Table 2. Subgroup analysis of PSS.

Subgroups	PSS
	Studies, n	Participants, n	I 2	Q-test	Mean difference	95% CI	P
Publication date
>2017 or = 2017	2	444	56	0.13	-0.75	-2.63,1.12	0.43
<2017	2	140	0	0.48	-1.82	-2.12,-1.52	<0.00001
Treatment duration
<7 weeks	2	389	88	0.004	-1.69	-1.98,-1.39	<0.00001
>7 weeks	2	195	0	0.74	-2.30	-3.78,-0.81	0.002