Do drug treatment variables predict cognitive performance in multidrug-treated opioid-dependent patients? A regression analysis study

Table 3 Hierarchical regression results for combined reaction times in the Alertness test by opioid drug group

Buprenorphine-treated patients (n = 51)
Predictors in the reduced model	Step1 Beta (t-test)^a,b	Step2 Beta (t-test)	Step3 Beta (t-test)	Step4 Beta (t-test)
Drug treatment variables
BZD treatment (yes vs. no)	.34	.36	.37	.38
	t(49) = 2.51	t(48) = 2.64	t(47) = 2.60	t(46) = 2.60
	p = 0.015*	p = 0.011*	p = 0.012*	p = 0.013*
Buprenorphine dose (high vs. low)^c		-.16	-.17	-.19
The number of psychoactive drugs, other than opioid or BZD (high vs. low)^d			.05	.05
Duration of OST (long vs. short)^e				-.05
R² (adjusted)	.096	.103	.084	.069
Model (ANOVA)^a	F(1,49)= 6.29	F(2,48)= 3.88	F(3,47) = 2.58	p = 0.12
Model (ANOVA)^a	p = 0.015*	p = 0.027*	p = 0.065#
Change (ANOVA)^a		p = 0.24	p = 0.76	p = 0.71
Methadone-treated patients (n = 51)
Predictors in the reduced model	Step1 Beta ( t -test) ^a,b	Step2 Beta ( t -test)	Step3 ^f Beta ( t -test)
Drug treatment variables
The number of psychoactive drugs, other than opioid or BZD (high vs. low)	.27 #	.30 *	. 31 *
	t(49) = 1.92	t(48) = 2.21	t(47) = 2.09
	p = 0.060#	p = 0.032*	p = 0.042*
Methadone dose BZD treatment (yes vs. no)		.26 #	.26 #
		t(48) = 1.88	t(47) = 1.86
		p = 0.066#	p = 0.069#
			-.02
R² (adjusted)	.051	.098	.073
Model (ANOVA)^a	F(1,49) = 3.71	F(2,48) = 3.72	F(3,47) = 2.43
Model (ANOVA)^a	p = 0.060#	p = 0.032*	p = 0.077 #
Change (ANOVA)^a		0.066 #	0.90

^aOnly p-value shown when p ≥ 0.10.
^bSigns of beta values are reversed so that positive values refer to slowing of reaction times.
^cConsidered as low up to 16 mg.
^dConsidered as low up to one drug.
^eConsidered as short when between six and twelve months.
^fStep 4 is not shown because ‘the duration of OST’ variable correlated strongly (.61) with methadone dose producing a multicollinearity condition, and on a theoretical basis it was excluded from the analyses.
*p < 0.05. #p < 0.10.

ISSN: 1747-597X