Estimation of Thrombocytopenia in Patients of COVID-19 in a Tertiary Care Centre as a Prognostic marker

Abstract

Introduction: Severe COVID-19 can lead to critical illness, with Acute Respiratory Distress (ARDS) and Multi-organ Failure (MOF) as its primary complications, eventually followed by intravascular coagulopathy. Haematological changes are common in patients with COVID-19, which include reduced lymphocyte count and platelet count but normal white blood cell count and prolonged activated partial thromboplastin time. Using a simple test like platelet count for assessing the risk of mortality and early identification of severe cases will help in preventing the life threatening complications in patients of COVID-19. Aims and Objectives: To study trends of thrombocytopenia in patients of COVID-19 and to study the correlation between thrombocytopenia and severity of cases of COVID-19. Materials and Methods: The study was carried out in Central Clinical Laboratory in a tertiary care centre. A total of 138 random subjects who were admitted in the COVID ICU were included after they satisfied the eligibility criteria. The CBCs were analyzed on the Beckmann Coulter automated cell count analyzer with EDTA samples obtained from peripheral venipuncture of the patients. Platelet trends over the three samples were studied. Results: An average of all three platelets counts for the patients revealed an overall decreasing trend in cases of non survivors, whereas an overall upward trend was noted in the survivors. A total of 79 patients showed thrombocytopenia (platelet count less than 1.5 lakhs/mm3), during at least one of the tests.46 (33.33%) of these patients succumbed, whereas 33 (23.9%) patients survived. Decreasing trends or overall decreasing trends (Increasing then decreasing) were observed in larger number of non survivors as compared to survivors. Also increasing or overall increasing trends (decreasing then increasing) were common in the survivors. Discussion: Hematological changes are common in SARS patients. For thrombocytopenia, the possible mechanisms of SARS-CoV associated thrombocytopenia may include, 1. Direct infection of megakaryocytes and platelets potentially, inducing cell apoptosis and growth inhibition and/or 2. Immune damage of megakaryocyte progenitor cells or platelets; In addition, the lung damage in SARS patients may also play a role in inducing thrombocytopenia. Conclusion: In this study, we found that platelet count may be a simple, economic, rapid and commonly available laboratory parameter that could straightforwardly discriminate between COVID patients with and without severe disease, while the study of serial platelets counts as trends could help identifying those with a serious risk of mortality.