Study of Early Warning Efficiency of Different Laboratory Markers in Predicting Progression of Disease in COVID-19

Introduction: COVID 19 pandemic has given rise to several challenges to clinicians and one of the keys in this is to predict the set of patients who progress from mild disease to moderate and severe. Apart from the symptomatology and signs, there are several lab parameters varying from biochemical, hematological to radiological parameters which help us in stratifying the stage of disease and also in deciding on which set of patients need close and vigilant monitoring. This would help us in better stratification of disease and utilize the available infrastructure and resources in an optimum way for better management of the disease. Aim: To analyze the early warning efficiency of laboratory parameters individually or in combination in predicting the progress of disease in patients from mild to moderate/severe disease. Materials and Methods: This was taken up as a retrospective study with 100 cases and 100 controls. The demographic details, inflammatory markers, biochemical markers and hematological markers were analyzed. Test of significance was employed to compare categorical variables while student t-test was employed to test the difference in the mean value such as age between case and control (Mann-Whitney U-test in parameters not having normal distribution). Receiver operating characteristic (ROC) curve was constructed for these parameters using cases and controls and area under the curve (AUC) were estimated which was used as an indicator of sensitivity and specificity of the parameter in their early warning efficiency. The critical values for each of the parameters either individually or in combination was estimated as well. Results: Among the parameters C reactive protein (CRP), d-dimers and eosinopenia have the best early warning efficiency. The area under the ROCs curve for neutrophil lymphocyte ratio (NLR), CRP. Ferritin, lactate dehydrogenase, Eosinopenia was 0.609, 0.947, 0.614, 0.554, 0.617 respectively at triage. However, a combination of eosinopenia with CRP (AUC-0.732) or NLR with CRP (AUC-0.728) have a good sensitivity and specificity in predicting the outcome regarding the progression of the disease. Conclusions: Among the parameters, CRP, d-dimers, Eosinopenia and NLR have the best early warning efficiency. However, a combination of Eosinopenia and CRP at triage should also serve as a red flag sign in patients apart from the well-known NLR and IL6 values.