The impact of citrate introduction at UK syringe exchange programmes: a retrospective cohort study in Cheshire and Merseyside, UK.

Background: In 2003, it became legal in the UK for syringe exchange programmes (SEPs) to provide citrate to injecting drug users to solubilise heroin. Little work has been undertaken on the effect of policy change on SEP function. Here, we examine whether the introduction of citrate in Cheshire and Merseyside SEPs has altered the number of heroin/crack injectors accessing SEPs, the frequency at which heroin/crack injectors visited SEPs and the number of syringes dispensed.

Methods: Eleven SEPs in Cheshire and Merseyside commenced citrate provision in 2003. SEP-specific data for the six months before and six months after citrate was introduced were extracted from routine monitoring systems relating to heroin and crack injectors. Analyses compared all individuals attending pre and post citrate and matched analyses only those individuals attending in both periods (defined as 'longitudinal attenders'). Non-parametric tests were used throughout.

Results: Neither new (first seen in either six months period) nor established clients visited SEPs more frequently post citrate. New clients collected significantly less syringes per visit post citrate, than pre citrate (14.5,10.0; z = 1.992, P < 0.05). Matched pair analysis showed that the median number of visits for 'longitudinal attenders' (i.e. those who attended in both pre and post citrate periods) increased from four pre citrate to five post citrate (z = 2.187, P < 0.05) but the number of syringes collected remained unchanged. These changes were not due to seasonal variation or other changes in service configuration.

Conclusion: The introduction of citrate did not negatively affect SEP attendance. 'Longitudinal attenders' visited SEPs more frequently post citrate, providing staff with greater opportunity for intervention and referral. As the number of syringes they collected each visit remained unchanged the total number of clean syringes made available to this group of injectors increased very slightly between the pre and post citrate periods. However, new clients collected significantly less syringes post citrate than pre citrate, possibly due to staff concerns regarding the amount of citrate (and thus syringes) to dispense safely to new clients. These concerns should not be allowed to negatively impact on the number of syringes dispensed.