Table 3.

Meta-regression based moderator analyses

Outcome variable	Moderator variable	Ka	Slope	95% CI	p value
All interventions
Gambling severity	Modality – CBT vs. MI/CBT	18/7	0.27	[−0.48; 1.01]	0.4830
	CBT vs. Other	5	−0.14	[−1.02; 0.74]	0.7565
	CBT vs. MI	3	0.85	[−0.18; 1.88]	0.1048
	Mode of delivery – face-to-face vs. remote	16/13	0.64	[0.06; 1.23]	0.0306
	Type of control group – passive vs. active	19/13	0.73	[0.21; 1.25]	0.0063
	GD as eligibility criterion – yes vs. no	14/14	1.05	[0.56; 1.55]	<0.0001
	Comorbidity excluded – no vs. yes	11/17	<0.01	[−0.67; 0.68]	0.9939
	Therapist fidelity assessment – no vs. yes	9/14	0.15	[−0.62; 0.91]	0.7110
	Proportionb with GD	26	−0.16	[−0.28; −0.04]	0.0116
	Proportionb female	28	0.00	[−0.17; 0.16]	0.9562
	Proportionb married	13	−0.13	[−0.28; 0.01]	0.0669
	Sample mean age	27	−0.04	[−0.08; 0.00]	0.0610
	No. of contact sessionsc	25	−0.05	[−0.09; −0.01]	0.0156
	Length of treatment periodd	27	−0.09	[−0.15; −0.03]	0.0053
	Date of publication (years until 2021)	28	0.09	[0.05; 0.12]	<0.0001
Remission	Mode of delivery – face-to-face vs. remote	7/6	1.07	[0.03; 2.10]	0.0446
	Type of control group – passive vs. active	7/6	0.70	[−0.53; 1.92]	0.2655
	GD as eligibility criterion – yes vs. no	5/7	1.56	[0.50; 2.61]	0.0039
	Comorbidity excluded – no vs. yes	5/7	0.38	[−0.99; 1.74]	0.5902
	Therapist fidelity assessment – no vs. yes	3/7	0.72	[−1.31; 2.75]	0.4859
	Proportionb with GD	12	−0.14	[−0.40; 0.13]	0.3246
	Proportionb female	12	−0.06	[−0.49: 0.37]	0.7848
	Sample mean age	11	−0.07	[−0.15; 0.00]	0.0634
	No. of contact sessionsc	11	−0.02	[−0.11; 0.08]	0.7470
	Length of treatment periodd	12	−0.08	[−0.23; 0.07]	0.3075
	Date of publication (years until 2021)	12	0.12	[0.03; 0.20]	0.0065
Face-to-face intervention
Gambling severity	Format – individual vs. group	10/6	−0.45	[−1.55; 0.66]	0.4272
	Type of control group – passive vs. active	11/7	1.03	[0.23; 1.84]	0.0116
	GD as eligibility criterion – yes vs. no	11/5	1.42	[0.63; 2.21]	<0.0001
	Comorbidity excluded – no vs. yes	5/11	1.13	[0.05; 2.22]	0.0408
	Therapist fidelity assessment – no vs. yes	4/12	0.76	[−0.42; 1.95]	0.2078
	Proportionb with GD	15	−0.39	[−0.77; −0.02]	0.0386
	Proportionb female	16	−0.08	[−0.32; 0.17]	0.5489
	Sample mean age	15	−0.04	[−0.11; 0.03]	0.2659
	No. of contact sessionsb	15	−0.10	[−0.16; −0.05]	0.0004
	Length of treatment periodc	15	−0.09	[−0.17; −0.01]	0.0234
	Date of publication (years before 2021)	16	0.12	[0.05; 0.19]	0.0004
Remote intervention
Gambling severity	Therapist guidance – guided vs. unguided	6/8	0.22	[−0.38; 0.82]	0.4703
	Type of control group – passive vs. active	9/6	0.36	[−0.16; 0.88]	0.1765
	GD as eligibility criterion – yes vs. no	4/9	0.27	[−0.39; 0.92]	0.4254
	Comorbidity excluded – no vs. yes	6/7	−0.48	[−1.03; 0.06]	0.0801
	Proportionb with GD	12	−0.07	[−0.16; 0.03]	0.1628
	Proportionb female	13	0.04	[−0.15; 0.23]	0.6930
	Sample mean age	13	−0.01	[−0.05; 0.02]	0.4667
	Length of treatment periodc	13	−0.03	[−0.13; 0.08]	0.6275
	Date of publication (years until 2021)	13	0.03	[−0.04; 0.10]	0.3758

Bold p-values indicate statistical significance (<0.05); β, slope of the regression; CBT, cognitive behavioral therapy; CI, confidence interval; GD, gambling disorder; K, number of parameters in the analysis; MI, motivational intervention; SE, standard error, a) for dichotomous variables: contrast/comparator, b) the correlation coefficient corresponds to a 10% change in this variable, c) if a study had multiple intervention groups with different number of contact sessions, the minimum value was used in the regression, d) if a study had multiple intervention groups with different length of treatment, the minimum value was used in the regression.