Table 6.
Hypoxaemia prevalence, sensitivity, specificity, positive likelihood ratio (LR+) and negative likelihood ratio (LR-) for combinations of clinical signs among children in 12 secondary-level hospitals in southwest Nigeria (Mar 2016-Mar 2017).
| Model | Population | N (%) | AUC | Sensitivity | Specificity | LR+ | LR– |
|---|---|---|---|---|---|---|---|
| Model 1 (WHO) | Overall | 6017 (32.0) | 0.646 | 57% | 72% | 2.05 | 0.596 |
| - Neonate | 2292 (37.3) | 0.675 | 65% | 71% | 2.2 | 0.503 | |
| - Infant | 1220 (35.1) | 0.659 | 62% | 70% | 2.05 | 0.546 | |
| - Young child | 1785 (29.2) | 0.574 | 43% | 72% | 1.53 | 0.795 | |
| - Older child | 701 (22.9) | 0.553 | 33% | 78% | 1.48 | 0.865 | |
| - ALRI | 1011 (58.2) | 0.610 | 74% | 48% | 1.42 | 0.541 | |
| - AFE | 912 (34.2) | 0.579 | 48% | 68% | 1.5 | 0.768 | |
| - Malaria | 1502 (29.8) | 0.581 | 45% | 72% | 1.6 | 0.774 | |
| - Preterm | 644 (42.9) | 0.632 | 63% | 64% | 1.73 | 0.587 | |
| - Neonatal encephalopathy | 1281 (40.1) | 0.672 | 67% | 67% | 2.05 | 0.488 | |
| - Neonatal sepsis | 1190 (48.5) | 0.615 | 64% | 59% | 1.56 | 0.613 | |
| Model 2 | Overall | 7132 (37.9) | 0.656 | 65% | 67% | 1.93 | 0.532 |
| - Neonate | 2292 (37.3) | 0.675 | 65% | 71% | 2.2 | 0.503 | |
| - Infant | 1466 (42.2) | 0.677 | 72% | 63% | 1.96 | 0.442 | |
| - Young child | 2265 (37.0) | 0.628 | 60% | 65% | 1.74 | 0.608 | |
| - Older child | 1090 (35.7) | 0.614 | 57% | 66% | 1.67 | 0.655 | |
| - ALRI | 1388 (80.0) | 0.581 | 92% | 25% | 1.21 | 0.343 | |
| - AFE | 1191 (44.6) | 0.612 | 64% | 59% | 1.55 | 1.42 | |
| - Malaria | 1964 (39.0) | 0.626 | 62% | 63% | 1.69 | 0.6 | |
| - Preterm | 644 (42.9) | 0.632 | 63% | 64% | 1.73 | 0.587 | |
| - Neonatal encephalopathy | 1281 (40.1) | 0.672 | 67% | 67% | 2.05 | 0.488 | |
| - Neonatal sepsis | 1190 (48.5) | 0.615 | 64% | 59% | 1.56 | 0.613 | |
| Model 3 | Overall | 8162 (43.4) | 0.655 | 70% | 61% | 1.8 | 0.494 |
| - Neonate | 2326 (37.9) | 0.491 | 66% | 70% | 2.19 | 0.491 | |
| - Infant | 1650 (47.5) | 0.675 | 77% | 58% | 1.83 | 0.397 | |
| - Young child | 2824 (46.1) | 0.653 | 74% | 57% | 1.71 | 0.458 | |
| - Older child | 1341 (43.9) | 0.628 | 68% | 58% | 1.61 | 0.557 | |
| - ALRI | 1423 (82.0) | 0.575 | 93% | 22% | 1.19 | 1.15 | |
| - AFE | 2027 (75.9) | 0.574 | 88% | 26% | 1.2 | 0.442 | |
| - Malaria | 2408 (47.8) | 0.637 | 73% | 55% | 1.6 | 0.497 | |
| - Preterm | 652 (43.5) | 0.635 | 64% | 64% | 1.74 | 0.574 | |
| - Neonatal encephalopathy | 1295 (40.5) | 0.676 | 68% | 67% | 2.06 | 0.475 | |
| - Neonatal sepsis | 1205 (49.1) | 0.616 | 65% | 59% | 1.56 | 0.604 | |
| Model 4 | Overall | 9573 (50.9) | 0.653 | 77% | 54% | 1.66 | 0.429 |
| - Neonate | 2948 (48.0) | 0.669 | 74% | 60% | 1.84 | 0.431 | |
| - Infant | 2035 (58.5) | 0.657 | 85% | 46% | 1.59 | 0.322 | |
| - Young child | 3189 (52.1) | 0.646 | 79% | 51% | 1.59 | 0.421 | |
| - Older child | 1370 (44.8) | 0.633 | 70% | 57% | 1.62 | 1.47 | |
| - ALRI | 1501 (86.5) | 0.560 | 95% | 17% | 1.14 | 0.293 | |
| - AFE | 2128 (79.7) | 0.568 | 91% | 22% | 1.18 | 0.39 | |
| - Malaria | 2756 (54.7) | 0.637 | 80% | 48% | 1.52 | 0.422 | |
| - Preterm | 816 (54.4) | 0.635 | 74% | 53% | 1.57 | 0.487 | |
| - Neonatal encephalopathy | 1646 (51.5) | 0.651 | 75% | 55% | 1.67 | 0.448 | |
| - Neonatal sepsis | 1406 (57.2) | 0.620 | 73% | 51% | 1.49 | 0.528 |
Model 1 (WHO) = Respiratory rate ≥70 breaths per minute (bpm), Central cyanosis, Severe respiratory distress (any of: severe chest wall in-drawing, grunting, gasping, tracheal tug, head nodding), Inability to feed.
Model 2 = Model 1 with age-specific tachypnoea (Neonate ≥70 bpm; Infant ≥60 bpm; Young child ≥50 bpm; Older child ≥40 bpm).
Model 3 = Model 2 plus Decreased conscious state (unconscious/difficult to rouse/confused).
Model 4 = Model 3 plus Heart rate ≥160 beats per minute.
ALRI = acute lower respiratory infection; AFE = acute febrile encephalopathy; AUC = the area under the ROC curve; LR+ positive likelihood ratio (LR+ = sensitivity/(1-specificity)); LR- negative likelihood ratio (LR- = specificity/(1-sensitivity)). A positive LR >10 and a negative LR <0.1 are considered to exert highly significant changes in probability, such as to alter clinical management.