Table 2.

Meta-regression of the effect of intervention´s characteristics on pooled glycated hemoglobin (N = 20)

				Number interventions a	SMD	95% CI	Residual I 2
Country							0.00%
		US		18	-0.28**	-0.47; -0.09
		Netherland		1	-0.82	-1.85; 0.21
		UK		1	-0.06	-0.88; 0.77
Year							1.74%
		Prior 2001		2	-0.51	-1.29; 0.26
		2001-2006		6	0.32	-0.52; 1.15
		2007-2012		12	0.18	-0.60; 0.97
Setting							0.00%
		Primary Care		9	-0.23	-0.58; 0.11
		Community center		6	-0.03	-0.48; 0.41
		Other		5	-0.24	-0.74; 0.26
Mean HbA1c at baseline in intervention group							0.08%
		HbA1c < 9%		10	-0.39**	-0.96; 0.17
		HbA1c ≥ 9%		10	0.06	-0.32; 0.43
Target population							3.33%
		Ethnic minority		10	-0.30	-0.58; -0.04
		Rural ethnic minority		3	0.31	-0.41; 1.03
		Women from ethnic minority group		2	-0.23	-1.04; 0.58
		Other (elderly or low income or low literacy)		5	-0.05	-0.47; 0.36
Ethnic minority group							0.00%
		African-American		7	-0.10	-0.48; 0.28
		Latinos		7	-0.31	-0.80; 0.17
		Asiatic		2	-0.54	-1.28; 0.20
		Multi-ethnic		4	-0.15	-0.66; 0.35
Individual Vs Group delivered							0.00%
		Individual		7	-0.45	-0.75; -0.14
		Group		7	0.13	-0.29; 0.56
		Both		4	0.32	-0.14; 0.79
Patients accompanied by family							0.00%
		No		5	-0.23**	-0.44; -0.04
		Yes		15	-0.38	-0.84; 0.07
Face to face Vs. telecommunication							0.00%
		Exclusively face to face		12	-0.37**	-0.62; -0.12
		Exclusively telecommunication		3	-0.08	-0.53; 0.37
		Combining face to face and telecommunication		5	0.33	-0.11; 0.77
Teaching methods							0.00%
		Didactic					0.39%
			Yes	14	-0.30**	-0.53; -0.07
			No	6	-0.03	-0.42; 0.35
		Goal setting negotiated					0.00%
			Yes	8	-0.29**	-0.57; -0.01
			No	12	-0.03	-0.41; 0.34
		Goal setting dictated					0.00%
			Yes	7	-0.26	-0.55; 0.02
			No	13	-0.09	-0.48; 0.29
		Situational problem solving					0.00%
			Yes	10	-0.28**	-0.50; -0.06
			No	10	-0.08	-0.47; 0.30
		Cognitive reframing					0.00%
			Yes	4	-0.47**	-0.91; -0.03
			No	16	0.20	-0.29; 0.68
		Number of teaching methods used					0.00%
			1	4	-0.58**	-1.04; -0.12
			2	10	0.37	-0.16; 0.92
			3 or more	4	0.27	-0.27; 0.80
Content
		Diet					0.00%
			Yes	18	-0.35*	-0.54; -0.15
			No	1	-0.74	-2.00; 0.50
		Exercise					0.00%
			Yes	15	-0.33*	-0.54; -0.12
			No	4	-0.20	-0.68; 0.28
		Blood glucose self-monitoring					0.00%
			Yes	13	-0.26*	-0.48; -0.03
			No	6	-0.39	-0.81; 0.04
		Basic diabetes knowledge					0.00%
			Yes	8	-0.28*	-0.53; -0.02
			No	11	-0.21	-0.60; 0.17
		Medication adherence					0.00%
			Yes	9	-0.25*	-0.49; -0.05
			No	10	-0.19	-0.58; 0.20
		Psycho-social					0.00%
			Yes	11	-0.18*	-0.40; 0.03
			No	9	-0.38	-0.76; 0.01
	Number of contents						5.17%
		1 or 2		4	-0.36	-0.84; 0.12
		3 or 4		9	0.02	-0.55; 0.58
		5 or more		7	0.84	-0.48; 0.65
Educators
		Nurse					2.59%
			Yes	5	-0.02	-0.43; 0.39
			No	14	-0.29*	-0.52; -0.06
		Dietician					0.77%
			Yes	11	-0.10	-0.27; 0.47
			No	8	-0.35*	-0.62; -0.08
		Psychologist					2.47%
			Yes	1	0.05	-0.65; 0.76
			No	18	-0.30*	-0.50; -0.11
		Physician					0.00%
			Yes	2	0.21	-0.29; 0.72
			No	17	-0.33*	-0.54; -0.13
		Research team					2.13%
			Yes	2	-0.10	-0.77; 0.58
			No	17	-0.29*	-0.49; -0.09
Number of types of educators							0.00%
		One		11	-0.30*	-0.55; -0.04
		Two		6	-0.41	-0.90; 0.07
		Three or more		2	0.17	-0.34; 0.70
Peer provider							0.00%
		Yes		7	-0.54	-0.93; -0.15*
		No		13	0.29	-0.15; 0.74
Duration of the intervention (months)				8.4 (1.4)†	-0.02	-0.05; 0.02
Number of sessions				12.1 (2.1)†	-0.01	-0.02; 0.01	0.00%
Average duration of each session (hours)				1.5 (0.2)†	-0.01	-0.25; 0.23	0.00%
Total hours of intervention				21.9 (7.0)†	-0.01	-0.01; 0.01	0.00%
Intensity (number of hours/month)				4.6 (1.3)†	-0.01	-0.09; 0.07	1.60%

SMD = standardized mean difference; I² = Variation in standardized mean difference attributable to heterogeneity; 95% CI = 95% confidence interval; HbA1c = glycated hemoglobin.

^aN is not equal to 20 for all variables, as some characteristics were not reported for all the interventions.

*p < 0.05; **p < 0.001, † = mean (SE).