Table 2.

Subgroup analysis of diagnostic accuracy for chest radiography and ultrasonography in detection of thoracic bone fractures

	No. of studies	Bivariate random-effect model
		Sensitivity (95% CI)	P	Specificity (95% CI)	p	heterogeneity, I 2	P *
Ultrasonography
Patient enrollment
Consecutive	3	0.98 (0.95-1.00)	0.01	0.90 (0.77-1.00)	0.55	43.0 %	0.18
Convenience	6	0.95 (0.90-0.99)		0.91 (0.86-0.96)
Operator
Emergency physician	3	0.90 (0.81-0.98)	<0.001	0.90 (0.83-0.97)	0.09	21.0 %	0.28
Other physician	6	0.96 (0.93-0.99)		0.91 (0.84-0.98)
Sample size
< 100	6	0.91 (0.84-0.97)	0.01	0.90 (0.83-0.97)	0.04	12.0 %	0.32
≥ 100	3	0.97 (0.94-1.00)		0.93 (0.87-0.98)
Frequency of transducer
5-10 MHz	6	0.94 (0.89-0.99)	0.62	0.90 (0.85-0.95)	0.03	0.0 %	0.51
10-15 MHz	3	0.95 (0.88-1.00)		0.95 (0.89-1.00)
Type of fracture
Rib	4	0.97 (0.93-1.00)	0.01	0.89 (0.83-0.96)	0.01	45.0 %	0.16
Sternum / Clavicle	5	0.91 (0.84-0.97)		0.93 (0.94-0.98)
Radiography
Patient enrollment
Consecutive	7	0.80 (0.59 - 1.00)	0.70	1.00 (1.00 - 1.00)	0.99	0.0 %	0.70
Convenience	5	0.73 (0.45 - 1.00)		1.00 (0.98 - 1.00)
Operator
Emergency physician	3	0.66 (0.27 - 1.00)	0.53	1.00 (1.00 - 1.00)	0.99	0.0 %	0.78
Other physician	9	0.80 (0.63 - 0.98)		1.00 (1.00 - 1.00)
Sample size
< 100	7	0.73 (0.49 - 0.97)	0.44	1.00 (1.00 - 1.00)	0.99	0.0 %	0.57
≥ 100	5	0.82 (0.61 - 1.00)		1.00 (1.00 - 1.00)
Type of fracture
Rib	8	0.77 (0.57 - 0.97)	0.56	1.00 (1.00 - 1.00)	0.99	0.0 %	0.98
Sternum / Clavicle	4	0.77 (0.48 - 1.00)		1.00 (1.00 - 1.00)

^*, P value < 0.1 was considered as significant for heterogeneity; CI: Confidence interval.