The consequences of drug use and benefits of methadone maintenance therapy (MMT) were investigated in a random sample of Maori and non- Maori injecting drug users in Christchurch, Aotearoa New Zealand. Eighty- five injecting drug users (IDUs) who had been on MMT for a mean time of 57 months were interviewed and followed up over an average 18 month period.
Markov models were used to model cohorts of IDUs, changes in their health states and the effects of MMT and anti-viral therapy on morbidity and mortality. The savings in life from reductions in drug overdoses were used as the main outcome measure in cost-effectiveness analysis. Cost-utility and cost-benefit analysis were also used to provide additional information on the costs and outcomes of treatment. Comparisons were made between: (a) MMT alone; (b) MMT provided with conventional combination therapy for hepatitis C virus (HCV); and (c) MMT provided with anti-viral therapy with pegylated interferon.
The monetary costs of drug use and benefits of MMT were similar for Maori and non-Maori. However, Markov modelling indicated that MMT is associated with greater savings in life for Maori than for non-Maori. Further, Maori IDUs identified the main personal costs of drug use as being loss of their children and loss of marriage or partners.
Large reductions in use of opioids and benzodiazipines were reported at interview, compared with before starting MMT. The participants also reported large reductions in crime and stabilisation of their lifestyles. Improvements in the general health of IDUs om MMT were reported. However, 89% were positive for HCV infection, which was identified as the major physical health problem affecting IDUs in New Zealand. Few IDUs had received anti-viral therapy for HCV infections, despite having stabilised on MMT. This study investigated the benefits of providing anti-viral therapy for HCV to all patients meeting treatment criteria.
The cost-effectiveness of MMT alone was estimated at $25,397 per life year saved (LYS) for non- Maori men and $25,035 for non-Maori women IDUs (costs and benefits discounted at 3%). The incremental effects of providing anti-viral therapy for HCV to all eligible patients were to save extra years of life, as well as to involve additional costs. The net effect was that anti-viral therapy could be provided, at a similar level of cost-effectiveness, to all patients who meet HCV treatment criteria. Cost-effectiveness could be improved if IDUs could be stabilised on MMT five years earlier at an average age of 26 instead of the current age of 31 years. The cost-effectiveness of treatment with pegylated interferon was similar to that for conventional combination therapy because there were incremental savings in life as well as increased treatment costs.
Costs per LYS were estimated to be lower for Maori than for non-Maori, reflecting ethnic differences in mortality. Sensitivity analysis revealed that provision of MMT with anti-viral treatment remained cost-effective under varying assumptions of mortality, disease progression and compliance with treatment.
the main problems that were not improved during MMT were continuing use of tobacco and cannabis, low participation in paid employment, only three participants had received specific treatment for their HCV infections.
Cost-benefit analysis using a conservative approach showed a ratio of the benefits to the costs of MMT of 8:1. Benefits were demonstrated in terms of large reductions in crime. Benefit to cost ratios were similar for the different policy examined, as well as for both Maori and non-Maori IDUs.
| Identifer | oai:union.ndltd.org:ADTP/217527 |
| Date | January 2005 |
| Creators | Sheerin, Ian G, n/a |
| Publisher | University of Otago. Christchurch School of Medicine & Health Sciences |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | http://policy01.otago.ac.nz/policies/FMPro?-db=policies.fm&-format=viewpolicy.html&-lay=viewpolicy&-sortfield=Title&Type=Academic&-recid=33025&-find), Copyright Ian G Sheerin |
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