D-dimer levels predict COVID-19 severity and mortality.

‐dimer levels predict COVID‐19 severity and mortality 217 outcome was reported in a study as median, range, and interquartile range, we estimated means and SDs using the formula described by Hozo. The random ‐effects model was used for I2 greater than 50%. A P value of less than 0.05 was considered statistically significant. Statis‐ tical testing was 2‐tailed. All the above analyses were presented using RevMan5.4 (The Cochrane Collaboration, Oxford, Copenhagen, Denmark). A total of 23 studies including 3423 patients reported D ‐dimer levels in patients with severe and nonsevere COVID‐19. The pooled analysis showed higher D ‐dimer levels in the severe COVID‐19 group compared with the nonsevere group (mean difference, 1.88; 95% CI, 0.49–3.27; P = 0.008; I2 = 100%; Supplementary material). A higher level of D ‐dimer was also observed in the intensive care unit patients compared with non ‐ICU patients (MD, 1.13; 95% CI, 0.69–1.57; P <0.001; I2 = 97%) and in patients who died as compared with those who survived (MD, 3.54; 95% CI, 2.57–4.52; P <0.001; I2 = 99%; Supple‐ mentary material). The full list of publications included in this meta ‐analysis is presented in the Supplementary material. In conclusion, our analysis showed that ele‐ vated D ‐dimer levels were associated with in‐ creased odds of developing severe disease and increased odds of mortality in patients with COVID‐19.