This page refers to the current evidence on the effectiveness of the available harm reduction options for opioid injectors. Information on the methodology used and the definition of terms can be found on the methodology page.
Date of last update: 27.03.2013 Next update: May 2014
What's new: Updated information on the effectiveness of OST and NSP on HIV and HCV related outcomes as well as on Naloxone to prevent overdose mortality.
(1): the measure from the RCT is not statistically significant, nevertheless the evidence when considered together with the results of the observational studies, is significant.
The combination of OST and NSP has been found to be effective in a meta-analysis of observational studies (Turner et al., 2011) (5 studies, N= 919) in:
Based on one systematic review and one meta-analysis of four cohort studies (Kerr et al., 2007, Hedrich, 2004, cited in EMCDDA, 2010) it was concluded that there is tentative evidence that DCR use is associated with:
Based on one narrative (Tilson et al., 2007, cited in EMCDDA, 2010) and one systematic review (Wodak, 2004, cited in EMCDDA, 2010) without meta-analysis, there is tentative evidence to support the effectiveness of pharmacy access to needles/syringes — in addition to dedicated NSPs — in:
Two narrative reviews (Tilson et al., 2007 and Gibson et al., 2001, cited in EMCDDA, 2010) and one systematic review (Wodak, 2004, cited in EMCDDA, 2010) of more than 100 studies, without meta-analysis, concluded that there is tentative evidence to support the effectiveness of NSPs in:
Opioid substitution treatment was found sufficiently supported by evidence in a synthesis of 4 narrative reviews (Malta et al.,2008; WHO, 2007b, Tilson et al., 2007, Lucas et al., 2006, cited in EMCDDA - ECDC 2011) in:
A systematic review (Wright and Tompkins, 2006, cited in EMCDDA, 2010) without meta-analysis of 18 observational studies (N= 18332) conducted between 1993 and 2002 in 10 different countries over three continents found very limited evidence that OST can achieve:
Based on one narrative review (Stallwitz and Stover, 2007, cited in EMCDDA, 2010) that did not pool results from 4 observational studies and one RCT there is tentative evidence to support the effectiveness of prison-based OST in:
reducing injecting risk behaviour among IDUs by decreasing frequency of injection of heroin and other opiate use.
No interventions met these criteria.
Based on one systematic review and one meta-analysis of four cohort studies (Kerr et al. 2007, Hedrich, 2004, cited in EMCDDA, 2010) it was concluded that there is not enough evidence to support or discount the effect of DCRs on:
Naloxone training and prescription was analyzed in a narrative review including 6 articles on Naloxone distribution programs (Baca, 2005). Although all the studies proved a potential for reducing mortality, they often conclude that more research is needed.
Two narrative reviews (Dolan et al., 2003; Stöver, 2003, cited in EMCDDA, 2010) enclosed in the EMCDDA HR monograph, concluded that there is insufficient evidence to either support or discount the effectiveness of prison NSPs in:
Opioid Substitution Treatment (OST) to increase compliance to HCV treatment was considered not possible to assess due to the lack of ad-hoc studies in a synthesis based on a narrative review (Hellard et al., 2009, cited in EMCDDA - ECDC 2011) including 30 observational studies with a total number of patients superior to 4,000.
Opioid Substitution Treatment (OST) association to HCV treatment virological response was considered still unknown in a synthesis based on a narrative review (Hellard et al., 2009, cited in EMCDDA - ECDC 2011) including 30 observational studies with a total number of patients superior to 4,000.
Data from one study in a jurisdiction with low HIV prevalence found no difference in:
Two narrative reviews (Coyle et al., 1998; Needle et al., 2005) comprising respectively 36 and 40 observational studies but not without performing meta-analysis, concluded that outreach and education intervention are effective in:
Four narrative reviews (Gibson et al., 2001; Tilson et al., 2007; Wodak, 2004; Wright et al., 2006, cited in EMCDDA, 2010) concluded that there is insufficient evidence to either support or discount the effectiveness of NSPs in:
No interventions met these criteria.
Below you can find definitions and further explanation for some of the terms used in this section of the Best practice portal. A more general glossary for the best practice portal is also available.
A type of prevention intervention which aims to they aim to modify inner qualities (personality traits such as self-esteem and self-efficacy, and motivational aspects such as the intention to use drugs).
Before-after (BA) study design
Interventions for which precise measures of the effects in favour of the type of intervention were found in systematic reviews of relevant studies. An intervention ranked as ‘beneficial’ is suitable for most patients/contexts. See the relevant module methodology page for further information.
Controlled before-after (CBA) study design. UCBA stands for Uncontrolled before-after study design.
