About 5–10% of people addicted to heroin who remain on oral methadone maintenance therapy fail to benefit and continue to inject heroin on a regular basis. There is emerging evidence to support the effectiveness of maintenance treatment with supervised medicinal heroin (diamorphine) as a second-line treatment for chronic heroin addiction. Researchers report cost-effectiveness data from the Randomised Injectable Opiate Treatment Trial (RIOTT) which compared supervised injectable heroin (n=43) or injectable methadone (n=42) with optimised oral methadone (n=42) for chronic refractory heroin addiction in patients not responding to current oral maintenance treatment, attending supervised injecting clinics in three sites across England (south London, Darlington and Brighton). Full economic data were available for 94.5% of the sample (n = 120). Most were men (n = 93, 73%), White (n = 122, 96%) and unemployed (n = 121, 95%), had spent time in prison (n = 93, 73%), and had a mean age of 37.2 years. The subjects had used opiates for a mean of 16.6 years, had injected drugs for a mean of 13.7 years and had received treatment for a mean of 9.8 years.
The primary clinical outcome was proportion of participants negative for street heroin in at least 50% of weekly random urine tests during weeks 14–26 (‘responders’). The economic outcome measure was quality-adjusted life-years (QALYs). Outcomes were assessed at baseline, 14 and 26 weeks after trial entry. The economic evaluation took a broad perspective, including all health and social services, plus the criminal justice sector. All unit costs were for the financial year 2007/08.
The following findings were reported:
• Total intervention costs over the 26-week follow-up were statistically significantly higher for the injectable heroin group (mean £8995 v. £4674 injectable methadone and £2596 oral methadone groups; p<0.0001)
• The total cost of other health, social services and criminal justice resources were similar across groups (injectable heroin £2632, injectable methadone £2745, oral methadone £2274), as were health and social services alone (injectable heroin £2190, injectable methadone £1865, oral methadone £2023).
• The cost of crimes committed varied considerably (injectable heroin £1782, injectable methadone £3526, oral methadone £10,962), however these differences were not statistically significant.
• Overall, including the cost of the interventions, other services and crimes, the oral methadone group was the most expensive (£15,805), followed by the injectable heroin (£13,410) and methadone (£10,945) groups. From the narrower NHS/personal social services perspective, injectable heroin was the most expensive (£11,186), followed by injectable methadone (£6539) and oral methadone (£4592).
• In intention-to-treat analysis, a higher proportion of participants in the injectable heroin group (72%) were classified as responders (negative for street heroin in 550% of urine tests in weeks 14–26) than those in the injectable and oral methadone groups (39% and 27% respectively). The difference was significant for injectable heroin v. oral methadone (odds ratio 7.42, 95% CI, 2.69–20.46, p<0.0001), but not for injectable v. oral methadone (1.74; 66–4.60, p= 0.264).
• Quality-adjusted life years over the follow-up, were also higher for the injectable heroin group (mean 0.27) than the injectable and oral methadone groups (mean 0.24 in both groups), but not significantly so (p= 0.8475).
• At a willingness to pay of £30 000, there is a 70% probability that injectable heroin is more cost-effective than oral methadone.
The researchers conclude that their findings “do not support the continuing provision of oral methadone maintenance treatment alone for chronic refractory heroin addiction, despite the relatively low treatment costs in comparison to injectable alternatives. However, policy makers will need to compensate clinics for providing a more expensive service that generates cost savings primarily for the criminal justice sector. The choice of which injectable treatment to provide is less clear.” They acknowledge limitations to their study such as the large cost differences between groups not reaching statistical levels of significance due to high levels of variance in the cost of crimes resulting from small numbers of prolific offenders; the reliance on self-reported levels of criminal activity; the relatively short follow-up which may not be long enough to capture the full economic implications in this chronic population, and the generalisability of the results to other populations who are treated successfully with conventional oral methadone maintenance. In addition, the results may not reflect standard clinical practice in relation to the oral methadone arm of the trial, which was optimised in a way that may not happen in all routine clinics.
Current NICE guidance supports use of oral formulations of methadone and buprenorphine (using flexible dosing regimens) as options for maintenance therapy in the management of opioid dependence.