Comorbidity burden conditions the prognostic performance of D-dimer in elderly patients with acute pulmonary embolism

The prognostic accuracy of D-dimer for risk assessment in acute Pulmonary Embolism (APE) patients may be hampered by comorbidities. We investigated the impact of comorbidity burden (CB) by using the Charlson Comorbidity Index (CCI), on the prognostic ability of D-dimer to predict 30 and 90-day mortality in hemodynamically stable elderly patients with APE. All patients aged >65 years with normotensive APE, consecutively evaluated in the Emergency Department since 2010 through 2014 were included in this retrospective cohort study. Area under the curve (AUC) and ½ Net Reclassification Improvement (NRI) were calculated. Study population: 162 patients, median age: 79.2 years. The optimal cut-off value of CCI score for predicting mortality was ≤1 (Low CB) and >1 (High CB), AUC = 0.786. Higher levels of D-dimer were associated with an increased risk death at 30 (HR = 1.039, 95%CI:1.000–1.080, p = 0.049) and 90 days (HR = 1.039, 95%CI:1.009–1.070, p = 0.012). When added to simplified Pulmonary Embolism Severity Index (sPESI) score, D-dimer increased significantly the AUC for predicting 30-day mortality in Low CB (AUC = 0.778, 95%CI:0.620–0.937, ½NRI = 0.535, p = 0.015), but not in High CB patients (AUC = 0.634, 95%CI:0.460–0.807, ½ NRI = 0.248, p = 0.294). Similarly, for 90-day mortality D-dimer increased significantly the AUC in Low CB (AUC = 0.786, 95%CI:0.643–0.929, ½NRI = 0.424, p-value = 0.025), but not in High CB patients (AUC = 0.659, 95%CI:0.541–0.778, ½NRI = 0.354, p-value = 0.165). In elderly patients with normotensive APE, comorbidities condition the prognostic performance of D-dimer, which was found to be a better predictor of death in subjects with low CB. These results support multimarker strategies for risk assessment in this population.