NDARC Technical Report No. 155 (2003)
Evidence of the effectiveness of methadone maintenance treatment (MMT) in reducing heroin injection and HIV infection among injecting drug users (IDUs) in community settings has been well documented (Ward et al, 1998). However, many IDUs spend time in prison where approximately half continue to inject and typically share syringes (Butler et al, 1997). Yet few countries operate methadone maintenance programs for IDUs in prison.
This report documents a randomised controlled study of the NSW prison methadone program. Over 923 inmates were screened for suitability for participation in the trial. Of these, 593 were suitable and 382 agreed to take part in the study. The 382 subjects were interviewed, asked to provide a finger prick blood sample and a hair sample at recruitment and four months later. The blood samples were tested for hepatitis C (HCV) and HIV antibodies. The hair samples were tested for the presence of morphine.
Baseline characteristics: At baseline, subjects in both groups were comparable on all key demographic characteristics, prison histories, injecting drug use and sharing of injecting equipment in prison and in the community. Both groups had the same mean age (27 years), mean age first imprisoned (20 years), had been imprisoned a mean four (treated) and five (control) times, started injecting at mean age 17 years, and commenced daily injecting at mean age 19 (treated) and 18 (control) years. A quarter of both groups were Aboriginal or Torres Strait Islander (22%, 25%). Median length of current sentence was 1.4 years in both the treated (range 0.3-18) and control (range 0.2-21) group. The treated group was significantly more likely to report having shared syringes at some time in the community (76% vs 64%) while comparable proportions of both groups who had injected in prison reported sharing syringes (92%, 87%).
Drug use: Virtually all inmates reported injecting in the month before they entered prison (98% treated, 93% control). The most common drug injected prior to prison entry was heroin (96% treated, 90% control) followed by amphetamine (40%, 40%), cocaine (34%, 35%) and illicitly obtained methadone (26%, 23%). Most inmates in the treated group (69%) and the control group (74%) who had been in prison at least one month before being recruited into the study reported injecting heroin in prison.
Self reported HIV, HCV and HBV prevalence: No-one reported being HIV positive at entry to the study (it should be noted that this was an exclusion criterion for the study). Almost two thirds of treated (64%) and control (63%) subjects reported a previous positive hepatitis C result while one fifth (22%, 19%) of treated and control subjects reported positive hepatitis B (HBV) results. Approximately half of both groups reported having been vaccinated against HBV (49%, 48%).
HIV and HCV seroprevalence: Finger prick blood samples were assayed using an algorithm that has high correlation with assays of venous blood samples (NCCLS, 1998). HIV antibody was detected using Genetic Systems HIV-1 ELISA tests. HCV antibody was detected using a modified third generation enzyme immunoassay (Abbott HCV 3.0, Chicago II). The blood test results revealed 76% of treated and 72% of control subjects had antibodies to hepatitis C. No blood spot samples test positive for HIV.
Hair tests: Quantitative results for hair analysis (nanograms per mg of hair) were analysed. Hair samples were tested for morphine, the metabolite of heroin in the body, by Tricho- Tech Limited, Wales, UK. At baseline, one cm of hair cut from the root was analysed for morphine to assess heroin use in the previous month. The prevalence of morphine positive samples was 82% for the treated group and 83% for controls.
Follow up: The aim was to re- interview after a period of four months. Of the 382 subjects recruited into the trial, follow-up interviews were completed for 313 (82%). The rest were unavailable for follow up because they had been released from prison, declined to be re- interviewed or were incapable. Of the 162 (85%) treated and 152 (80%) control subjects who were re- interviewed, approximately one fifth (20%, 18%) of each group had been released and re-incarcerated between interviews and were excluded from main analysis. As the aim of the study was to assess the impact of methadone maintenance treatment on heroin use, syringe sharing and the prevention of blood borne viral infection (BBVI) in prison, only the 253 subjects who received a second interview and who had remained in prison are included in the current analysis. Therefore 129 (68%) of treated and 124 (65%) of control subjects who had been in continuous custody were included in the analysis for the purposes this report. The mean time period between interviews was 5.2 months for treated and 4.5 months for control subjects.
Drug use: Self- reported use of any illicit drug between interviews remained high at in both the treated and control group. At follow up, a three cm segment of hair was cut from the root, divided into three one cm sections and analysed for morphine to assess heroin use in each of the three months preceding the follow up interview. Hair samples reflecting the first month after recruitment were not tested. This month allowed inmates on methadone to reach an adequate dose (eg 60mg). When determined by both hair morphine concentration and self report, heroin use was significantly lower in the treated group at month two, three and four of follow up compared to the control group. Treated subjects also reported a significantly lower mean number of heroin injections in each month of follow up compared to controls.
Needle and syringe sharing: Treated subjects reported significantly less needle and syringe sharing at follow up compared to control subjects. There was no difference in the median number of sharing partners reported by treated compared to control subjects.
Seroconversion: Four subjects in both groups seroconverted to HCV. No one seroconverted to HIV.
Sexual risk behaviour: One ethics committee precluded questions about sexual activity from the first interview. However sexually contact with others was rarely report at follow up (2% treatment, 2% control) and no sexual behaviour was reported with other inmates.
Conclusion: The study demonstrated that it is possible to conduct a randomised control trial of a prison methadone program. The groups were comparable at baseline. At follow up, the treatment group had benefited from being on methadone as they reported less heroin use, less injecting and less syringe sharing. Combined results from hair analysis and self report also showed less heroin use among the treated group. There were equal numbers of HCV seroconversions and no HIV seroconversions.
Citation: Dolan, K., Shearer, J., White, B. and Wodak, A. (2003) A randomised controlled trial of methadone maintenance treatment in NSW prisons, Sydney: National Drug and Alcohol Research Centre.