Effect of shared decision-making on therapeutic alliance in addiction health care

Figures & data

Table 1 Baseline characteristics of the study population by condition (n = 147)

Characteristic	SDMI		Control		χ^2, p-value	t-value, p-value
		n		n
Age, mean (SD), years	40.7 (10.3)	64	41.2 (11.1)	83		0.27, 0.79
Gender, % male	76.6	49	75.9	63	0.01, 1.00
Country of birth, %					1.24, 0.27
Netherlands	92.2	59	96.4	80
Other	7.8	5	3.6	3
Relationship, %					2.68, 0.26
Married	12.7	8	20.7	17
Divorced/widow	44.4	28	32.9	27
Never married	42.9	27	46.3	38
Employment full or part-time %	62.9	39	53.8	42	1.16, 0.28
Years of education, mean (SD)	11.3 (2.7)	64	11.6 (3.1)	83		0.54, 0.59
Type of substance dependence, %
Alcohol dependence	71.9	46	74.7	62	0.15, 0.71
Drug dependence	43.8	28	37.3	31	0.62, 0.50
Years of substance use, mean (SD)	14.8 (8.3)	62	14.5 (10.0)	80		−0.17, 0.87
Primary substance use, %					1.03, 0.79
Alcohol	52.4	33	59.3	48
Cocaine/Stimulants	12.7	8	8.6	7
Polydrug	27	17	25.9	21
Other	7.9	5	6.2	5
EuropASI severity scores, mean (SD)		64		83
Physical health	2.4 (2.1)		2.8 (2.1)			1.10, 0.27
Work, education, and income	3.7 (1.7)		3.4 (2.0)			−1.00, 0.32
Alcohol	5.2 (2.6)		5.3 (2.5)			0.34, 0.73
Drugs	3.4 (3.3)		2.9 (3.2)			−0.92, 0.36
Legal	1.5 (1.9)		1.4 (1.8)			−0.12, 0.91
Family/social relations	3.8 (1.5)		4.4 (1.5)			2.46, 0.02*
Psych./emotional problems	5.8 (2.0)		5.8 (2.0)			0.03, 0.97
Gambling	0.5 (1.5)		0.4 (1.2)			0.20, 0.85

* p < 0.05.

Table 2 Baseline characteristics of the clinicians by condition (n = 34)

Characteristic	SDMI		Control		χ^2 p-value	t-value, p-value
		n		n
Age, mean (SD), years	35.6 (12.4)	16	34.1 (12.0)	18		0.36, 0.72
Gender, % male	31.3	5	44.4	8	0.62, 0.50
Years of working experience, mean (SD)	13.1 (11.6)	16	12.6 (11.5)	18		0.13, 0.90

Table 3 Patient’s and clinician’s perceived alliance (HAQ) at interim and exit measurement

HAQ Mean (SD)	n	SDMI	n	Control	n	Total	t-value	P-value	ES d
Patient
Interim (T3)
Cooperation	54	20.1 (2.5)	66	19.7 (3.7)	120	19.9 (3.1)	0.73	0.46	0.13
Helpfulness	55	20.1 (2.6)	66	20.2 (2.8)	121	20.2 (2.7)	−0.10	0.92	0.04
Total	54	44.7 (4.1)	66	44.1 (6.3)	120	44.4 (5.4)	0.61	0.55	0.11
Patient
Exit (T4)
Cooperation	50	20.5 (2.7)	53	21.2 (3.2)	103	20.8 (3.0)	−1.13	0.26	0.24
Helpfulness	50	21.7 (2.3)	54	21.8 (3.0)	104	21.8 (2.7)	−0.14	0.89	0.04
Total	50	46.6 (4.7)	53	47.5 (6.3)	103	47.1 (5.6)	−0.82	0.42	0.16
Clinician
Interim (T3)
Cooperation	52	18.9 (2.3)	71	18.6 (2.3)	123	18.7 (2.3)	0.63	0.53	0.13
Helpfulness	53	19.0 (2.4)	73	17.8 (3.2)	126	18.3 (3.0)	2.44	0.02*	0.42
Total	52	42.2 (4.4)	71	40.2 (5.4)	123	41.0 (5.1)	2.01	0.05*	0.41
Clinician
Exit (T4)
Cooperation	49	18.9 (2.3)	47	18.3 (2.5)	96	18.6 (2.4)	1.10	0.27	0.25
Helpfulness	49	19.5 (2.6)	47	17.6 (4.1)	96	18.6 (3.5)	2.82	0.01**	0.55
Total	48	42.6 (4.2)	47	39.4 (6.0)	95	41.0 (5.4)	3.01	0.01**	0.62

* p < 0.05.

** p < 0.01.

Table 4 Difference score (patient minus clinician) HAQ at interim and exit measurement

HAQ Mean (SD)	n	SDMI	n	Control	n	Total	t-value	P-value
Interim (T3)
Cooperation	49	1.3 (2.8)	63	1.1 (3.8)	112	1.2 (3.4)	0.31	0.75
Helpfulness	50	1.4 (2.9)	65	2.5 (4.4)	115	2.0 (3.8)	−1.66	0.10
Total	49	2.9 (5.3)	63	3.9 (8.1)	112	3.5 (7.0)	−0.79	0.43
Exit (T4)
Cooperation	47	1.3 (2.9)	41	2.5 (3.4)	88	1.9 (3.2)	−1.70	0.09
Helpfulness	48	2.1 (2.9)	41	3.6 (4.2)	89	2.8 (3.7)	−1.88	0.06
Total	47	3.7 (5.4)	41	7.0 (7.3)	88	5.3 (6.5)	−2.44	0.02*

* p < 0.05.