Table 3.

Subgroup analysis on primary outcome of clinical response.

		Studies number	Patient number	Event in NA group	Event in control group	Risk ratio (95% CI)	I2	P
Types of nebulizers	Vibrating mesh nebulizer	3	698	191 of 358	177 of 340	0.99 [0.87, 1.13]	0%	0.90
	Ultrasonic nebulizer	2	114	23 of 59	14 of 57	1.64 [1.07, 2.53]	0%	0.003
	Jet nebulizer	8	778	255 of 390	185 of 388	1.37 [1.22, 1.55]	0%	< 0.0001
Patients with resistant GNP	100%	4	210	73 of 107	45 of 103	1.58 [1.24, 2.00]	0%	0.0002
	< 100%	9	1,240	401 of 629	324 of 611	1.24 [1.08, 1.42]	54%	0.003
Dose of NA	≥ 800 mg/day	7	652	301 of 462	254 of 460	1.25 [1.04, 1.51]	59%	0.02
	< 800 mg/day	7	542	173 of 272	129 of 270	1.33 [1.16, 1.53]	35%	< 0.0001
Sample size	< 100	9	570	223 of 295	145 of 275	1.28 [0.78, 2.12]	40%	< 0.0001
	> 100	4	880	251 of 441	224 of 439	1.19 [0.94, 1.50]	63%	0.15
Study quality	Low	9	700	273 of 351	186 of 349	1.46 [1.31, 1.63]	0%	< 0.0001
	High	4	750	201 of 385	183 of 365	1.01 [0.89, 1.16]	0%	0.84
Study design	Blinded	4	750	201 of 385	183 of 365	1.01 [0.89, 1.16]	0%	0.84
	Unblinded	9	700	23 of 30	14 of 30	1.46 [1.31, 1.63]	0%	< 0.0001

NA = nebulized amikacin; CI = confidence interval; GNP = gram‑negative pneumonia.