Table 2.
Subgroup analyses of the eligible studies for the pooled sensitivity, specificity, and DOR based on various exclusion criteria.
| Pooled sensitivity (95%CI), I2 | Pooled specificity (95%CI), I2 | Pooled DOR (95%CI), I2 | |||||
| Various exclusion criteria | n/N | LUS | CXR | LUS | CXR | LUS | CXR |
| All included trials | 2470/22 | 0.95 (0.94–0.96), 59.5% | 0.91 (0.90–0.93), 85.3% | 0.90 (0.87–0.92), 82.0% | 1.00 (0.99–1.00), 0.0% | 137.49 (60.21–313.98), 65.2% | 369.66 (137.14–996,47), 52.9% |
| Number of patients ≤ 100 | 692/10 | 0.95 (0.93–0.97), 58.9% | 0.91 (0.88–0.93), 83.5% | 0.82 (0.75–0.87), 89.0% | 0.99 (0.96–1.00), 0.0% | 136.29 (25.33–733.44), 75.4% | 213.77 (61.34–745.06), 30.2% |
| Number of patients > 100 | 1778/12 | 0.95 (0.93–0.96), 62.9% | 0.92 (0.90–0.93), 87.5% | 0.92 (0.90–0.94), 45.2% | 1.00 (0.99–1.00), 9.9% | 147.76 (67.89–321.58), 39.4% | 599.85 (131.40–2738.44), 64.8% |
| Prospective study | 2043/17 | 0.94 (0.93–0.95), 60.0% | 0.92 (0.90–0.93), 85.8% | 0.91 (0.89–0.93), 73.2% | 1.00 (0.99–1.00), 0.0% | 144.24 (65.74–316.49), 53.2% | 572.95 (175.63–1869.11), 56.1% |
| Retrospective study | 427/5 | 0.97 (0.95–0.98), 45.2% | 0.90 (0.86–0.92), 86.2% | 0.76 (0.64–0.85), 91.2% | 0.98 (0.90–1.00), 0.0% | 116.26 (6.02–2244.15), 81.5% | 97.73 (19.19–497.66), 27.7% |
| Blind study | 2230/19 | 0.95 (0.94–0.96), 61.4% | 0.92 (0.90–0.93), 84.4% | 0.91 (0.89–0.93), 70.3% | 1.00 (0.99–1.00), 0.0% | 159.07 (76.26–331.80), 48.4% | 429.71 (145.65–1267.82), 54.9% |
| Non-blind study | 240/3 | 0.93 (0.89–0.96), 54.9% | 0.88 (0.83–0.92), 91.9% | 0.65 (0.49–0.79), 94.4% | 1.00 (0.89–1.00), 0.0% | 40.55 (0.65–2525.41), 86.1% | 147.60 (8.53–2553.79), 52.5% |
| Expert operator | 1342/14 | 0.96 (0.95–0.97), 50.2% | 0.90 (0.89–0.92), 82.3% | 0.91 (0.86–0.95), 83.9% | 0.99 (0.97–1.00), 0.0% | 220.82 (49.86–977.93), 69.5% | 160.33 (55.85–460.24), 32.1% |
| Non-expert operator | 1128/8 | 0.92 (0.90–0.94), 49.9% | 0.93 (0.91–0.95), 89.2% | 0.89 (0.86–0.92), 80.0% | 1.00 (0.99–1,00), 41.4% | 89.52 (36.64–2218.73), 59.9% | 1820.35 (250.85–13209.84), 68.4% |
| Ultrasound linear probe | 1267/11 | 0.94 (0.91–0.95), 56.6% | 0.91 (0.89–0.93), 85.9% | 0.90 (0.87–0.92), 80.0% | 0.99 (0.98–1.00), 31.3% | 120.02 (49.65–290.13), 56.7% | 528.92 (103.66–2698.84), 67.9% |
| Ultrasound convex probe | 383/3 | 0.95 (0.92–0.97), 85.2% | 0.94 (0.91–0.97), 85.9% | 1.00 (0.77–1.00), 0.0% | 1.00 (0.89–1.00), 0.0% | 127.57 (8.17–1992.19), 48.9% | 308.91 (15.84–6023.74), 56.0% |
| Linear + convex probe | 820/8 | 0.96 (0.94–0.97), 34.1% | 0.90 (0.88–0.92), 86.6% | 0.86 (0.79–0.92), 88.7% | 1.00 (0.97–1.00), 0.0% | 176.12 (21.46–1445.75), 78.7% | 260.70 (68.90–986.34), 21.9% |
CI = confidence interval, CXR = chest radiography, DOR = diagnostic odds ratio, LUS = lung ultrasound, n = patient number, N = study number.