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This is a plain English summary of an original research article. The views expressed are those of the author(s) and reviewer(s) at the time of publication.
A combination of providing clean needles and syringes and offering safer oral therapy, such as methadone, reduced the predicted risk of becoming infected with hepatitis C virus by 71%. Providing both services to people who inject drugs was likely to be cost-effective and has the potential to be cost-saving in some parts of the UK, depending on the size of the local population of people who inject drugs and underlying rates of infection.
Current services are estimated to save up to £54 million in costs of treating hepatitis C infection. This is in addition to the savings made from reducing the incidence of HIV infections. This study suggests that if such programmes are decommissioned, the number of new hepatitis C infections would at least double.
This NIHR-funded study combines a review of international evidence with analysis of current usage data from three UK sites, and models the impact of withdrawing or increasing services. The evidence is based on observational studies and modelling so should be interpreted with caution. However, given the nature of the subject, it would be difficult to gather higher quality evidence.
Why was this study needed?
In 2015/16, nearly 150,000 adults seeking help for substance misuse were opiate dependent. About a quarter of those seeking help for opiates were currently injecting. Amongst those injecting almost half have hepatitis C - a virus that, if left untreated, can cause cirrhosis and liver failure. The risk of contracting this blood-borne virus increases with reuse of contaminated needles or syringes.
Key interventions to reduce infections are needle and syringe programmes which minimise the use of contaminated equipment, and opioid substitution therapy. Opioid substitutes are oral medications such as methadone, buprenorphine and naloxone which are usually given under supervision and provide a route to stopping or reducing the frequency of injecting.
Although there is good evidence that these interventions have an impact on the spread of HIV, there is little evidence of their impact on the incidence of hepatitis C. This study aimed to fill that knowledge gap, as well as assess costs and cost-effectiveness of these ‘harm reduction’ programmes.
What did this study do?
This research included a systematic review and meta-analysis of 28 studies reporting the effects of needle and syringe programmes and opioid substitution therapy on rates of new hepatitis C infection. The researchers also analysed data from eight surveys of a total of 14,734 people to calculate the risk of infection according to the level of exposure (how often people used the clean equipment or substitutes). Finally, data on the costs of needle and syringe programmes from three cities in the UK were collated for the financial year 2013-14. A mathematical model was used to estimate the effect on the spread of hepatitis C infection if interventions were withdrawn or increased, and to assess their cost-effectiveness.
Only five of the 28 studies in the review were from the UK, and the majority were observational studies, rated as low-quality evidence. Other limitations include the difficulty in measuring how often people swapped their injecting equipment.
What did it find?
- Oral substitutes reduced the risk of being infected with hepatitis C by 50% after taking into account numerous potential confounding factors (adjusted rate ratio [aRR] 0.50, 95% confidence interval [CI] 0.40 to 0.63); 12 studies, 6,234 participants). For example, this would reduce a base line rate of 20 new hepatitis C infections per 100 users per year to 10. In other words, 10 people would need to enrol in opioid substitution for a year for one case of hepatitis C to be prevented.
- According to European studies, mostly in the UK, when people used clean needles each time they injected (100% coverage) there was a 56% reduction in the risk of hepatitis C infection (RR 0.44, 95% CI 0.24 to 0.80; four studies, 3,994 participants). Modelling suggests that increasing the coverage of exchange programmes from existing low rates so that 80% of injections are with a clean needle/syringe, could decrease the number of new hepatitis C infections overall by 10 to 26% by 2031.
- A combination of high usage of exchange programmes and oral substitutes resulted in a 71% reduction in the risk of hepatitis C infection (RR 0.29, 95% CI 0.13 to 0.65; four studies, 3,360 participants).
- Costs of the exchange programmes vary around the UK, but are highly likely to be cost-effective at any willingness-to-pay threshold and were found to be cost-saving in some areas. It was estimated that maintaining current services could save up to £54 million in costs of treating hepatitis C. There was insufficient cost data to assess the cost-effectiveness of opioid substitution.
- The modelling suggests that removing either or both harm reduction schemes would lead to an increase in hepatitis C infections over the next 15 years. It predicted that removing opioid substitution (current coverage 81%) and needle exchange (current coverage 56%) from Bristol would increase annual hepatitis C infection incidence by 329% (95% credible interval 110% to 953%) by 2031, and at least double the number of new infections.
What does current guidance say on this issue?
NICE’s 2014 guideline on needle and syringe programmes recommends that a mix of services should be provided to meet local needs. These services should be coordinated so that testing for hepatitis B and C is available to everyone who uses a needle and syringe programme. It also says that services offering opioid substitution should make needles and syringes available to their service users.
What are the implications?
Needle and syringe exchanges and opioid substitution are likely to prevent considerable rates of hepatitis C infection in the UK, particularly when the services are offered together. Needle and syringe exchange appears to be cost-effective, especially if considering the health gains from preventing HIV transmission too. Although the evidence is from observational studies, and the extent of the benefit might uncertain, the nature of the topic makes it difficult to gather evidence in any other way and compared to the cost of treating the consequences of hepatitis later, seems good value.
NICE guidance already suggests that needles and syringes should be offered with opioid substitution. This study strengthens those recommendations and could inform future updates. Barriers preventing these services being offered together need to be examined.
Citation and Funding
Platt L, Sweeney S, Ward Z, et al. Assessing the impact and cost-effectiveness of needle and syringe provision and opioid substitution therapy on hepatitis C transmission among people who inject drugs in the UK: an analysis of pooled data sets and economic modelling. Public Health Res. 2017;5(5).
This project was funded by the National Institute for Health Research (NIHR) Public Health Research programme (project number 12/3070/13).
Bibliography
Health and Safety Executive. Hepatitis C virus (HCV). London: Health and Safety Executive.
NHS Choices. Hepatitis C. London: Department of Health; updated 2015.
NICE. Drug misuse in over 16s: opioid detoxification. CG52. London: National Institute for Health and Care Excellence; 2007.
NICE. Needle and syringe programmes. PH52. London: National Institute for Health and Care Excellence; 2014.
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