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Bulletin 7 August 2008
Adequate needle exchange helps prevent bacterial as well as viral infections
Bacterial infections at the injecting site are an everyday experience for drug injectors and a common (but not the only) cause of abscesses, pus-filled cavities resulting from inflammation. The consequences can include loss of limbs and death if the infection spreads. Findings from new US study suggest that needle exchanges which make adequate supplies of injecting equipment easily accessible not only prevent viral infections, but also prevent abscesses, relieving a major and expensive burden on health services. More restrictive policies are less effective and may end up costing health services more than they save.
Findings
Conducted in Eureka, California, the featured study analysed records from the area’s needle exchange and records of abscesses treated at local health centres from the start of 2002 to the end of February 2004. This period straddled the introduction in April 2003 of a more restrictive policy at the needle exchange. Walk-in one-for-one exchange combined with advice and health care was capped to a maximum of 100 needles per visit, for which appointments were now required. As a result the number of visits made to the exchange and the number of needles exchanged both fell, the latter from on average 3268 a week to 471. At the same time the average number of abscesses treated rose by six a week to just over 14.
These trends were closely and highly significantly related; the fewer needles exchanged or the fewer visits in any week, the greater the number of abscesses. Put the other way round, every extra 1000 needles exchanged or every extra eight visits were associated with one fewer abscess. The result was that the exchange’s saving of about $243 a week on injecting equipment was overshadowed by at least an extra $500 a week spent on treating abscesses. 
A survey of 62 former injectors recruited through local mutual aid meetings also found that the more needles they had exchanged per visit, the fewer abscesses they had suffered.
In Context 
About the study
Findings at this exchange might have been so clear cut because it served a rural area. Probably this offered few alternative sources of sterile equipment for injectors hit by the exchange’s change of policy and made it easier to identify the impact because the rise in abscesses would be clearly localised at neighbourhood health centres. Also, the change in policy was dramatic. The appointment regime seemed to cut visit numbers at the same time as the quantity cap limited per visit supplies, combining to cut supplies by 86%. The consequence was to expose a relationship between abscesses and the adequacy of needle exchange provision which might have remained hidden in other circumstances. Which elements of that provision were critical is unclear; probably (see below) both access to advice/health care and access to sterile equipment.
Though the analysis based on needle exchange and health service records seems convincing, the survey of former injectors is at best a weak reinforcement of the findings. In this brief report, the economic analysis – not planned in to the study from the start – is not described in detail and seems to have accounted only for equipment costs at the exchange. However, with serious abscesses often requiring several days inpatient care, the chances are strong that a preventive strategy based on adequate injecting equipment supply and frequent health checks/advice would net cost savings. 
Related studies
The mechanisms via which needle exchanges might help prevent abscesses include reducing use of potentially contaminated equipment, reducing the re-use of one’s own equipment, and improving injecting technique, particularly hygiene. There is evidence for all these mechanisms in the literature. Reviewing this comprehensively is beyond the scope of this entry. Only recent studies which specifically referred to abscesses are cited.
Among the risk factors identified in a review of bacterial infections in drug users were: injecting cocaine or heroin and cocaine mixtures (in both cases due perhaps to cocaine’s vasoconstrictive effects and in the former also to very frequent injection); skin popping as an injection technique (concentrating irritants and any bacteria in surface tissue rather than directly injecting in to the blood stream); not cleaning the skin at the injection site and other forms of poor hygiene such as licking needles; repeatedly drawing blood back in to the syringe before injecting (‘booting’ or ‘flushing’); injecting with unclean equipment; sharing potentially contaminated equipment; and contaminated or particularly irritating drug mixtures. Avoidance of these risks is recommended as a preventive strategy.
Recent studies include one of 151 injectors treated for an abscess requiring incision and drainage at San Francisco General Hospital. They were compared against injectors matched on age, gender and race who had not recently suffered an abscess or major bacterial infection. Among what distinguished the abscess sufferers was a higher proportion who had injected a heroin and cocaine mixture (‘speedballing’), used skin popping as injection technique, drawn blood back in to the syringe before injecting, or injected with unclean equipment. The only practice positively protective against abscess was cleaning the injection site with alcohol before injecting. To prevent infections the authors recommended risk-reduction education and provision of clean needles and alcohol swabs.
