Subsequently, the sensitivity analysis was employed to investigate the source of heterogeneity among the eligible studies. We observed that the pooled result varied dramatically after removing a certain article (Kimberly et al.) with distinct cut off value of D-dimer (Figure 3). Therefore, we deleted it and gained a homogeneous pooled result (14 studies with 2179 cases) with fixed effect model which was more convincing (HR = 2.143, 95% CI = 1.922–2.390, P < 0.001; heterogeneity test: I2: 0%, P: 0.549, Figure 4)