclude them from the tables that included malignancy and trauma patients in the study.
 It is known that drugs including steroids can increase neutrophils and decrease lymphocytes and therefore affect NLR, PLR and LMR values [6]. Therefore, it will be more valuable to exclude patients who use drugs that may affect laboratory parameters. In addition, plasma inflammatory biomarkers are time dependent variables, the time of sample collection and the time from the onset of the symptom to the sampling may have an impact on the parameters [3-6]. Therefore, it is important to identify the time from first symptom to sample collection and the factors that may affect it. In conclusion, because NLR, PLR and LMR can be affected by many factors, prospective studies with large populations are needed to show the accuracy of use in critically ill patients.

Systemic inflammatory response index (SIRI) and Systemic immune-inflammation index (SII) to show Thrombus Localization in Patients with Acute Pulmonary Embolism

“…Since it is a lifethreatening disease, early detection of thrombus that may occur in the main branches with non-invasive easily accessible markers will accelerate the diagnosis and treatment processes (11). Studies have shown the relationship between inflammatory markers such as d-dimer and NLR and thrombus localization (4,12). However, the relationship between SIRI or SII and thrombus in patients with PE has not been demonstrated in the literature.…”

“…Some of these markers are d-dimer, neutrophil-lymphocyte ratio (NLR), platelet lymphocyte ratio (PLR), and lymphocyte monocyte ratio (LMR). However, the superiority of these markers over each other has not been documented (4,5).…”

Prognostic Value of Routine Biomarkers in the Early Stage of COVID-19

“…Furthermore, macrolide antibiotics were also prescribed to COVID-19 patients and their anti-inflammatory and immunomodulatory effects are well documented and could interfere with the interpretation of the results [23,24]. A commentary by Bedel et al also highlights the importance of the relative timing between blood sampling and disease onset, especially considering the potential impact that the various drugs taken during this time period can have on NLR, PLR and LMR values [25]. Regardless of its limitations, it was recommended that SARS-CoV-2-positive patients with NLR >6.11 should be started on corticosteroid therapy, which reflects the amount of importance given to this biomarker during the pandemic [26].…”