Population Related Factors
	Active Group									Sham Group
	95%CI									95%CI
Variables	n	τ2	Adj. R2	β	SE	t	p	LB	UP	n	τ2	Adj. R2	β	SE	t	p	LB	UP
Average age	23	1.83	1.15	−0.06	0.06	−1.04	0.31	−0.19	0.06	23	1.76	4.52	−0.09	0.08	−1.20	0.24	−0.26	0.07
Duration of symptoms (months)	8	2.99	0.64	−0.01	0.01	−1.06	0.33	−0.05	0.02	8	2.95	0.73	−0.01	0.01	−1.10	0.31	−0.04	0.02
Percentage of women	26	1.91	0.36	−0.02	0.02	−0.85	0.40	−0.05	0.02	26	1.80	6.38	−0.02	0.02	−1.25	0.23	−0.06	0.02
Body mass index	7	2.64	17.21	−0.73	0.51	−1.43	0.21	−2.04	0.58	7	3.91	22.42	0.37	0.60	0.61	0.57	−1.18	1.91
Number of subjects with another chronic illness	6	6.42	21.10	0.10	0.19	0.51	0.63	−0.43	0.63	6	6.70	26.46	0.07	0.19	0.35	0.74	−0.46	0.60
Baseline depression level	14	2.48	2.18	−0.81	0.75	−1.09	0.30	−2.44	0.81	14	2.48	2.18	−0.08	0.75	−1.09	0.30	−2.44	0.81
Baseline anxiety level	7	3.33	6.21	−0.76	0.84	−0.90	0.41	−2.93	1.41	7	3.31	5.36	−0.73	0.80	−0.92	0.40	−2.79	1.33
Baseline pain catastrophizing score	5	3.70	33.52	0.17	0.23	0.75	0.51	−0.55	0.89	5	3.86	39.35	−0.19	0.33	−0.58	0.61	−1.23	0.85
Percentage of subjects using opioids†
Disability score at baseline	14	0.62	7.92	−0.02	0.25	−0.78	0.45	−0.07	0.04	14	0.65	4.07	−0.02	0.23	−0.97	0.35	−0.07	0.03
Sleep quality score at baseline	7	2.90	8.46	0.01	0.08	1.14	0.31	−0.12	0.31	7	3.10	15.95	0.09	0.09	0.99	0.37	−0.15	3.91

^†Calculation not possible due to low number of observations