The low-threshold methadone maintenance treatment (MMT)
programme in Hong Kong has been in place for about 40 years. Assessment of
the participation pattern of methadone users may inform future programme
development to achieve effective harm reduction.
Longitudinal clinical data of methadone users who first registered
for MMT in the year 2008 in Hong Kong were retrieved after ethical and
institutional approval. Participation pattern of this cohort was evaluated by
examining users’ frequency of attendance and then the overall retention rate. A
subgroup of consistent users who remained on treatment in 2012 and/or 2013 was
analysed. Comparison was made between high- and low-frequency users, and among
high/moderate and low consistency users, to test their correlations with
socio-demographics and social connectivity.
The cohort of methadone users registering in the year 2008
was composed of 351 persons, 77 % of whom were ethnic Chinese, with a
median age of 34 and the duration of heroin dependency of 6 years. The
participation pattern of methadone users was highly variable, with a 6-year
retention rate of 38 %. Discontinuations or 'breaks' of >28 days
had occurred in 212 (60 %) methadone users. About one third (n = 117) were
high-frequency users who had attended more than twice a week for at least
90 % of their treatment periods. The dosages received by high-frequency
users were generally higher. Of those continuing on treatment in the fifth
and/or sixth year (n = 185),
30 (16 %), 29 (16 %) and 126 (68 %) gave a high, moderate and
low level of consistency as defined by the lengths of breaks. High/moderate
consistency users had a longer history of heroin use and a higher degree of
connectivity with other users by social network analysis.
Despite the variability of frequency and consistency of
attendance of drug users enrolling in the low-threshold MMT programme in Hong
Kong, a consistent pattern could be seen in the proportional distribution of
dosage and participation efforts. Whereas an adequate dosage was a potential
predictor of optimal frequency of attendance, demographics and connectivity had
varied between continued users with different levels of consistency.
Table 1
General characteristics of methadone treatment users first admitted to the programme in 2008 (n = 351)
| No. | % |
|---|
| Median | IQR |
|---|
| Socio-demographics at first admission | | |
| Male | 266 | 76 % |
| HKID holdera | 267 | 76 % |
| Ethnic Chinese | 269 | 77 % |
| Age (years) | 34 | 28–40 |
| History of narcotic use (years) | 8 | 2–14 |
| History of injection (years) | 0 | 0–1 |
| Methadone clinic attendance pattern | | |
| Proportion attending >2/week during treatment period | | |
| <50 % | 65 | 19 % |
| 50–89 % | 164 | 47 % |
| ≥90 % | 122 | 35 % |
| Timing of attendance | | |
| Morning | 60 | 17 % |
| Afternoon | 100 | 28 % |
| Evening | 253 | 72 % |
| No. of clinics visited | 2 | 1–3 |
| Longest break (months) (n = 321) | 5 | 1–15 |
| Methadone treatment received | | |
| Completion of detoxification (n = 20) | 6 | 30 % |
| Mode dose (mg) | 40 | 30–50 |
| Dosage per day (mg) | 6 | 1–21 |
| Connectivity with clinic and among users | | |
| Connected in social networkb | 168 | 48 % |
| Degreec | 0 | 0–2 |
| Attendance at the nearest clinic (n = 134) | 94 | 70 % |
| Same residing and clinic district (n = 322) | 191 | 59 % |
| Distance (m) from home to frequently visited clinic (n = 134) | 609 | 264–1470 |
| Shortest distance (m) from home to clinic (n = 134) | 459 | 237–767 |
IQR interquartile range
aHKID holder refers to a person who is permitted to stay in Hong Kong for more than 180 days with the exclusion of visitors
bUsers who have at least one connection with any other users with F-score not less than 0.1
cThe number of connections with other users with F-score not less than 0.1
Below: Longitudinal pattern of attendance status of methadone users admitted in 2008 (n = 351). Discontinued users had discontinued methadone treatment for >28 days (‘break’), including those who did not return (defaulted). Readmitted users refer to those who returned to the MMT programme after a 28-day break. Active users of the year had attended at least once in the respective year
Below: Longitudinal pattern of weekly attendance frequency of methadone users in the cohort. The attendances were classified by the number of days per week, from once daily to once weekly
Below: Longitudinal pattern of monthly prescribed doses of methadone users in the cohort. Prescribed dosages were categorised into eight groups: ≥70, 60–69, 50–59, 40–49, 30–39, 20–29, 10–19, and <10 mg
Jockey Club
School of Public Health and Primary Care, The Chinese University of Hong Kong,
Shatin, Hong Kong
Stanley Ho Centre
for Emerging Infectious Diseases, The Chinese University of Hong Kong, Shatin,
Hong Kong