As previously featured on Findings, also in California, more liberal needle exchange distribution policies have been associated with users receiving adequate supplies which in turn was associated with less sharing of injecting equipment and fewer injectors re-using their own equipment,  potentially reducing risk of damage at the injecting site. In this study the ‘raw’ number (ie, unadjusted for differences in caseload) of abscesses did not differ much between different types of exchange policies, but the figures were expressed in terms of the proportion (about 40%) of visitors who had experienced any such injury in the past year, not their frequency or severity. 
In Ireland, over a three-month period repeat visitors to a harm reduction service for drug users incorporating a needle exchange reduced their sharing of equipment, and from 40% the proportion who always cleaned their injecting site rose to 56%. This report also notes a 62% reduction in the number of visitors reporting abscesses, but the relevant table appears to show that the number and proportion (16–17%) were practically unchanged.
In 2006 a survey of drug injectors attending specialist harm reduction and treatment services in the UK found that just over a third had experienced an abscess, sore or open wound (all possible symptoms of an injecting site infection) during the previous year. Such events were more common among people who had injected crack cocaine or had been homeless during the same period. The report published by the Health Protection Agency speculates that increased crack cocaine injecting might account for the accompanying rise in the number of bacterial infections at injection sites. 
Similarly, in 2006 just over a quarter of injectors sampled from needle exchanges and treatment services in England had in the past three months had wounds or abscesses dressed (or received advice on how to do this).
In two Scottish cities about a third of injectors using needle exchanges had non-infected abscesses on the day they were surveyed. About 13% had infected abscesses, though about a fifth had these or other skin or tissue infections of some kind. Due to inadequate supplies and inconvenient access to them, re-use of one’s own equipment was common. Apart from ensuring adequate supplies of injecting equipment, these findings and laboratory tests led the researcher to conclude that the best ways to reduce health risks were to encourage hand washing before injections, provide sterile acidifiers, filters and single-use vessels for heating the drug solution, with appropriate education in their use. 
Practice Implications
The messages from the research and from the featured study seem to be that the costly and distressing occurrence of abscesses and other injection-site bacterial infections can be reduced by adequate supplies of needles and syringes combined with other equipment which comes into contact with the injection site or drug solution before injection, plus well-informed and well-communicated advice on how to avoid complications. Reliance in the UK on pharmacy-based needle exchanges limits the degree to which all this can be provided, but there is potential for allying these with more specialist provision to ensure access in an area to adequate preventive services. That specialist provision itself sometimes needs upgrading in terms of both equipment supply and the availability of relevant assessments and advice. Details below.
Treating abscesses and their complications is expensive, often requiring operating theatre time and two or three days of inpatient hospitalisation. On the basis of their study the researchers responsible for the featured study concluded that needle exchange is an effective strategy for curtailing this suffering and the costs that go with it. In this case needle exchange was packaged with advice and health care, potentially important because from the risk factors identified above (see In Context) it is clear that detailed advice is required to maximally prevent bacterial infection and abscess.
The extent to which this can be provided is limited by the fact that in 2005 perhaps three-quarters of England’s needle exchanges were based in pharmacies which account for perhaps two-thirds of all visits to exchanges. Compared to exchanges in services dedicated to drug users, in pharmacies there is less likely to be the space, time, inclination or staff training required for this work. Perhaps recognising this, in England nearly half the local pharmacy schemes which responded to the survey did not require participating pharmacies to provide face-to-face harm reduction advice and in over half the drug action team areas this was not available from any pharmacy. However most areas did have at least one or two drug-specialist exchanges, raising the possibility that these can work with pharmacies to ensure that an adequate abscess/infection prevention service is available in the area to which exchange users can be referred. Even among drug service exchanges, a third which responded to the survey said they did not include injecting hygiene in the initial assessment of new visitors and 29% did not provide face-to-face harm reduction advice. Access to sterile injecting equipment from exchanges of whatever kind fell well short of the level needed to permit use of a fresh needle each time (on average one syringe every two days) and only a minority provided some other equipment such as sterile water. 
In Scotland at about the same time, syringe supplies from exchanges were even more limited – at best an average of one every three days. As in England, pharmacies provided three-quarters of exchanges services though most areas did host a non-pharmacy exchange. Partly because some of these were not in dedicated drug services (eg, in hospitals or police custody suites), just 28 out of 45 covered injecting hygiene in the initial assessment of new visitors, which itself was often not systematically undertaken. Face-to-face harm reduction advice was available in only half the pharmacy schemes, and, as in England, some types of equipment such as sterile water were rarely provided.