Baseline predictors of treatment outcome in Internet-based alcohol interventions: a recursive partitioning analysis alongside a randomized trial

Table 2 Treatment response and odds ratios for the three subgroups resulting from classification tree analysis

	Subgroup
Characteristic	I (n= 31)	II (n= 29)	III (n= 76)	F / Fisher’s exact	p
Living alone	31 (100%)	0 (0%)	0 (0%)	134.564	0.000*
Interpersonal sensitivity	0.98 (0.63)	1.83 (0.53)	0.52 (0.32)	85.548	0.000*
Hostility	0.68 (0.59)	1.04 (0.67)	0.48 (0.42)	11.863	0.000*
Cognitive working ability	3.40 (0.77)	3.07 (0.88)	3.68 (0.70)	7.028	0.001*
Treatment response	8 (26%)	21 (72%)	31 (41%)	13.884	0.001*
IT intervention	14 (45%)	16 (55%)	38 (50%)	0.618	0.716
Treatment response (OR [95% CI])	0.50 [0.20, 1.27]	3.81 [1.50, 9.67]	1
Women	16 [52%]	15 (52%)	39 (51%)	0.038	1.000
Age	41.5 (11.4)	40.7 (9.4)	41.8 (9.4)	0.140	0.870
Education				4.468	0.336
Low	2 (7%)	4 (14%)	3 (4%)
Medium	15 (50%)	11 (39%)	28 (39%)
High	13 (43%)	13 (46%)	41 (57%)
Employed	24 (77%)	23 (82%)	66 (87%)	1.662	0.413
Residential urbanization level				3.923	0.419
Low	3 (10%)	5 (17%)	7 (9%)
Medium	7 (23%)	11 (38%)	25 (33%)
High	21 (68%)	13 (45%)	43 (57%)
AUDIT composite score	18.5 (5.8)	20.9 (4.4)	18.9 (5.2)	1.859	0.160
Years of alcohol problems	4.2 (4.7)	6.6 (6.8)	5.3 (5.6)	1.291	0.278
Drinks per week	40.6 (25.9)	48.1 (23.5)	44.2 (25.4)	0.666	0.516
Drinking days per week	5.7 (2.0)	5.9 (1.7)	5.8 (1.8)	0.059	0.943
Cannabis lifetime use	11 (36%)	8 (28%)	31 (41%)	1.556	0.443
Cocaine lifetime use	2 (7%)	8 (28%)	18 (24%)	5.512	0.061
Amphetamine lifetime use	3 (10%)	6 (21%)	17 (22%)	2.335	0.323
QOLS composite score	69.8 (17.0)	64.4 (15.2)	76.4 (17.3)	5.726	0.004
EQ-5D score	0.76 (0.23)	0.72 (0.27)	0.84 (0.12)	4.859	0.009
BSI global severity index	0.88 (0.48)	1.39 (0.40)	0.53 (0.31)	47.790	0.000*

Presented data are counts (%) or mean (SD) unless indicated otherwise; OR [95% CI] indicates odds ratios and their respective 95% confidence interval [lower, upper]. Subgroup III is the reference category; Education classification according to International Standard Classification of Education standard [34]; AUDIT = Alcohol Use Disorders Identification Test; QOLS = Flanagan Quality of Life Scale; EQ-5D = 5 dimensional EuroQol instrument, score calculated using the MVH-A1 algorithm from Dolan [35]; BSI = Brief Symptom Inventory; * Significant at α = 0.05 level, after Bonferroni correction for 21 variables in this table: corrected α = 0.05 / 21 = 0.0024.

ISSN: 1471-2458