Comorbidities and prognostic performance of D-Dimer in acute pulmonary embolism elderly patients

Background Risk stratification remains a critical point in patients with acute pulmonary embolism (PE). A role of D-dimer in risk assessment has been suggested in these patients, but its prognostic accuracy may be hampered by comorbidities, which are frequent in the elderly. The present study was aimed to investigated the impact of comorbidity assessment on the prognostic ability of Ddimer to predict 90-day mortality in hemodynamically stable elderly patients with acute PE. 2 Methods All consecutive hemodynamically stable patients aged >65 years old evaluated in the Emergency Department of Vimercate Hospital for clinically suspected PE since 2010 through 2014, were included in this retrospective cohort study. Pulmonary embolism was ruled out or confirmed performing a pulmonary computerized tomography angiography. Ddimer was measured and simplified Pulmonary Embolism Severity Index (sPESI) score and Charlson Comorbidity Index (CCI) score values were recorded. 3 Results Study population was represented by 162 patients. The overall mortality at 90 days was 19.8%. Baseline clinical characteristics of the study population are shown in Table 1. Table 2 shows the effect of different variables on mortality at 90 days. The difference between survival curves for low (CCI<1) and high (CCI>1) comorbidity burden patients was statistically significant (HR=4.484, p-value<0.001), Figure 1. For mortality at 90 days, HR of D-dimer was 7.74 (p-value=0.049) for patients with low and 2.68 (p-value=0.042) for patients with high comorbidity burden. When both D-dimer and sPESI were included into the model, the AUC increased in patients with low comorbidity burden, with a ½NRI = 0.424 (p-value=0.025), whereas the increment in AUC in patients with high comorbidity burden was smaller and the corresponding ½NRI was not statistically significant (p-value=0.165), Figure 2. 4 Conclusions Higher values of D-dimer, sPESI score and CCI score were associated with an increased HR for death at 90 days. D-dimer increased significantly the ability of sPESI for predicting 90-day mortality in patients with low comorbidity burden, but not in patients with high comorbidity burden. These results suggest that, in hemodynamically stable elderly patients with acute PE, comorbidities condition significantly the prognostic performance of D-dimer, which have a modest prognostic performance in patients with a high comorbidity burden, but appears to be a good predictor of death in subjects with low comorbidity burden.