Participation dynamics of a cohort of drug users in a low-threshold methadone treatment programme

Table 2 Comparison of methadone users by frequency of clinic visits (n = 345)

	Low frequency (n = 228)		High frequency^a (n = 117)		Test
	No.	%	No.	%	OR	95 % CI	p value
	Median	IQR	Median	IQR	Mann-Whitney U		p value
Socio-demographics at baseline
Male	169	74 %	94	80 %	1.427	0.83–2.46	0.20
Chinese	186	82 %	77	66 %	0.44	0.26–0.72	0.001*
HKID holder^b	162	71 %	100	86 %	2.40	1.33–4.32	0.003*
Age (years)	33	28–39	35	28–41	12,066		0.15
Aged >35	87	38 %	58	50 %	1.59	1.02–2.50	0.04*
Years of narcotic use	9	3–14	7	2–15	12,643		0.43
Methadone treatment dosage
Mode dosage (mg)	40	30–40	40	30–63	10,953		0.01*
Highest dose (mg)	50	35–75	65	50–80	10,154		<0.001*
Highest dose ≥80mg	49	22 %	42	36 %	2.05	1.25–3.35	0.004*
Lowest dose (mg)	20	10–30	15	10–25	11,385		0.02*
Lowest dose <20 mg	91	40 %	62	53 %	1.70	1.08–2.66	0.02*
Dose range (mg)	35	15–52	50	28–64	9549		<0.001*
Dose range >40 mg	95	42 %	77	66 %	2.70	1.70–4.29	<0.001*
Mean dose (mg)	37	29–48	40	31–56	11,044		0.01*
Median dose (mg)	40	30–48	40	30–60	11,117		0.01*
Proportion of days with dose <20 mg	0 %	0–4 %	0 %	0–7 %	11,865		0.07
Proportion of days with dose >40 mg	17 %	0–65 %	41 %	7–78 %	9996		<0.001*

OR odds ratio, 95 % CI 95 % confidence interval, IQR interquartile range
*p < 0.05
^aHigh frequency refers to attendance >2 times/week for >90 % of period of observation
^bHKID holder refers to a person who is permitted to stay in Hong Kong for more than 180 days excluding visitors

ISSN: 1477-7517