Table 2.
Performance of RISK11 and IGRA for prevalent and incident tuberculosis
|
Prevalent tuberculosis (ITT cohort) |
Incident tuberculosis (mITT cohort)* |
|||||
|---|---|---|---|---|---|---|
| RISK11 (60)† | RISK11 (26)† | IGRA | RISK11 (60)† | RISK11 (26)† | IGRA | |
| Risk ratio | 5·13 (2·93 to 9·43) | 7·39 (3·46 to 25·69) | 4·43 (1·93 to 14·18) | 2·61 (1·15 to 5·94) | 2·67 (1·04 to 8·66) | 2·83 (0·95 to 99·79) |
| Biomarker prevalence | 9·2% (9·2 to 9·2) | 25·8% (24·1 to 27·4) | 63·4% (61·3 to 65·4) | 9·0% (9·0 to 9·0) | 25·3% (23·7 to 26·9) | 63·2% (61·1 to 65·3) |
| AUC‡ | 0·77 (0·68 to 0·86) | .. | 0·66 (0·58 to 0·73) | 0·63 (0·47 to 0·80) | .. | 0·67 (0·54 to 0·79) |
| Sensitivity | 34·9% (23·7 to 52·2) | 72·1% (54·5 to 90·2) | 88·7% (77·1 to 96·4) | 25·0% (12·7 to 45·9) | 47·5% (25·9 to 75·0) | 83·2% (61·9 to 100·0) |
| Specificity | 91·0% (90·9 to 91·1) | 74·7% (73·1 to 76·4) | 36·9% (34·9 to 39·0) | 91·1% (91·0 to 91·2) | 74·9% (73·2 to 76·5) | 37·0% (34·9 to 39·1) |
| PPV§ | 4·1% (3·0 to 5·4) | 3·1% (2·0 to 4·3) | 1·5% (1·0 to 2·2) | 1·9% (0·9 to 3·0) | 1·3% (0·6 to 2·1) | 0·9% (0·5 to 1·4) |
| PPV (2% incidence)¶ | .. | .. | .. | 6·7% (3·5 to 11·8) | 4·6% (2·5 to 7·1) | 3·3% (2·5 to 3·9) |
| NPV§ | 99·2% (98·8 to 99·6) | 99·6% (99·2 to 99·9) | 99·7% (99·3 to 99·9) | 99·4% (99·0 to 99·8) | 99·5% (99·1 to 99·9) | 99·7% (99·2 to 100·0) |
| NPV (2% incidence)¶ | .. | .. | .. | 97·9% (97·6 to 98·5) | 98·2% (97·5 to 99·2) | 98·8% (97·4 to 100·0) |
| NNS or NNT‖ | 29·9 (21·8 to 46·6) | 37·8 (25·5 to 65·7) | 83·1 (53·2 to 179·8) | 75·1 (40·4 to 277·5) | 123·8 (47·2 to 834·1) | 168 (−440 to 1059) |
Data are risk ratio (95 %CI), % (95% CI), AUC (95% CI), or NNS or NNT (95% CI). ITT=intention to treat. mITT=modified intention-to-treat. IGRA=interferon γ release assay. AUC=area under the receiver operating characteristic curve. PPV=positive predictive value. NPV=negative predictive value. NNS=number needed to screen. NNT=number needed to treat.
Computed over 15-month prognostic window. Performance of RISK11 and IGRA for incident tuberculosis over 6-month and 12-month prognostic windows is in the appendix (p 16).
RISK11 score threshold at 60% or 26%.
AUC is computed across all score thresholds and value is presented under RISK11 (60).
Computed using the prevalence and incidence rates in the trial population as appropriate.
Computed assuming 2% annual incidence of tuberculosis in the population.
NNS for prevalent tuberculosis; NNT for incident tuberculosis. Performance of RISK11 and IGRA for prevalent and incident tuberculosis based on secondary endpoint (≥1 sample+) is in the appendix (p 15).