Table 2. Validation Data Set Performance for Hyperkalemia From 2 and 4 Leads of the ECG.
| Validation Data Set | Value (95% CI) | |||
|---|---|---|---|---|
| 2-Lead ECGa | 4-Lead ECGb | |||
| Sensitivity = Specificity | High Sensitivityc | Sensitivity = Specificity | High Sensitivity | |
| Minnesota (n = 50 099) | ||||
| AUC | 0.883 (0.873-0.893) | 0.883 (0.873-0.893) | 0.901 (0.892-0.911) | 0.901 (0.892-0.911) |
| Sensitivity, % | 79.9 (77.6-82.0) | 90.2 (88.4-91.7) | 81.3 (79.0-83.4) | 89.3 (87.5-91.0) |
| Specificity, % | 81.3 (80.9-81.6) | 63.2 (62.7-63.6) | 84.2 (83.9-84.5) | 70.0 (69.6-70.4) |
| NPV, % | 99.4 (99.3-99.4) | 99.6 (99.5-99.7) | 99.4 (99.3-99.5) | 99.6 (99.5-99.7) |
| PPV, % | 10.1 (9.5-10.7) | 6.0 (5.7-6.4) | 11.9 (11.2-12.6) | 7.2 (6.8-7.7) |
| Florida (n = 6011) | ||||
| AUC | 0.860 (0.837-0.883) | 0.860 (0.837-0.883) | 0.885 (0.863-0.907) | 0.885 (0.863-0.907) |
| Sensitivity, % | 80.5 (75.4-84.9) | 91.3 (87.4-94.3) | 84.0 (79.2-88.0) | 92.3 (88.6-95.1) |
| Specificity, % | 75.2 (74.0-76.3) | 54.7 (53.4-56.0) | 77.1 (75.8-78.0) | 60.5 (59.2-61.7) |
| NPV, % | 98.7 (98.3-99.0) | 99.2 (98.8-99.5) | 99.0 (98.6-99.2) | 99.4 (99.0-99.6) |
| PPV, % | 14.0 (12.3-15.7) | 9.2 (8.1-10.3) | 15.4 (13.7-17.3) | 10.5 (9.3-11.7) |
| Arizona (n = 5855) | ||||
| AUC | 0.853 (0.830-0.877) | 0.853 (0.830-0.877) | 0.880 (0.860-0.901) | 0.880 (0.860-0.901) |
| Sensitivity, % | 78.1 (72.7-82.9) | 88.9 (84.5-92.4) | 82.6 (77.5-86.9) | 92.6 (88.8-95.4) |
| Specificity, % | 75.3 (74.1-76.4) | 55.0 (53.7-56.3) | 77.0 (75.9-78.1) | 60.3 (59.0-61.6) |
| NPV, % | 98.6 (98.2-98.9) | 99.0 (98.6-99.3) | 98.9 (98.6-99.2) | 99.4 (99.1-99.6) |
| PPV, % | 13.3 (11.6-15.0) | 8.7 (7.7-9.8) | 14.8 (13.0-16.7) | 10.1 (9.0-11.4) |
Abbreviations: AUC, area under the receiver operating characteristic curve; ECG, electrocardiogram; NPV, negative predictive value; PPV, positive predictive value.
a
2-Lead ECG using leads I and II.
b
4-Lead ECG using leads I, II, V3, and V5.
c
Operating point at sensitivity of 90%.