Table 3.
Diagnostic Variable | Study Cohorts | ||||||||
---|---|---|---|---|---|---|---|---|---|
Derivation Cohort | Validation Cohorts | ||||||||
(n=1848) | High Prevalence Cohort (n=1035) | Low Prevalence Cohort (n=447) | |||||||
AORTAs≤1/DDage‐adj | ADD≤1/DD500 | P Value | AORTAs≤1/DDage‐adj | ADD≤1/DD500 | P Value | AORTAs≤1/DDage‐adj | ADD≤1/DD500 | P Value | |
Sensitivity | 99.2% (97%–99.9%) | 98.8% (96.4%–99.7%) | 1.0 | 98.3% (95.7%–99.5%) | 99.1% (96.9%–99.9%) | 0.63 | 100% (92.7%–100%) | 98% (89.3%–99.6%) | 1.0 |
Specificity | 51.9% (49.4%–54.4%) | 57.3% (54.9%–59.8%) | <0.001 | 30% (26.9%–33.4%) | 30.2% (27%–33.5%) | 1.0 | 48.7% (43.8%–53.7%) | 52.8% (47.9%–57.7%) | 0.08 |
LR+ | 2.06 (1.96–2.17) | 2.31 (2.18–2.45) | <0.001 | 1.41 (1.34–1.47) | 1.42 (1.35–1.49) | 0.58 | 1.95 (1.74–2.14) | 2.08 (1.86–2.33) | 0.12 |
LR‐ | 0.02 (0–0.06) | 0.02 (0.01–0.07) | 0.67 | 0.06 (0.02–0.15) | 0.03 (0.01–0.11) | 0.33 | 0 (0–0.12)* | 0.04 (0–0.14) | 0.95 |
95% CI in parentheses. ADD indicates aortic dissection detection; DDage‐adj, age‐adjusted d‐dimer cutoff; and LR, likelihood ratio.
To allow LR comparison, a false‐negative unit was added in the corresponding cell.