Meta-analysis of the statistical performance of the predictive variables for the diagnosis of group A streptococcal pharyngitis in children
| Variables | References | Pop (n) | Se (95% CI) | Sp (95% CI) | PPV (95% CI) | NPV (95% CI) | LR+ (95% CI) | LR− (95% CI) | OR (95% CI) |
|---|---|---|---|---|---|---|---|---|---|
| Positive symptoms | |||||||||
| Tender cervical node | |||||||||
| Node: any size | 22–24 29 30 34 | 3067 | 45 (42 to 48) | 71 (69 to 73) | 40 (37 to 43) | 76 (74 to 77) | 1.6 (1.5 to 1.8) | 0.7 (0.7 to 0.8) | 2.3 (1.9 to 2.8) |
| Node >1.5 cm | 30 | 451 | 81 (73 to 88) | 45 (40 to 50) | 32 (26 to 37) | 89 (83 to 92) | 1.5 (1.3 to 1.7) | 0.4 (0.3 to 0.6) | 3.6 (2.1 to 6.1) |
| Node >2 cm | 27 | 857 | 40 (36 to 45) | 78 (74 to 81) | 63 (57 to 69) | 58 (54 to 62) | 1.8 (1.3 to 2.5) | 0.8 (0.7 to 0.9) | 2.4 (1.8 to 3.2) |
| Pharynx | |||||||||
| Abnormal pharynx | 27 | 857 | 42 (37 to 46) | 77 (72 to 80) | 63 (57 to 68) | 58 (54 to 62) | 1.8 (1.3 to 2.5) | 0.8 (0.6 to 0.9) | 2.3 (1.7 to 3.1) |
| Pharyngeal exudate | 22 29 30 | 1308 | 31 (26 to 36) | 81 (78 to 83) | 37 (32 to 42) | 77 (74 to 79) | 1.6 (1.3 to 1.9) | 0.9 (0.8 to 0.9) | 2.0 (1.5 to 2.6) |
| Swollen tonsils | 22 34 | 1481 | 58 (54 to 63) | 57 (54 to 60) | 39 (35 to 42) | 75 (72 to 78) | 1.3 (1.2 to 1.5) | 0.7 (0.7 to 0.8) | 1.9 (1.5 to 2.3) |
| Fever | |||||||||
| HF | 29 30 | 1006 | 70 (65 to 75) | 32 (29 to 35) | 26 (23 to 30) | 76 (71 to 80) | 1.1 (1.0 to 1.1) | 0.9 (0.7 to 1.1) | 1.2 (0.9 to 1.7) |
| Fever >38°C | 22 27 29 34 | 2789 | 53 (50 to 56) | 56 (54 to 59) | 40 (37 to 43) | 68 (66 to 71) | 1.1 (1.1 to 1.5) | 0.9 (0.8 to 1.1) | 1.3 (1.1 to 2.2) |
| Fever >38.5°C | 23 24 | 576 | 64 (57 to 70) | 28 (24 to 33) | 28 (24 to 32) | 64 (57 to 70) | 0.9 (0.8 to 1.0) | 1.2 (1.0 to 1.6) | 0.7 (0.5 to 1.1) |
| HF or >38°C | 22 27 29 30 34 | 3795 | 56 (54 to 60) | 49 (47 to 51) | 35 (33 to 37) | 70 (67 to 72) | 1.1 (1.1 to 1.3) | 0.9 (0.8 to 1.1) | 1.3 (1.1 to 1.9) |
| Headache | 22–24 27 | 1730 | 51 (48 to 55) | 64 (61 to 67) | 48 (44 to 51) | 67 (64 to 70) | 1.3 (1.1 to 1.5) | 0.9 (0.8 to 1.0) | 1.5 (1.2 to 2.2) |
| Sore throat | 27 34 | 2041 | 86 (83 to 88) | 27 (25 to 30) | 43 (41 to 46) | 75 (71 to 78) | 1.2 (1.1 to 1.2) | 0.5 (0.4 to 0.6) | 2.5 (2.0 to 3.2) |
| Scarlatiniform rash | 22 | 297 | 14 (8 to 23) | 97 (93 to 98) | 63 (41 to 81) | 74 (68 to 79) | 4.7 (2.1 to 10.5) | 0.9 (0.8 to 1.0) | 4.8 (1.8 to 12.7) |
| Petechia on the palate | 22–24 | 873 | 20 (16 to 25) | 88 (86 to 91) | 42 (34 to 51) | 72 (69 to 75) | 1.8 (1.3 to 2.5) | 0.9 (0.9 to 1.0) | 2.0 (1.3 to 2.9) |
| Sudden onset | 23 24 | 576 | 32 (26 to 39) | 69 (65 to 74) | 31 (25 to 38) | 70 (65 to 74) | 1.1 (0.8 to 1.4) | 1.0 (0.9 to 1.1) | 1.1 (0.7 to 1.6) |
| Negative symptoms | |||||||||
| No cough | 23 24 27 29 30 34 | 3627 | 65 (63 to 68) | 55 (53 to 57) | 43 (41 to 45) | 75 (73 to 77) | 1.5 (1.4 to 1.7) | 0.6 (0.6 to 0.7) | 2.4 (2.1 to 3.1) |
| No rhinorrhoea | 22–24 27 30 34 | 3365 | 71 (69 to 74) | 50 (48 to 52) | 43 (41 to 45) | 76 (74 to 79) | 1.3 (1.3 to 1.5) | 0.6 (0.6 to 0.8) | 2.2 (1.9 to 3.3) |
| No abdominal pain | 22–24 | 873 | 69 (64 to 75) | 29 (26 to 33) | 30 (26 to 33) | 69 (64 to 74) | 1.0 (0.9 to 1.1) | 1.1 (0.8 to 1.3) | 1.0 (0.7 to 1.3) |
| No diarrhoea | 23 24 27 | 1433 | 94 (92 to 95) | 12 (10 to 14) | 43 (40 to 45) | 72 (65 to 79) | 1.1 (1.0 to 1.1) | 0.5 (0.3 to 0.7) | 2.3 (1.5 to 3.4) |
| No conjunctivitis | 23 24 | 576 | 100 (NC to 100) | 6 (4 to 8) | 32 (28 to 36) | 100 (NC to 100) | 1.0 (1.0 to 1.0) | NC | NC |
| No viral exanthema | 23 24 | 576 | 88 (83 to 92) | 2 (1 to 3) | 28 (25 to 32) | 22 (11 to 38) | 1.0 (1.0 to 1.0) | 8.4 (3.2 to 21.6) | 0.1 (0.0 to 0.3) |
PPV and NPV should be interpreted with the prevalence of the disease in each study, available in table 1.
HF, history of fever; LR+, positive likelihood ratio; LR−, negative likelihood ratio; n, number of children; NC, not calculable; NPV, negative predictive value; Pop, population; PPV, positive predictive value; Se, sensitivity; Sp, specificity.