Age-adjusted D-dimer improved specificity (11.8% vs 4.0%) with minimal sensitivity loss (97.5% vs 99.4%) compared to standard thresholds, with similar AUC (0.727 vs 0.734; P=0.41).
Observational (n=979)
No
Does age-adjusted D-dimer improve diagnostic specificity without compromising sensitivity compared to standard D-dimer in older adults with suspected pulmonary embolism?
Age-adjusted D-dimer improves specificity with minimal sensitivity loss for excluding PE in older adults, though near-threshold results warrant careful clinical reassessment.
Absolute Event Rate: 0.727% vs 0.734%
p-value: p=0.41
Background Age‐adjusted D‐dimer (AAD) thresholds are used to reduce false positives in older patients evaluated for pulmonary embolism (PE). However, evidence is limited regarding test behavior near the individualized cutoff (“near‐threshold” zone) and the safety of excluding PE in AAD‐negative cases. Methods We conducted a retrospective diagnostic accuracy study of adults ≥ 50 years presenting to a tertiary emergency department (2015–2019) with suspected PE who underwent D‐dimer testing and definitive imaging (CT pulmonary angiography or V/Q scintigraphy). Diagnostic performance of the standard threshold (0.5 µg/mL, FEU) and AAD (age × 0.01 µg/mL) was assessed using ROC analysis. Accuracy metrics are reported with 95% confidence intervals (CIs) via bootstrap; AUC CIs and between‐curve comparisons used the DeLong method. The near‐threshold zone was defined as ±0.1 µg/mL around the AAD cutoff. Clinical charts of AAD‐negative PE cases were reviewed. Results Among 979 patients, 162 (16.5%) had imaging‐confirmed PE. Standard D‐dimer showed sensitivity 99.4% (95% CI 98.0–100.0) and specificity 4.0% (2.7–5.4); AAD showed sensitivity 97.5% (94.8–99.4) and specificity 11.8% (9.6–13.9). AUCs were 0.734 and 0.727, with no significant difference (DeLong p = 0.41). Within the near‐threshold window, PE prevalence was 7.7%, increasing with age (28.6% in ≥ 80 years). Three patients had PE despite AAD‐negative results; all had segmental or subsegmental emboli, and no in‐hospital complications were documented in the available records. Conclusion In this imaging‐selected retrospective cohort, AAD improved specificity with minimal sensitivity loss. However, AAD should not be used as a stand‐alone rule‐out strategy and should be applied only within clinical probability‐guided diagnostic pathways. Near‐threshold results are not risk‐free, particularly in older adults, and should prompt careful clinical reassessment when overall probability remains concerning.
Yıldırım et al. (Thu,) conducted a observational in Suspected pulmonary embolism (n=979). Age-adjusted D-dimer (AAD) vs. Standard D-dimer threshold (0.5 µg/mL) was evaluated on Area under the ROC curve (AUC) for diagnosing pulmonary embolism (p=0.41). Age-adjusted D-dimer improved specificity (11.8% vs 4.0%) with minimal sensitivity loss (97.5% vs 99.4%) compared to standard thresholds, with similar AUC (0.727 vs 0.734; P=0.41).