Neutrophil-to-Lymphocyte Ratio and Platelet-to-Lymphocyte Ratio as Predictive Markers for DVT

Abstract

SESSION TITLE: Diagnosis and Evaluation of Venous Thromboembolism SESSION TYPE: Original Investigation Slide PRESENTED ON: Wednesday, November 1, 2017 at 08:45 AM - 10:00 AM PURPOSE: To check whether neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) have a role in determining whether or not a patient has DVT. And if so, how do they compare to our current test of choice (D-Dimer). METHODS: A retrospective chart review of 700 patients that presented with lower extremity swelling was conducted. Patients who had a diagnosis of DVT confirmed via ultrasound Doppler were analyzed (DVT group) and compared to patients who had a negative ultrasound Doppler for DVT (Control group). Patients who qualified for the study (met inclusion and exclusion criteria) had their NLR and PLR calculated based on a CBC done on the same day of the Doppler study. Cut off values from prior studies were used to determine if the NLR and PLR were positive or negative for each qualified patient (those values were revalidates using a receiver operating characteristic curve(ROC)). A positive NLR was defined as a result of 3.4 and above, whereas a negative NLR was defined as a result below 3.4. A positive PLR was defined as a result of 260 and above, whereas a negative PLR was defined as result below 260. D-dimer was also assessed on our selected patients. A positive D-Dimer defines as a result of 500ng/dl and above, whereas a negative D-dimer was defined as below 500ng/dl. An additional group was analyzed called the “double positive” which is when both the NLR and PLR are positive whereas a double negative result is when both NLR and PLR are negative. SPSS v. 24.0. was used to determine the specificity, sensitivity, positive predictive value (PPV) and negative predictive value (NPV) of NLR, PLR, D-dimer and “double positive” groups in patients with and without DVT. RESULTS: The sensitivity of NLR is 90.2%, specificity is 80.4%, PPV 82.1% and NPV 89.1%. The sensitivity of PLR is 62.75%, specificity 98.0%, PPV 97.0% and NPV 72.5%. The sensitivity of “Double positive” yielded a sensitivity of 100%, specificity 100%, PPV 100% and NPV 100%. On the other hand, the sensitivity of D-Dimer is 88.2%, specificity 35.3%, PPV 57.7%, NPV 75.0%. All analysis where statistically significant with p-values <0.001%. The results did not differ significantly when variables such as race, gender or smoking status were taken into account. However, the sensitivity and specificity of those tests were slightly higher in recurrent DVT when compared to new DVT. CONCLUSIONS: Based on this study, both NLR and PLR are better predictors of the presence or absence of DVT compared to D-Dimer. NLR can be useful to rule-out DVT when it is negative. Whereas PLR can be useful in ruling-in DVT when its positive. Furthermore, combining a positive NLR and positive PLR yielded the best prognostic value of the presence of DVT. CLINICAL IMPLICATIONS: NLR and PLR ratios offer a new powerful, affordable, simple and readily available tool in the hands of clinicians to help them in the diagnosis of DVT. DISCLOSURE: The following authors have nothing to disclose: Jason Mouabbi, Rami Zein, Szpunar Susanna, Louis Saravolatz, Zyad Kafri, Tarik Hadid No Product/Research Disclosure Information