Table 2.
Diagnostic performance characteristics of three different algorithms for ICD-10 code N17x using the AKIN staging system for AKI as the reference standard
| Diagnostic coding algorithm | AKIN stage | Diagnostic performance characteristics (95 % CI) |
|---|---|---|
| All diagnoses | AKIN stage 1 or greater | Sn = 28.0 (22.6, 34.0)a |
| Sp = 97.2 (94.6, 98.6) | ||
| PPV = 89.2 (80.1, 94.4) | ||
| NPV = 62.2 (57.7, 66.6) | ||
| LR+ = 10.0 | ||
| AKIN stage 2 or greater | Sn = 42.1 (31.7, 53.3) | |
| Sp = 90.6 (87.6, 93.0) | ||
| PPV = 43.2 (32.6, 54.6) | ||
| NPV = 90.2 (87.1, 92.6) | ||
| LR+ = 4.5 | ||
| AKIN stage 3 | Sn = 40.0 (28.1, 53.2) | |
| Sp = 88.9 (85.8, 91.4) | ||
| PPV = 29.7 (20.5, 40.9) | ||
| NPV = 92.7 (89.9, 94.7) | ||
| LR+ = 3.6 | ||
| Admission diagnosis | AKIN stage 1 or greater | Sn = 20.3 (15.7, 25.9) |
| Sp = 97.9 (95.5, 99.0) | ||
| PPV = 88.9 (77.8, 94.8) | ||
| NPV = 60.0 (55.5, 64.3) | ||
| LR+ = 9.7 | ||
| AKIN stage 2 or greater | Sn = 34.2 (24.5, 45.4) | |
| Sp = 93.8 (91.1, 95.6) | ||
| PPV = 48.2 (35.4, 61.2) | ||
| NPV = 89.4 (86.3, 91.8) | ||
| LR+ = 5.5 | ||
| AKIN stage 3 | Sn = 32.7 (21.8, 45.9) | |
| Sp = 92.3 (89.6, 94.4) | ||
| PPV = 33.3 (22.2, 46.6) | ||
| NPV = 92.1 (89.3, 94.2) | ||
| LR+ = 4.2 | ||
| Main diagnosis/most responsible diagnosis | AKIN stage 1 or greaterb | |
| AKIN stage 2 or greater | Sn = 17.1 (10.3, 27.1) | |
| Sp = 97.3 (95.4, 98.5) | ||
| PPV = 52.0 (33.5, 70.0) | ||
| NPV = 87.4 (84.2, 90.0) | ||
| LR+ = 6.3 | ||
| AKIN stage 3 | Sn = 18.2 (10.2, 30.3) | |
| Sp = 96.8 (94.8, 98.1) | ||
| PPV = 40.0 (23.4, 59.3) | ||
| NPV = 91.0 (88.2, 93.2) | ||
| LR+ = 5.7 |
aUsed the Wilson 95 % confidence interval
bResults suppressed as per ICES privacy regulations due to the presence of small cells
Sn sensitivity, Sp specificity, PPV positive predictive value, NPV negative predictive value, LR+ positive likelihood ratio