Table 5c.

Covariates associated with opioid-free time, defined as the duration of opioid-free time while on prescribed buprenorphine

Covariates	Proportion of all urine samples collected that were negative for opioids X [duration of BMT - gap times] (Duration of opioid-free time)
	Univariate Analysis			Multivariate Analysis
	OLS			OLS
	Beta	95% CI	P value	Beta	95% CI	P value
Age	2.44	(0.04, 4.82)	0.05	2.08	(−0.29, 4.44)	0.09
Gender
Male	Ref
Female	28.36	(−19.0, 75.8)	0.24
Site
Site 1	Ref
Site 2	16.58	(−28.1, 61.2)	0.47
Specialty
Psychiatry	Ref
Primary Care Provider	27.37	(−20.0, 75.3)	0.26
Baseline Cocaine Screen
Negative	Ref			Ref
Positive	−50.05	(−102, 2.05)	0.06	−50.42	(−99.1, −0.36)	<0.05
Any Cocaine Screen
Negative	Ref
Positive	−41.60	(−86.1, 3.52)	0.07	*
Receipt of on-site substance abuse counseling
No	Ref			Ref
Yes	44.65	(0.90, 88.3)	0.05	39.87	(−3.55, 83.3)	0.07
Mood disorder
No	Ref			Ref
Yes	72.00	(23.8, 120.)	<0.01	65.9	(18.23, 113.6)	<0.01
Prescribed psychiatric medication
No	Ref
Yes	62.72	(17.2, 108.)	0.01	*
HIV-infected
No	Ref
Yes	−11.04	(−39.0, 17.8)	0.45
HCV-infected
No	Ref
Yes	−0.35	(−18.2, 17.9)	0.97
AIC Goodness of Fit					3512.2

^*Non-significant variables were excluded by AIC/criteria in the multivariate model

BMT = buprenorphine maintenance therapy; Ref = referent; AIC = Akaike Information Criterion; GLM=Generalized Linear Model; OLS= Ordinary Least Square Regression