Cognitive behavioral therapy is an individual based intervention occurring in three stages. Phase 1 is aimed at determining and prioritizing the patient’s problems and constructing the treatment contract. Phase 2 is aimed at increasing coping competence and reducing risky behaviors. Phase 3 focuses on relapse prevention. Each session is administered once per week over a period of 4-6 months with 60- to 90-minute sessions (Beck AT, Wright FW, Newman CF, Liese B. Cognitive Therapy of substance abuse. New York: Guilford Press, 1993).
Controlled clinical trials (CCT)
A cohort study is a type of observational study that follows a group of people (i.e. a cohort) over time. In a prospective cohort study, the cohort is formed and then followed over time. In a retrospective cohort study, data is gathered for a cohort that was formed sometime in the past.
The Confidence Interval (CI) is a measure of the precision (or uncertainty) of study results. It is the interval that most likely includes the true value of the parameter we are calculating, where 'most likely' is taken by common usage to be a 95% probability. Thus the current expression of '95 % CI'. A wide CI indicates less precise estimates of effect and vice versa.
Current population survey (CPS)
A cross-sectional study is a study employing a single point of data collection for each participant or system being studied.They are usually conducted to estimate the prevalence of the outcome of interest for a given population at a given point in time.
Interventions that gave negative results if compared with a standard intervention or no intervention, for example. See the relevant module methodology page for further information.
Additional information for prevention
For ethical reasons this category in prevention should be considered as interventions with negative and undesired (iatrogenic) effect.
Individual psychotherapy is a standard individual treatment based on counseling and motivational interviewing and focused on substance use triggers and strategies for relapse prevention. It includes elements of cognitive-behavioral therapy (CBT).
Intermittent time series design (CPS)
Knowledge-focused prevention intervention
A type of prevention intervention which aims to to enhance knowledge of drugs, and drug effects, and consequences.
Interventions that were shown to have limited measures of effect, that are likely to be effective but for which evidence is limited. An intervention ranked as ‘likely to be beneficial’ is suitable for most contexts/patients, with some discretion. See the relevant module methodology page for further information.
The Number Needed to Treat (NNT)indicates the number of patients that needs to be treated to obtain one respondent patient. Numerically the NNT is the reciprocal of the difference between the proportion of events in the experimental and the comparison group (absolute risk reduction). Taking into consideration that the ideal NNT would be 1 (the unreal situation in which every single patient succeeded) it is easily understood that a NNT value close to 3 or 4 would be very good.
The Adjusted Odds Ratio is a way of comparing whether the probability of a certain event is the same between two groups, yet they are calculated adjusting for or controlling for other possible contributions from other variables (tipically demographic variables) in the model. An AOR equal to 1 implies that the the event is equally probable in both groups. An AOR greater than 1 implies that the event is more likely in the first group. An AOR less than 1 implies that the event is less likely in the first group.
The Odds Ratio is a way of comparing whether the probability of a certain event is the same between two groups. Like the Relative Risk, an OR equal to 1 implies that the the event is equally probable in both groups. A OR greater than 1 implies that the event is more likely in the first group. A OR less than 1 implies that the event is less likely in the first group. In medical research, the odds ratio is commonly used for case-control studies, as odds, but not probabilities, are usually estimated. Relative risk is used in randomized controlled trials and cohort studies.
A p-value is a measure of how much evidence we have against the null hypothesis. The null hypothesis represents the hypothesis of no change or no effect. The smaller the p-value, the more evidence we have against the null hypothesis thus it is more likely that our sample result is true. Traditionally, researchers will reject a null hypothesis if the p-value is less than 0.05.
Randomised controlled trial (RCT)
The Relative Risk (RR) is used to compare the risk in the two different groups of people, i.e. treated and control groups to see if belonging to one group or another increases or decreases the risk of developing certain outcomes. This measure of effect will tell us the number of times an outcome is more likely (RR > 1) or less likely (RR < 1) to happen in the treatment group compared with the control group.
Interventions that obtained measures of effects in favour of the intervention, but that showed some limitations or unintended effects that need to be assessed before providing them. See the relevant module methodology page for further information.
Interventions for which there are not enough studies or where available studies are of low quality (with few patients or with uncertain methodological rigour), making it difficult to assess if they are effective or not. Interventions for which more research should be undertaken are also grouped in this category.
Additional information for prevention
For prevention interventions, this is also known as 'zero effect'.
A type of prevention intervention which aims to enhance students’ abilities in generic skills, refusal skills and safety skills.
