Table 4:
Validity of DPC data for identifying hyponatremia based on various cutoff values and the timing of the registered diagnosis.
| Timing | Cutoff, mmol/l | Disease frequency based on sodium data (%) | Diagnosis frequency based on DPC data (%) | Sensitivity (%) | Specificity (%) | PPV (%) | NPV (%) | LR+ | LR− | DOR |
|---|---|---|---|---|---|---|---|---|---|---|
| During | <135 | 23.1 | 1.0 | 4.1 | 99.9 | 92.5 | 77.6 | 41.1 | 0.96 | 42.8 |
| hospitalization | <130 | 6.9 | 1.0 | 11.4 | 99.8 | 77.9 | 93.8 | 47.2 | 0.89 | 53.1 |
| (N = 1 813 356) | <125 | 2.1 | 1.0 | 23.8 | 99.5 | 50.4 | 98.3 | 46.3 | 0.77 | 60.4 |
| On admission day | <135 | 14.9 | 0.9 | 5.4 | 99.9 | 90.1 | 85.8 | 51.9 | 0.95 | 54.8 |
| (N = 1 351 760) | <130 | 4.2 | 0.9 | 16.4 | 99.8 | 76.9 | 96.5 | 76.3 | 0.84 | 91.0 |
| <125 | 1.4 | 0.9 | 33.9 | 99.6 | 52.1 | 99.1 | 78.1 | 0.66 | 118.0 | |
| After admission day | <135 | 22.2 | 0.3 | 1.3 | >99.9 | 88.3 | 78.0 | 26.5 | 0.99 | 26.9 |
| (N = 1 504 321) | <130 | 6.4 | 0.3 | 3.2 | 99.9 | 64.5 | 93.7 | 26.4 | 0.97 | 27.2 |
| <125 | 1.9 | 0.3 | 5.5 | 99.8 | 32.0 | 98.2 | 24.8 | 0.95 | 26.2 |
DPC, Diagnosis Procedure Combination; NPV, negative predictive value; PPV, positive predictive value; LR+: positive likelihood ratio; LR−: negative likelihood ratio; DOR: diagnostic odds ratio