Table 4.
Comparison of case definitions (CD) for hospitalized respiratory infections (RI) according to their ability to capture pH1N1-positive cases
| Case definition | Cases from entire study period | Cases from study period 1 | |||||
|---|---|---|---|---|---|---|---|
| Sensitivity | Specificity | Area under ROC (95% CI) |
Sensitivity | Specificity | Area under ROC (95% CI) |
||
| Swabbing interval ≤ 4 days | CD4 | 55% | 59% | 0.57 (0.45-0.69) |
56% | 63% | 0.59 (0.42-0.77) |
| CD2 | 95% | 26% | 0.60 (0.54-0.66) |
100% | 44% |
0.72 (0.59-0.84) |
|
| CD3 | 90% | 41% |
0.65 (0.57-0.73) |
94% | 44% | 0.69 (0.55-0.83) |
|
| Swabbing interval ≤ 7 days | CD4 | 55% | 57% | 0.56 (0.45-0.68) |
56% | 59% | 0.57 (0.42-0.73) |
| CD2 | 95% | 22% | 0.59 (0.53-0.64) |
100% | 38% |
0.69 (0.60-0.78) |
|
| CD3 | 90% | 35% |
0.63 (0.55-0.70) |
94% | 41% | 0.68 (0.57-0.79) |
|
Sensitivity, specificity, area under the receiver operator curve (ROC), percentage of pH1N1-positives captured for study period 1 (significant influenza virus circulation in Berlin) and the entire study period (gold standard: PCR confirmation of pH1N1 infections)
*Cases testing negative were only included as pH1N1-negative if the interval from symptom onset to swabbing was ≤ 4 days or ≤ 7 days, respectively. Highest ROC area in bold.