Table 3.

Factors associated with opioid relapse among methadone maintenance patients

Variables	Univariate logistic regression		Multivariate logistic regression
	OR (95% CI)	p value	aOR (95% CI)	p value
1. Sex (ref: female)
Male	0.60 (0.13–2.87)	0.521
2. Age (years old)	0.98 (0.95–1.00)	0.037
3. Residence (ref: Metropolitan)
Mountainous	4.03 (2.14–7.59)	< 0.001	3.63 (1.90–7.46)	< 0.001
4. Education level (ref: College, university, or higher)
Primary school or lower	1.10 (0.38–3.22)	0.856
Secondary school	1.57 (0.63–3.88)	0.331
High school	1.25 (0.49–3.17)	0.638
5. Occupation type (ref: full-time)
No	1.07 (0.54–2.12)	0.844
Seasonal or part-time	1.65 (0.94–2.90)	0.082
6. Career (ref: Farmer)
Not working	0.56 (0.30–1.07)	0.079
Freelancer	0.89 (0.51–1.56)	0.682
Trader	0.43 (0.14–1.31)	0.139
Others	0.20 (0.07–0.61)	0.004
7. Patient’s income per month (million VND)	0.99 (0.92–1.06)	0.749
8. Family’s income per month (million VND)	0.95 (0.91–1.00)	0.0504
9. Number of family members living with the patient	0.76 (0.64–0.92)	0.003	0.69 (0.55–0.85)	< 0.001
10. Number of close friends/relatives	0.75 (0.66–0.86)	< 0.001
11. Social support score	0.99 (0.98–0.99)	< 0.001
12. Initial drug use age	0.94 (0.90–0.98)	0.004
13. Duration of drug use in the past (year)	1.06 (1.04–1.09)	< 0.001	1.06 (1.03–1.09)	< 0.001
14. The number of previous treatment	0.94 (0.81–1.08)	0.378
15. Daily methadone dose (mg)	0.995 (0.99–1.00)	0.064
16. Treatment time (year)	0.83 (0.76–0.90)	< 0.001	0.80 (0.73–0.87)	< 0.001
17. Adherence (ref: No)
Yes	0.38 (0.24–0.60)	< 0.001	0.38 (0.23–0.64)	< 0.001
18. Comorbidity	0.73 (0.46–1.14)	0.168
19. ART (Ref: No)
Yes	0.71 (0.31–1.61)	0.414

Exchange rate: 1 million Vietnam dongs (VND) = 42.373 US dollars

OR odds ratio, aOR adjusted odds ratio, CI confidence interval, ref reference