Role of Platelet to Lymphocyte Ratio (PLR) and its Correlation with NIHSS (National Institute of Health Stroke Scale) for Prediction of Severity in Patients of Acute Ischemic Stroke

Abstract

Background and objectives: Stroke is the second leading cause of death and third most common cause of disability-adjusted life years in the world. Atherosclerosis plays a key role in the pathogenesis of stroke and inflammation is central in the initiation, progression and complications of atherosclerosis by mediating every stage of atheroma development. High platelet counts may increase thrombocyte activation and aggravate the release of inflammatory mediators. In contrast, lymphocytes exert anti-inflammatory response in atherosclerosis development. The advantage of platelet to lymphocyte ratio (PLR) is that it reflects the condition of both inflammation and thrombosis pathways and is more valuable than either platelet or lymphocyte counts alone. This emerging marker has not been frequently studied with acute ischemic stroke; hence aim of the present study was to find out the role of PLR (Platelet to lymphocyte ratio) in patients of acute ischemic stroke and correlating with NIHSS for predicting the prognosis.

Material and methods: 100 cases of AIS and equal number of age and gender matched control were enrolled in the study. NIHSS score and PLR (from the CBC test) was calculated both at admission and on day 7 or discharge.

Results: Maximum subjects in our study were in the age range of 61-70 years with males (69%) outnumbering females (31%). Incidence of hypertension, diabetes mellitus, hyperlipidemia, smoking and alcoholism was more in the cases than controls. Mean PLR was higher in the patients of AIS (235.98±93.92) as compared to control group (115.60±27.87) (p=0.0001). Moreover, there was statistically significant, positive correlation between PLR and NIHSS score both at admission and discharge. PLR value increased significantly from the baseline in patients who deteriorated (263.42±108.98 to 346.28±125.35; p=0.016), decreased drastically in patients who improved (242.27±75.14 to 167.19±57.91; p=0.0001) and did not change much in patients who tend to remain static (181.35±105.40 to 183.36±111.61; p=0.955).

Conclusion: Platelet to lymphocyte ratio (PLR) is a simple, cost effective and easily obtainable novel inflammatory marker that may help in predicting the severity of disease and prognosis in terms of functional outcome as evidenced by its increased value in patients of acute ischemic stroke as well as its linear positive correlation with NIHSS score.