A new viral pneumonia was first detected in Wuhan, China, and was found to be caused by a novel coronavirus, later identified as severe acute respiratory syndrome coronavirus 2 (SARSCoV2), that has since then caused a pandemic. Previous reports have shown that certain laboratory parameters correlated with disease severity and mortality in SARSCoV2 infection.1 The levels of Ddimer, an important prognostic factor, were found to be higher in patients with a clinically severe case of SARSCoV2 than in non-severe cases. A better understanding of this prognostic factor can help physicians predict the disease severity and need for intensive care unit (ICU) care in patients infected with SARSCoV2. This metaanalysis aimed to determine the relationship of Ddimer with disease severity and mortality in SARSCoV2 patients.
There were 29 studies (4.328 patients) included in this metaanalysis. The result showed that increasing Ddimer levels on admission were significantly associated with increased disease severity and mortality. The results obtained were similar to the results reported previously in two other systematic reviews. Analysis by Shah et al demonstrated that patients who had Ddimer levels more than 0.5 mg/L had a twofold higher risk of developing a severe case of the disease and fourfold higher risk of mortality than those who had Ddimer levels less than 0.5 mg/L. Higher cutoff value of Ddimer (>2 mg/L) was considered to be even better in predicting inhospital mortality in SARSCoV2 with a sensitivity of 92.3% and a specificity of 83.3% after adjusting for age, gender, and comorbidities.
Our study also showed that patients with a need for ICU care had nonsignificant higher Ddimer values on admission than patients who did not need ICU care. An earlier study demonstrated that there was an increased incidence of thrombotic complications in patients treated in the ICU. Hypercoagulability state was also found in patients admitted to ICU where Ddimer levels were drastically increased. At the late stages of SARSCoV2, levels of fibrinrelated markers (Ddimer and fibrin degradation product) were either moderately or markedly elevated in all cases of death suggesting a common coagulation activation and secondary hyperfibrinolysis condition in these patients.
Histopathology studies on the lung biopsy of critical patients with SARSCoV2 revealed the presence of occlusion and microthrombosis formation in pulmonary small vessels. The exact mechanism responsible for coagulopathy in SARSCoV2 patients is not yet identified. Whether SARSCoV2 can directly attack vascular endothelial cells expressing high levels of angiotensinconverting enzyme 2 (ACE2) leading to abnormal coagulation and sepsis is an aspect that still needs to be explored.
Our metaanalysis suggests that elevated Ddimer levels can be a marker of poor prognosis in patients with coronavirus disease (COVID19). During a pandemic, risk stratification in triage is necessary, and Ddimer can be one of the potential indicators in the case of highrisk patients. However, only the presence of elevated Ddimer only is not a reason enough to start the administration of therapeutic anticoagulants.
Author: Johanes Nugroho
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