Table 2.

Secondary Outcomes

		% (95% CI)
Outcome	Time	Detoxification Group	12-Week Buprenorphine-Naloxone Group		OR (95% CI) GEE Score Test of Group Effect
Weeks 4, 8, and 12
Retention in trial	4 wk	45 (34-56)	84 (75-93)		0.13 (0.07-0.26) ${\mathrm{\chi }}_1^2$ = 32.90, P < .001
	8 wk	27 (17-37)	74 (64-84)
	12 wk	21 (12-30)	70 (59-81)
Nonstudy treatment	1-12 wk	35 (24-46)	4 (0-9)		13.09 (3.73-45.89) ${\mathrm{\chi }}_1^2$ = 25.82, P < .001
Any opioid use past week (self-report)	4 wk	63 (49-77)	26 (14-38)		4.30 (2.25-8.22) ${\mathrm{\chi }}_1^2$ = 18.45, P < .001
	8 wk	52 (37-67)	19 (8-30)
	12 wk	55 (40-70)	38 (24-52)
Any alcohol use past week (self-report)	4 wk	46 (31-61)	28 (16-40)		1.35 (0.66-2.77) ${\mathrm{\chi }}_1^2$ = 0.64, P = .42
	8 wk	36 (21-51)	29 (16-42)
	12 wk	24 (11-37)	22 (10-34)
Any marijuana use past week (self-report)a	4 wk	24 (11-37)	9 (1-17)		6.15 (2.10-18.01) ${\mathrm{\chi }}_1^2$ = 12.23, P = .001
	8 wk	19 (7-31)	6 (0-13)
	12 wk	26 (12-40)	16 (6-26)
Any cocaine use past week (self-report)a	4 wk	15 (4-26)	2 (0-6)		16.39 (3.07-87.47) ${\mathrm{\chi }}_1^2$ = 14.47, P = .001
	8 wk	14 (3-25)	2 (0-6)
	12 wk	12 (2-22)	2 (0-6)
Counseling sessions attended, mean, No.b	1-12 wk	5.06 (3.62-6.50)	11.77 (9.73-13.81)		F1, 145 = 33.70, P < .001
Injecting past 30 d (self-report)a	4 wk	37 (23-51)	21 (10-32)		3.54 (1.27-9.87) ${\mathrm{\chi }}_1^2$ = 6.00, P = .01
	8 wk	26 (12-40)	13 (4-22)
	12 wk	33 (18-48)	16 (6-26)
Months 6, 9, and 12
Any opioid use past month (self-report)c	6 mo	63 (49-77)	72 (59-85)		1.34 (0.70-2.57) ${\mathrm{\chi }}_1^2$ = 0.80, P = .37
	9 mo	70 (56-84)	53 (38-68)
	12 mo	72 (58-86)	53 (39-67)
Any alcohol use past month (self-report)	6 mo	46 (31-61)	37 (23-51)		1.30 (0.67-2.53) ${\mathrm{\chi }}_1^2$ = 0.60, P = .44
	9 mo	43 (28-58)	36 (22-50)
	12 mo	47 (32-62)	43 (29-57)
Any marijuana use past month (self-report)a	6 mo	30 (16-44)	24 (11-37)		1.33 (0.55-3.18) ${\mathrm{\chi }}_1^2$ = 0.39, P = .53
	9 mo	27 (14-40)	22 (10-34)
	12 mo	23 (10-36)	22 (10-34)
Any cocaine use past month (self-report)a	6 mo	20 (8-32)	11 (2-20)		3.84 (1.47-10.02) ${\mathrm{\chi }}_1^2$ = 7.45, P = .006
	9 mo	30 (16-44)	7 (0-15)
	12 mo	30 (16-44)	18 (7-29)
Injecting past 30 d (self-report)	6 mo	26 (13-39)	37 (23-51)		1.60 (0.71-3.60) ${\mathrm{\chi }}_1^2$ = 1.23, P = .23
	9 mo	35 (21-49)	20 (8-32)
	12 mo	28 (14-42)	18 (7-29)
In addiction treatment	6 mo	37 (23-51)	45 (30-60)		0.61 (0.35-1.09) ${\mathrm{\chi }}_1^2$ = 2.67, P = .10
	9 mo	31 (17-45)	44 (29-59)
	12 mo	40 (25-55)	53 (39-67)

Abbreviations: CI, confidence interval; GEE, general estimating equation; OR, odds ratio.

^aMantel-Haenszel analysis stratifying by site for binary outcome of use across 12 weeks. General estimating equation models failed to converge.

^bF test from analysis-of-covariance model.

^cSignificant group × time interaction, ${\mathrm{\chi }}_2^2$ = 6.99, P = .03; groups differed significantly at month 12.