Correlates of disparities in syringe return ratios: A cross-sectional study of a syringe services program in New York.

BACKGROUND: Predictors of syringe exchange behavior are critical to informing secondary prevention measures needed to attenuate risk of blood-borne infections among persons who inject drugs (PWID). METHODS: Participants included PWIDs who attended a syringe services program in New York from 2015 to 2017 (n = 1777). We analyzed the syringe return ratio (receipts/returns) with two distinct but related methodological strategies-threshold logistic regression and quantile regression-to identify correlates of disparities in syringe return ratios. RESULTS: The majority of participants were white males negative for HIV (90% white, 63% male, 76% HIV-). Logistic and quantile regression models showed that the correlates of disparate syringe return ratios (i.e., magnitude and directionality of differences) changed across different percentile groups and quantile levels, respectively. At the median threshold, being single, urbanicity, and older age were associated with higher return ratios. Syringe return ratio disparities were more pronounced among subgroups of nontypical PWIDs (with extremely low or high return ratios) especially by urbanicity, race, relationship status, and type of housing. CONCLUSIONS: Irrespective of urbanicity classification, correlates of syringe return ratios such as older age, Black race, single relationship status, and unstable housing appear to be critical to informing targeted secondary prevention initiatives that promote harm reduction behavior.

Prevalence and correlates of receptive syringe-sharing among people who inject drugs in rural Appalachia.

BACKGROUND AND AIMS: Syringe-sharing significantly increases the risk of HIV and viral hepatitis acquisition among people who inject drugs (PWID). Clearer understanding of the correlates of receptive syringe-sharing (RSS) is a critical step in preventing bloodborne infectious disease transmission among PWID in rural communities throughout the United States. This study aimed to measure the prevalence and correlates of RSS among PWID in a rural county in Appalachia. DESIGN: Observational, cross-sectional sample from a capture-recapture parent study. SETTING: Cabell County, West Virginia (WV), USA, June-July 2018. PARTICIPANTS: The sample was restricted to people who reported injecting drugs in the past 6 months (n = 420). A total of 180 participants (43%) reported recent (past 6 months) RSS. Participants reported high levels of homelessness (56.0%), food insecurity (64.8%) and unemployment (66.0%). MEASUREMENTS: The main outcome was recent re-use of syringes that participants knew someone else had used before them. Key explanatory variables of interest, selected from the risk environment framework, included: unemployment, arrest and receipt of sterile syringes from a syringe services program (SSP). Logistic regression was used to determine correlates of recent RSS. FINDINGS: PWID reporting recent RSS also reported higher prevalence of homelessness, food insecurity and unemployment than their non-RSS-engaging counterparts. In adjusted analyses, correlates of RSS included: engagement in transactional sex work [adjusted odds ratio (aOR) = 2.27, 95% confidence interval (CI) = 1.26-4.09], unemployment (aOR = 1.67, 95% CI = 1.03-1.72), number of drug types injected (aOR = 1.33, 95% CI = 1.15-1.53) and injection in a public location (aOR = 2.59, 95% CI = 1.64-4.08). Having accessed sterile syringes at an SSP was protective against RSS (aOR = 0.57, 95% CI = 0.35-0.92). CONCLUSION: The prevalence of receptive syringe-sharing among people who inject drugs in a rural US county appears to be high and comparable to urban-based populations. Receptive syringe-sharing among people who inject drugs in a rural setting appears to be associated with several structural and substance use factors, including unemployment and engaging in public injection drug use. Having recently acquired sterile syringes at a syringe services program appears to be protective against receptive syringe sharing.

Reuse of syringes for therapeutic injections in Pakistan: rethinking determinants.