The Standardised Mean Difference (SMD) is the difference in means divided by a standard deviation. Note that it is not the standard error of the difference in means (a common confusion). The standardized mean difference has the important property that its value does not depend on the measurement scale. It may be useful if there are several trials assessing the same outcome, but using different scales.
The z-score (aka, a standard score) indicates how many standard deviations an element is from the mean of the population.
Infectious diseases such as HIV and hepatitis B and C are among the most serious health consequences of drug use. The HIV epidemic among injecting drug users continues to develop differently across Europe. In the countries of the European Union, the rates of reported newly diagnosed cases of HIV infection in injecting drug users are mostly at stable and low levels, or in decline. However, in many of the eastern countries, rates have increased.
As well as HIV, hepatitis B and C, other infectious diseases, such as hepatitis A, sexually transmitted diseases (see below), tuberculosis, tetanus, botulism and human T-lymphotropic virus may disproportionately affect drug users.
Sexually transmitted infections (STI) are a major global cause of acute illness, infertility, long-term disability and death, with severe medical and psychological consequences for millions of men, women and infants. Injecting drug users’ perception of sexual risk means that they are more at risk of developing STI.
Drug-related mortality includes deaths that are directly caused by the pharmacological action of one or several substances (drug-induced deaths) and deaths that are indirectly caused by the use of drugs, often with other concurrent factors (e.g. accidents). Known causes of deaths include acute toxicity, traffic accidents in particular when combined with alcohol, violence, suicide among already vulnerable people, or chronic conditions due to repeated use (e.g. cardiovascular problems in cocaine users).
Among Europeans aged 15–39 years, drug overdose accounted for 4 % of all deaths, in 2008. An overdose can occur if someone takes a larger dose of a drug than the body can tolerate. Overdoses can occur accidentally or deliberately, and they can be fatal or not fatal.
The risk of overdose with illicit drugs is particularly high when the drug content is not known. The risks are increased if the person has recently been through detoxification.
Public nuisance is identified defined as offences that affect the local community as a whole rather than the individuals. Drug-related public nuisance actually refers to a very wide range of ‘deviant behaviours Some activities are minor in their effect; others, can be perceived as causing major distress.
Unsafe injecting practices include sharing of needles/syringes and other injection materials and there is a strong association between such practices and blood-borne infectious diseases such as HIV, HBV and HCV.
Infections of injection sites can be common among injecting drug users and these may include: cellulitis, abcesses, skin ulcers, necrotising fasciitis, septic thrombophlebitis, and miscellaneous infections.
It has been shown that the sexual transmission of HIV among IDUs remains a significant concern, particularly in areas in which HIV or other STI epidemics are established, and where drug use intersects with sex work.
By the end of 2007, the incidence of reported HIV infection among injecting drug users appears to have remained low in most countries of the European Union, and the overall EU situation appears relatively positive in a global context.
Viral hepatitis and, in particular, infection caused by hepatitis C virus (HCV), is more highly prevalent than HIV in injecting drug users across Europe.
Population mortality rates due to drug-induced death vary widely between countries, ranging from 3 to over 85 deaths per million population aged 15–64 years, with an average of 22 deaths per million in Europe.
Needle and syringe programmes (NSPs) are interventions which provide sterile needles/syringes and other injecting equipment to injecting drug users. Delivery is diverse and can include a ‘primary’ fixed site, mobile and/or outreach services and ‘secondary’ access via community pharmacies, other health services and/or vending machines. NSPs operate across all EU Member States.
Opioid substitution treatment is prescribed to dependent users to diminish the use and effects of illicit opiates. Community-based OST is available across all EU Member States and prison-based OST is officially available in the majority of Member States, although overall accessibility is limited.
DCRs offer a low-threshold environment to use pre-obtained drugs hygienically and to access targeted safer injecting advice and intervention in case of overdose. DCRs have been operating in Europe for more than 25 years and are available in 59 cities across Germany, Luxembourg, the Netherlands, Norway, Spain and Switzerland.
Peer naloxone distribution (PND) or ‘take-home naloxone’ programmes provide the antagonist drug, with training to IDUs and/or carers to improve their capacity for effective intervention at opioid-related overdose.
Outreach and education rely on peers and local health workers to identify IDUs and provide education on preventing HIV and other infections, and to serve as guides to health and social services. Outreach workers may distribute information on HIV/AIDS, bleach kits for disinfecting injection equipment, and condoms.
While some programs are linked to needle and syringe exchanges or drug treatment clinics, outreach efforts often occur outside clinical settings and separate from other interventions.
Involves individuals actively seeking HIV testing and counselling at a facility that offers these services.