Table 1.

Characteristics of included studies.

First author, year	No. of participants randomized/assessed; dropouts	Age; Gender (M/F)	COPD stage	Duration of condition (years)	Treatment duration; follow-up duration (months)
Bai SR, 2016	T:90/85;5	T:58.7(12.5);49/41	II,III	T:6.5(3.3)	T:6;0
	C:90/83;7	C:59.3(13.2):51/39		C:6.3(3.2)	C:6;0
Cao DC, 2016	T:50/50;0	T:66.33(4.21);30/20	II	NS	T:3;0
	C:50/50;0	C:64.45(5.11);28/22			C:3:0
Dong KZ, 2016	T:25/25;0	T:65.2(3.2);18/7	II,III	NS	T:3;0
	C:25/25;0	C:66.8(2.7);17/8			C:3:0
Fei DL, 2010	T: 45/45;0	T:59.7(4.5);28/17	II,III	T:10.5(4.9)	T: 3;0
	C: 45/45;0	C:57.9(4.1);26/19		C:11.5(5.2)	C: 3;0
He WJ, 2010	T: 24/22;2	T:55.36(9.03);15/7	II,III	T:12.22(2.75)	T: 3;0
	C: 24/23;1	C:57.13(8.77);17/6		C:11.56(3.08)	C: 3;0
Hu QG, 2012	T: 51/51;0	T:65.41(12.23);34/17	II,III	NS	T: 6;0
	C: 50/50;0	C:64.86(11.84);34/16			C: 6;0
Huang DH, 2005	T: 32/32;0	T:69.5(11.8);21/11	II,III	T:8.5(3.2)	T: 3;0
	C: 31/31;0	C:68.8(10.6);23/8		C:8.3(3.5)	C: 3;0
Liu JS, 2014	T: 40/40;0	Total:64.2(2.4);82/38	II,III	Total:15.2(3.9)	T: 12;0
	C: 40/40;0				C: 12;0
Luo SW,2015	T: 51/51;0	T:72.3(8.5);33/18	II,III	T:14.7(5.3)	T: 2;0
	C: 51/51;0	C:73.5(8.9);34/17		C:15.1(5.7)	C: 2;0
Tang CY, 2009	T: 30/30;0	T:63.2∗;27/3	II,III	T:7.2∗	T: 6;6
	C: 30/30;0	C:65.5∗;26/4		C:7.5∗	C: 6;6
Wu HL, 2016	T:46/46;0	T:66.58(7.12);31/15	II,III	T:5.82(1.64)	T:2;0
	C:32/32;0	C:66.34(7.09);21/11		C:6.03(1.71)	C:2;0
Xin DY, 2015	T: 41/41;0	T:58.6;21/20	II,III	T:10.2∗	T: 1;0
	C: 39/39;0	C:57.9;19/20		C:10.8∗	C: 1;0
Yao JF, 2013	T:30/27;3	T:67.48(6.99);18/9	III	T:6.33(4.01)	T: 3;0
	C:30/25:5	C:67.68(7.76);18/7		C:4.68(3.16)	C: 3;0
Zhou Y, 2014	T:50/50;0	T:62.8(6.2);29/21	II	T:14.5(8.5)	T: 6;6
	C:50/50;0	C:61.6(7.4);30/20		C:13.5(9.5)	C: 6;6

∗ median.