A negative D-dimer identifies patients at low risk of death within 30 days: a prospective observational emergency...

To determine the ability of a normal D-dimer level (<0.5 mg/l) to identify emergency department (ED) patients at low risk of 30-day all-cause mortality.

In this prospective observational study, D-dimer levels of adult medical patients were assessed at arrival to the ED. Data on 30-day survival status were extracted from the Danish Civil Registration System with complete follow-up.

The Hospital of South West Jutland.

All patients aged 18 years or older who required any blood sample on a clinical indication on arrival to the ED. Participants were required to give written informed consent before enrollment.

The study population of 1 518 patients with median age 66 years of which 49.4% were female. Of the 791 (52.1%) patients with normal D-dimer levels, 3 (0.4%) died within 30 days; one death resulted from an unrelated traumatic accident. Of the 727 (47.9%) patients with abnormal D-dimer levels (≥0.50 mg/l), 32 (4.4%) died within 30 days. Patients with normal D-dimer levels had a significantly lower 30-day mortality compared to patients with abnormal D-dimer levels (odds ratio 0.08, 95% CI 0.02-0.28): of the 35 patients who died within 30 days, 19 (54.3%) had normal or near normal vital signs when first assessed.

Normal D-dimer levels identified patients at low risk of 30-day mortality. Since most patients who died within 30 days presented with normal or near normal vital signs, D-dimer levels appear to provide additional prognostic information.