Table 2.

History of drug use of the particiants (n 187)

	OST (n 97)		Rehabilitation (n 90)		P-value	Total (n 187)
	N	%	N	%		N	%
Type of drug previously used
Drug use only	34	35⋅1	57	63⋅3	<0⋅001*	91	48⋅7
Drug injection only	1	1⋅0	1	1⋅1		2	1⋅1
Drug use and injection	62	63⋅9	31	34⋅4		93	49⋅7
No response	0	0⋅0	1	1⋅1		1	0⋅5
Frequency of drug previously used or injected
Up to three times daily	85	87⋅6	64	71⋅1	0⋅034*	149	79⋅7
Once or more daily	9	9⋅3	17	18⋅9		26	13⋅9
Once or more weekly	3	3⋅1	6	6⋅7		9	4⋅8
Does not know or remember	0	0⋅0	1	1⋅1		1	0⋅5
No response	0	0⋅0	2	2⋅2		2	1⋅1
Previous treatment
None	37	38⋅1	49	54⋅4	<0⋅001*	86	46⋅0
OST	6	6⋅2	6	6⋅7		12	6⋅4
Rehabilitation	22	22⋅7	28	31⋅1		50	26⋅7
Rehabilitation and OST	10	10⋅3	4	4⋅4		14	7⋅5
Hospital detoxification	18	18⋅6	2	2⋅2		20	10⋅7
Hospital detoxification and rehabilitation	4	4⋅1	0	0⋅0		4	2⋅1
No response	0	0⋅0	1	1⋅1		1	0⋅5
Other addiction
None	90	92⋅8	54	60⋅0	<0⋅001*	144	77⋅0
Alcohol	1	1⋅0	29	32⋅2		30	16⋅0
Other	6	6⋅2	7	7⋅8		13	7⋅0
	Mean	sd	Mean	sd		Mean	sd
Duration of drug use (years)	11⋅4	7⋅2	10⋅9	7⋅3	0⋅632	11⋅2	7⋅2
Duration of drug injection (years) (among those who reported drug injection)	7⋅3	6⋅3	8⋅0	5⋅6	0⋅469	7⋅5	6⋅1
Age at first drug use and/or injection (years)	18⋅3	6⋅7	16⋅3	4⋅6	0⋅006**	17⋅4	5⋅9
Number of previous treatment attempts	3⋅6	4⋅9	2⋅0	2⋅3	0⋅580	3⋅1	4⋅3
Treatment duration (months)	31⋅0	25⋅0	5⋅7	5⋅3	0⋅000**	19⋅2	23⋅0

OST, opioid substitution treatment.

^*P < 0⋅05 using independent samples t test.

^**P < 0⋅05 using Mann–Whitney U test.