Table 2.

Subgroup analyses of social media-based intervention on weight (kg) in 20 randomised controlled trials with 21 arms.

Characteristics	Subgroups	No. of arm	Sample size	g	95% CI		Z-value	P-value	I2	Subgroup differences (Q-value), P-value
					lower	Upper
Geographical regions	Non-United States	5	348	−0.52	−0.82	−0.21	−3.27	0.001**	47.25%	Q = 3.211 P = 0.073
	United States	16	1772	−0.20	−0.35	−0.06	−2.67	0.007**	46.89%
Participants’ gender	Female only	6	171	−0.41	−0.76	−0.06	−2.32	0.020*	22.37%	Q = 2.927 P = 0.231
	Male only	1	50	−0.71	−1.27	−0.14	−2.45	0.014*	NA
	Mixed	15	1899	−0.24	−0.40	−0.08	−2.93	0.003**	60.30%
Theoretical basis	No	7	902	−0.26	−0.54	−0.02	−1.82	0.07	67.0%	Q = 0.098 P = 0.755
	Yes	14	1218	−0.31	−0.48	−0.14	−3.50	<0.001***	48.30%
Protocol or register	No	3	228	−0.80	−1.17	−0.44	−4.294	<0.001***	36.25%	Q = 10.223 P = 0.001**
	Yes	18	1892	−0.17	−0.29	−0.05	−2.822	0.005**	29.46
Use of ITT or M DM	No	4	251	−0.58	−1.19	0.02	−1.890	0.059	79.23%	Q = 1.527 P = 0.217
	Yes	17	1869	−0.20	−0.32	−0.07	−3.154	0.002**	29.74%
Type of social media platform	Existing social network	1	27	0.09	−0.64	0.82	0.24	0.81	NA	Q = 7.286 P = 0.200
	Facebook	9	1071	−0.40	−0.67	−0.14	−2.95	<0.001***	71.82%
	Facebook + Instagram	1	57	−0.51	−1.03	0.01	−1.92	0.05	NA
	Facebook + Youth	1	50	−0.70	−1.27	−0.14	−2.45	0.01*	NA
	Purpose-designed online social networks	8	819	−0.18	−0.37	0.02	−1.79	0.07	33.62%
	Twitter	1	96	−0.03	−0.43	0.37	−0.15	0.88	NA

CI Confidence interval, g Hedges’s g (effect size), ITT Intention-to-treat, MDM Missing data management, NA Non-applicable, protocol published trial’s protocol, Q Cohan Q, register registration in clinical trials, Z Z statistics.

***P < 0.001; **P < 0.01; *P < 0.05.