Table 3.
Diagnostic performance of lipocalin-2 and syndecan-4 biomarkers compared to white blood cell count and C reactive protein at time of enrollment in 110 children hospitalized for radiologically confirmed community-acquired pneumonia to predict infections and severity of disease, and odds ratio and 95 % confidence interval according to the biomarker cut-off with the highest sensitivity and specificity
| Biomarker cut-off value | Sensitivity | Specificity | PPV | NPV | AUC (95 % CI) | OR (95 % CI)*** | |
|---|---|---|---|---|---|---|---|
| S. pneumoniae infection (n = 59) | |||||||
| LIP2 | ≥1,633 | 71.2 % | 62.7 % | 68.9 % | 65.3 % | 0.62 (0.51-0.73) | 4.26 (1.76-10.3) |
| SYN4a | ≤1.78 | 28.8 % | 80.4 % | 63.0 % | 49.4 % | 0.50 (0.39-0.61) | 1.78 (0.62-5.15) |
| WBC | ≥13,500 | 63.8 % | 68.6 % | 69.8 % | 62.5 % | 0.66 (0.55-0.76) | 3.91 (1.50-10.2) |
| CRP | ≥12.3 | 58.6 % | 68.6 % | 68.0 % | 59.3 % | 0.63 (0.52-0.74) | 2.59 (1.03-6.54) |
| Probable bacterial infection (n = 74) | |||||||
| LIP2 | ≥1,633 | 58.1 % | 50.0 % | 70.5 % | 36.7 % | 0.51 (0.40-0.63) | 1.21 (0.49-2.99) |
| SYN44 | ≥7.25 | 31.1 % | 86.1 % | 82.1 % | 37.8 % | 0.54 (0.42-0.65) | 5.54 (1.56-19.7) |
| WBC | ≥10,300 | 74.0 % | 38.9 % | 71.1 % | 42.4 % | 0.57 (0.46-0.69) | 1.90 (0.72-4.97) |
| CRP | ≥7.4 | 64.4 % | 69.4 % | 81.0 % | 49.0 % | 0.65 (0.53-0.76) | 3.35 (1.30-8.63) |
| Probable viral infection (n = 16) | |||||||
| LIP2 | ≥896 | 87.5 % | 28.7 % | 17.3 % | 93.1 % | 0.50 (0.37-0.64) | 3.50 (0.61-20.1) |
| SYN4a | ≤5.64 | 81.2 % | 37.2 % | 18.1 % | 92.1 % | 0.54 (0.40-0.69) | 7.16 (1.20-42.6) |
| WBCa | ≤19,710 | 93.7 % | 28.0 % | 18.3 % | 96.3 % | 0.56 (0.42-0.70) | 8.02 (0.75-85.1) |
| CRPa | ≤5.2 | 75.0 % | 64.5 % | 26.7 % | 93.7 % | 0.67 (0.53-0.80) | 5.95 (1.44-24.7) |
| Severe disease (n = 84) | |||||||
| LIP2 | ≥783 | 83.3 % | 50.0 % | 84.3 % | 48.1 % | 0.64 (0.50-0.78) | 5.45 (1.83-16.2) |
| SYN4a | ≤5.83 | 71.4 % | 50.0 % | 82.2 % | 35.1 % | 0.58 (0.44-0.71) | 4.37 (1.40-13.6) |
| WBC | ≥11,170 | 73.5 % | 69.2 % | 88.4 % | 45.0 % | 0.71 (0.59-0.83) | 8.34 (2.61-26.7) |
| CRP | ≥4.56 | 67.5 % | 61.5 % | 84.8 % | 37.2 % | 0.65 (0.51-0.79) | 2.72 (0.98-7.57) |
95 % CI confidence interval, CRP C reactive protein, LIP2 lipocalin-2, OR odds ratio, SYN4 syndecan-4 (SYN4), WBC white blood cell count
Logistic regression model adjusting for age, sex, study center, ethnicity, parental education, and parental smoking habit
aInverse relationship between biomarker and infection/severity of disease