TABLE 2.

The characteristics of the included participants.

Author, year	Age (years) Mean [95% CI] or Mean ± SD		Gender (male/total)		Smoking history Mean ± SD		FEV1/predicted (%) Mean ± SD		Concomitant respiratory medications			Diabetes
	Bacterial lysates	Control	Bacterial lysates	Control	Bacterial lysates	Control	Bacterial lysates	Control	Long-terms effect bronchodilator	Flu vaccination	Pneumonia vaccination	Bacterial lysates	Control
Avdeev et al. (8)	69.4 ± 9.4	69.9 ± 7.9	28/30	30/30	30/30	30/30	31.3 ± 8.7	33.2 ± 7.7	Yes	NR	NR	NR	NR
Zeng et al. (14)	70.1 ± 5.7	69.2 ± 6.1	67/78	63/72	63/78	61/72	49.15 ± 4.74	49.06 ± 2.73	Yes	No	No	NR	NR
Tang et al. (9)	63.0 ± 9.4	63.2 ± 8.9	141/192	133/192	123/192	120/192	54.0 ± 10.0	55.0 ± 9.7	Yes	Allowed	NO	NR	NR
Braido et al. (10)	69.3 ± 8.6	68.6 ± 9.4	107/146	91/142	123/146	120/142	52.18 ± 18.99	52.66 ± 16.26	Yes	Allowed	NR	19/146	10/142
Ricci et al. (13)	65–89		16/28		–	–	–	–	Yes	Allowed	NR	–	–
Nishantha et al. (15)	50–58		24/24	21/21	–	–	–	–	–	–	–	–	–
Cazzola et al. (17)	66.6 ± 7.8	66.2 ± 8.0	25/33	26/30	≥20/33	≥16/30	47.7 ± 9.0	46.2 ± 8.9	Yes	Allowed	NR	NR	NR
Solèr et al. (18)	57.3 [55.7, 58.9]	57.9 [56.2, 59.6]	78/142	57/131	87/142	77/131	85[81.7, 88.3]	82.6[79.9, 86.1]	Yes	Allowed	NR	NR	NR
Li et al. (19)	67 ± 4	65 ± 5	27/49	22/41	49/49	41/41	50.9 ± 21	53.2 ± 19.7	Yes (sustained- released theophylline)	NR	NR	NR	NR
Collet et al. (20)	65.3 ± 7.7	66.9 ± 7.7	133/191	135/190	78/191′	59/190′	67.7 ± 15.3	68.4 ± 15.6	NR	Allowed	NR	NR	NR
Xinogalos et al. (21)	56.03 ± 12.67	59.75 ± 12.89	–	–	–	–	–	–	–	–	–	–	–

FEV1/predicted, forced expiratory volume in one second/predicted value; NR, not reported.