D-Dimer Levels and Their Impact on Predicting COVID-19 Disease Progression: A Retrospective Study at Diagnostic Laboratory, Zimbabwe from December 2019–December 2020

Abstract

The COVID-19 pandemic, caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), is frequently associated with a hypercoagulable state often reflected by elevated D-dimer levels. This retrospective observational cohort study aimed to evaluate the prognostic utility of D-dimer levels upon patient presentation for predicting subsequent COVID-19 disease progression and overall patient outcomes in a Zimbabwean healthcare context. The study analyzed existing medical records of COVID-19 positive patients tested at the Diagnostic Laboratory Services (DLS) in Bulawayo, Zimbabwe, between December 2019 and December 2020.Data collected included demographic information, D-dimer values, and COVID-19 disease progression, with patients stratified by ward (Casualty, Isolation, High Dependency Unit, and Intensive Care Unit ) to assess severity.Results showed a clear correlation between elevated D-dimer values and increased disease severity. A Receiver Operating Characteristic (ROC) curve analysis was used for predicting severe disease yielded a strong Area Under the Curve (AUC) of 0.881. The optimal D-dimer cutoff value to predict severe COVID-19 was found to be 1.12 μg/mL. Using this cutoff would correctly capture 82% of severe patients (sensitivity). A logistic regression further confirmed D-dimer as a strong predictor, showing that higher D-dimer values were associated with a sharply increased probability of severe disease. In conclusion, this study demonstrates that D dimer is a valuable, readily accessible biomarker for rapid risk stratification. This early, effective stratification can facilitate the timely implementation of intensified monitoring, appropriate anti coagulation strategies, and ultimately contributing to improved clinical outcomes and survival rates within the Zimbabwe healthcare system.