5. Covariate analyses for colour duplex ultrasound and contrast‐enhance colour duplex ultrasound studies (based on individual participants data).
| CDUS studies (n = 16) | CE‐CDUS studies (n = 11) | ||||
| Covariates |
Summary sensitivity % (95% CI) |
Summary specificity % (95% CI) |
Covariates |
Summary sensitivity % (95% CI) |
Summary specificity % (95% CI) |
| Age | Age | ||||
| < 72 years (6 studies) | 80 (50 to 95) | 94 (89 to 97) | < 72 years (4 studies) | 96 (87 to 99) | 96 (84 to 98) |
| ≥ 72 years (10 studies) | 86 (63 to 95) | 90 (81 to 95) | ≥ 72 years (7 studies) | 88 (73 to 95) | 94 (87 to 97) |
| P value | 0.65 | 0.25 | P value | 0.07 | 0.76 |
| Gender | Gender | ||||
| Men < 95 (7 studies) | 78 (64 to 88) | 90 (82 to 94) | Men < 95 (3 studies) | NE | NE |
| Men ≥ 95 (9 studies) | 91 (59 to 99) | 94 (85 to 98) | Men ≥ 95 (8 studies) | 92 (76 to 98) | 93 (89 to 96) |
| P value | 0.59 | 0.43 | P value | NE | NE |
| Study design (direction) | Study design (direction) | ||||
| Prospective (7 studies) | 68 (50 to 83) | 92 (82 to 96) | Prospective (7 studies) | 95 (83 to 99) | 94 (86 to 98) |
| Retrospective/unclear (9 studies) | 92 (73 to 98) | 91 (84 to 96) | Retrospective/unclear (4 studies) | 92 (74 to 98) | 96 (90 to 99) |
| P value | 0.09 | 0.99 | P value | 0.76 | 0.74 |
| Publication year | Publication year | ||||
| Before 2006 (8 studies) | 96 (87 to 99) | 94 (84 to 98) | Before 2006 (2 studies) | NE | NE |
| After 2005 (8 studies) | 58 (43 to 71) | 90 (83 to 94) | After 2005 (9 studies) | 94 (82 to 98) | 96 (89 to 99) |
| P value | < 0.001 | 0.42 | P value | NE | NE |
| Number of US operators | Number of US operators | ||||
| 1 operator (4 studies) | 71 (30 to 94) | 91 (87 to 94) | 1 operator (2 studies) | NE | NE |
| > 1 operators (8 studies) | 76 (60 to 87) | 92 (83 to 97) | > 1 operators (6 studies) | 95 (82 to 99) | 96 (84 to 99) |
| P value | 1 | 1 | P value | NE | NE |
| Country | Country | ||||
| Americas (4 studies) | 99 (03 to 99) | 91 (71 to 98) | Americas (2 studies) | NE | NE |
| Europe (12 studies) | 78 (61 to 89) | 92 (87 to 96) | Europe (9 studies) | 92 (83 to 97) | 97 (91 to 99) |
| P value | 0.85 | 0.88 | P value | NE | NE |
| Sample | Sample | ||||
| < 100 (5 studies) | 88 (67 to 96) | 90 (82 to 95) | < 100 (8 studies) | 96 (83 to 99) | 94 (86 to 98) |
| > 100 (11 studies) | 76 (46 to 92) | 95 (90 to 98) | > 100 (3 studies) | NE | NE |
| P value | 0.42 | 0.19 | P value | NE | NE |
| Quality | Quality | ||||
| High quality (4 studies) | 53 (40 to 66) | 88 (72 to 96) | High quality (5 studies) | 96 (88 to 99) | 97 (78 to 99) |
| Low/unclear quality (12 studies) | 91 (77 to 97) | 93 (87 to 96) | Low/unclear quality (6 studies) | 90 (77 to 96) | 93 (87 to 97) |
| P value | < 0.001 | 0.36 | P value | 0.19 | 0.94 |
CDUS: colour duplex ultrasound; CE‐CDUS: Contrast enhanced ultrasound; n: number of participants; NE: not estimable.