Table 4

Main effect of treatment and treatment by recruitment source interaction on estimated mean change in self-rated depressive symptoms (PHQ-9) from baseline to post and follow-up and minimally clinically relevant change of PHQ-9 at post-assessment. The sum of participants in the treatment groups (intervention plus CAU) is smaller than the number of participants in each subgroup because some participants did not complete the post or the follow-up assessment and could therefore not be included in the main analysis. A sensitivity analysis using multiple imputation to replace missing values yielded essentially the same results as the main analysis

Recruitment source	Treatment	Estimated change			Effect Size		Minimally clinically important change of PHQ-9		Effect size
Recruitment source	Treatment	M	SE	95% CI	d	95% CI	n	%	NNT	95% CI
Main effect of treatment		F_1,823 =21.84, p<0.001					B=1.18 (SE 51), p=0.021
All (n=1013)	Intervention (n=509)	2.94	0.21	2.53 to 3.35	0.30	0.01 to 0.59	143	28.1	9	6 to 15
All (n=1013)	CAU (n=504)	1.51	0.21	1.09 to 1.92	0.30	0.01 to 0.59	83	16.5	9	6 to 15
Treatment by recruitment source interaction		F_3,817 =0.29, p=0.83					B=−0.16 (SE 16), p=0.31
Clinical (n=105)	Intervention (n=42)	3.30	0.54	2.24 to 4.37	0.27	−0.49 to 1.04	17	29.8	5	−3 to 107
	CAU (n=38)	2.35	0.58	1.21 to 2.49	0.27	−0.49 to 1.04	8	16.7	5	−3 to 107
Internet forums (n=171)	Intervention (n=63)	2.20	0.46	1.30 to 3.10	0.39	−0.23 to 1.01	23	28.0	5	3 to 15
	CAU (n=62)	0.81	0.45	−0.07 to 1.69	0.39	−0.23 to 1.01	9	10.1	5	3 to 15
Insurance (n=271)	Intervention (n=106)	3.24	0.35	2.56 to 3.93	0.48	0.00 to 0.96	40	29.9	7	4 to 39
	CAU (n=113)	1.52	0.34	0.85 to 2.19	0.48	0.00 to 0.96	26	19.0	7	4 to 39
Other (n=466)	Intervention (n=184)	3.00	0.27	2.48 to 3.52	0.46	0.09 to 0.83	63	26.7	8	5 to 28
	CAU (n=186)	1.34	0.27	0.81 to 1.87	0.46	0.09 to 0.83	40	17.4	8	5 to 28