TABLE 4.

Moderators of failure to initiate study medication among patients randomly assigned to extended-release naltrexone (N=283) or buprenorphine-naloxone (N=287)

	Treatment-by-Moderator Interactiona			Treatment Effect		Estimated Initiation Failure Ratec (%)
Moderator Variable	F	df	p	Odds Ratiob	95% CI	Extended-Release Naltrexone	Buprenorphine-Naloxone
p<0.001
Pain discomfort, moderate or extreme	13.08	1, 559	<0.001
None				2.18	1.04, 4.60	16.42	8.25
Moderate or extreme				23.68	8.21, 68.34	32.44	1.99
Current probation or parole	12.20	1, 558	<0.001
No				12.86	5.96, 27.76	27.04	2.80
Yes	7.13	2, 556	<0.001	1.25	0.43, 3.61	17.39	14.39
Prefer to receive buprenorphine-naloxone	7.13	2, 556	<0.001
Disagree				1.43	0.59, 3.44	17.50	12.94
Neutral				9.22	3.35, 25.39	23.62	3.25
Agree				55.28	7.27, 420.15	33.01	0.88
Timing of randomizationd	13.93	1, 559	<0.001
Early				47.79	11.15, 204.89	41.30	1.45
Late				2.26	1.15, 4.45	17.03	8.33
0.001≤p<0.05
Hispanic ethnicity	3.98	1, 559	0.047
Not Hispanic				4.88	2.68, 8.89	22.95	5.75
Hispanic				44.49	5.49, 360.56	37.00	1.30
Current cannabis use	4.50	1, 559	0.034
No				4.09	2.05, 8.19	27.04	8.30
Yes				18.49	5.52, 61.97	24.32	1.71
Any past treatment successful	4.91	1, 559	0.027
No				4.11	2.13, 7.93	23.49	6.95
Yes				25.03	5.81, 107.87	27.87	1.52
Past methadone or buprenorphine treatment successful	4.16	1, 559	0.042
No				4.52	2.39, 8.55	25.02	6.87
Yes				40.74	5.40, 307.42	25.75	0.84
Anxiety or depression levels, moderate or extreme	4.38	1, 559	0.037
None				3.15	1.35, 7.38	21.79	8.12
Moderate or extreme				10.86	4.93, 23.92	27.21	3.33
Any friends or family with heroin or other opioid use problems	4.62	1, 554	0.032
No				15.88	5.33, 47.27	30.65	2.71
Yes				3.89	1.97, 7.68	21.81	6.69
Prefer to receive extended-release naltrexone:	5.61	2, 556	0.004
Disagree				28.59	3.65, 224.22	30.23	1.49
Neutral				24.61	5.71, 106.01	23.57	1.24
Agree				2.31	1.07, 4.98	24.54	12.35
Typical discomfort level during past episodes of opioid withdrawal	7.97	1, 557	0.005
0–7 (0 = none; 1=little discomfort)				3.08	1.48, 6.40	19.65	7.36
8–10 (10=almost unbearable)				19.73	6.80, 57.26	31.64	2.29

^aLogistic regression was conducted, with a p value <0.001 considered significant.

^bOdds ratios >1.0 favored buprenorphine-naloxone; odds ratios <1.0 favored extended-release naltrexone.

^cValues are model estimated.

^dEarly randomization occurred within 3 days of the last opioid exposure, illicit or prescribed; late randomization occurred more than 3 days after the last opioid exposure.