Table 2.

Subgroup analysis of diagnostic accuracy for chest radiography and ultrasonography in detection of hemothorax

Covariate	No. of studies	Bivariate random-effect model
		Sensitivity (95% CI)	P	Specificity (95% CI)	p	Heterogeneity, I 2	P *
Ultrasonography
Patient enrollment
Consecutive	3	0.76 (0.45-1.00)	0.56	1.00 (0.99-1.00)	0.86	10.00 %	0.33
Convenience	5	0.61 (0.31-0.92)		0.97 (0.93-1.00)
Operator
Emergency physi   cian	5	0.70 (0.42-0.99)	0.68	0.99 (0.98-1.00)	0.02	0.00 %	0.59
Other physician	3	0.62 (0.23-1.00)		0.97 (0.90-1.00)
Sample size
< 100	5	0.70 (0.41-0.98)	0.72	0.99 (0.97-1.00)	0.08	0.00 %	0.74
≥ 100	3	0.63 (0.24-1.00)		0.98 (0.95-1.00)
Frequency of transducer
1-5 MHz	5	0.64 (0.37-0.92)	0.55	0.99 (0.97-1.00)	0.12	0.00 %	0.94
5-10 MHz	3	0.75 (0.37-1.00)		0.99 (0.95-1.00)
Radiography
Patient enrollment
Consecutive	3	0.61 (0.24-0.98)	0.65	0.98 (0.94-1.00)	0.03	0.00 %	0.88
Convenience	6	0.51 (0.23-0.78)		0.99 (0.97-1.00)
Operator
Emergency physi   cian	5	0.54 (0.24-0.84)	0.96	0.99 (0.97-1.00)	0.07	0.00 %	0.99
Other physician	4	0.55 (0.22-0.87)		0.99 (0.96-1.00)
Sample size
<100	3	0.69 (0.38-1.00)	0.32	0.94 (0.81-1.00)	0.38	0.00 %	0.99
≥ 100	6	0.46 (0.21-0.72)		0.99 (0.99-1.00)

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