Table IV.
Accuracy of resting ankle-brachial index (ABI) in detecting any segment with total occlusion according to duplex ultrasound (DUS) imaging (excluding inconclusive ABI)
| Any segment with 100% occlusion | Sensitivity | Specificity | PPV | NPV | Accuracya | P value for accuracyb |
|---|---|---|---|---|---|---|
| All patients | 82 (77.5–86.6) | 75 (72.5–78.3) | 52 (49.0–55.3) | 93 (91.1–94.5) | 77 (74.7–79.5) | |
| Diabetics | ||||||
| Diabetics only | 80 (72.3–85.9) | 68 (63.2–73.4) | 53 (48.3–57.1) | 88 (84.7–91.4) | 72 (67.7–75.9) | .0003 |
| Nondiabetics only | 85 (78.3–90.6) | 80 (76.1–83.0) | 52 (47.3–56.1) | 95 (93.4–96.9) | 81 (77.7–83.7) | |
| CKD | ||||||
| CKD only | 70 (54.8–83.2) | 78 (69.4–85.1) | 54 (44.7–63.8) | 88 (81.6–91.9) | 76 (68.6–82.3) | .6831 |
| Non-CKD only | 85 (79.4–88.8) | 75 (71.9–78.1) | 52 (48.5–55.2) | 94 (91.9–95.4) | 77 (74.7–79.9) |
CKD, Chronic kidney disease; NPV, negative predictive value; PPV, positive predictive value.
Values are presented as percentages (95% confidence interval).
a
Accuracy = (True positive + True negative)/(True positive + True negative + False positive + False negative).
b
χ2 test.