BACKGROUND: Frequent reuse of syringes during medical injections is fuelling epidemics of human immunodeficiency virus and hepatitis C virus infections in many low- and middle-income countries including Pakistan. AIMS: To explore specific factors related to syringe reuse during therapeutic injections. METHODS: We randomly surveyed 319 healthcare providers from 2 socioeconomically diverse districts in Pakistan, along with 625 of their patients. RESULTS: Providers see 12-25 patients per day, and provide 7-14 therapeutic injections or intravenous drips. Comparing daily stocks with injections provided, we estimated that 38% of providers (Rawalpindi: 14%, Tando Allah Yar: 44%) likely reuse syringes 2 or 3 times. Rural location and longer duration of practice predict a higher likelihood of reuse. Physicians and non-physicians were equally likely to reuse. Most patients were unaware when a syringe had been reused. CONCLUSIONS: High rate of syringe reuse is driven by high injection demand by patients, to which providers comply. Patients are generally unaware of the harm of injections with syringe reuse or that reuse happens. Our findings suggest that patient focused approaches may help reduce syringe reuse.

Longitudinal Factors Associated with Used Syringe Lending Among HIV-Positive Antiretroviral Therapy-Naïve People Who Inject Drugs in a Canadian Setting.

Sharing used syringes is an important route of HIV transmission, however, factors shaping used syringe-lending among antiretroviral therapy (ART)-naïve HIV-positive people who inject drugs (PWID) are not well-characterized. Multivariable logistic regression analyses using generalized estimating equations (GEE) were employed to investigate correlates of used syringe lending among ART-naïve PWID. Data was drawn from ACCESS, a prospective community-recruited cohort of HIV-positive illicit drug users in Vancouver, Canada, from 1996 to 2015. The analysis included 482 ART-naïve PWID, of which 116 (24.1%) reported ≥ 1 periods of used syringe lending. In longitudinal analyses, incarceration (Adjusted Odds Ratio [AOR] = 2.18, 95% Confidence Interval [CI] 1.48-3.20), daily cocaine injection (AOR= 1.97, 95% CI 1.33-2.90), and sex work (AOR = 1.61, 95% CI 1.02-2.55) during the 180-day observation period were positively associated with used syringe lending, while having a high school diploma (AOR = 0.63, 95% CI 0.43-0.93) and holding formal employment (AOR = 0.20, 95% CI 0.05-0.82) were negatively associated. We found a high prevalence of used syringe lending among ART-naïve HIV-positive PWID, particularly among those recently incarcerated, involved in sex work or who injected cocaine frequently. Conversely, markers of higher socio-economic status were negatively associated with used syringe lending. These findings highlight the critical need for policies and interventions to decrease socio-economic marginalization and criminalization among PWID living with HIV alongside the scale up of access to harm reduction services.

Expansion of Syringe Service Programs in the United States, 2015-2018.

Objectives. To report on the expansion of syringe service programs (SSPs) in the United States from 2015 to 2018.Methods. We obtained data from records of the Buyers' Club of the Dave Purchase Project/North American Syringe Exchange Network (NASEN), including the number of US SSPs and the numbers of sterile syringes purchased by programs. We conducted a subset analysis of states with high numbers of counties defined as "vulnerable" by the Centers for Disease Control and Prevention.Results. SSP participation in the Buyers' Club increased from 141 in 2015 to 292 in 2018, with an increase in syringes purchased from 42 million to 88 million. In addition to these large increases in numbers of programs and in syringes purchased, there were also indications of instability among new programs in vulnerable states.Conclusions. There have been substantial increases in the number of programs established and the number of syringes distributed in response to the opioid epidemic. Ensuring high-quality services in these new programs will be critical to successfully addressing the current epidemic.

Syringe disposal among people who inject drugs before and after the implementation of a syringe services program.

INTRODUCTION: Due to the increase in people who use opioids in the US, there has been a steady increase in injection drug use. Without access to safe syringe disposal locations, people who inject drugs (PWID) have few options other than improper disposal, including in public places. In 2016, Florida's first legal Syringe Services Program (SSP) was established in Miami. This study aims to compare syringe disposal practices among PWID before and after the implementation of an SSP. METHODS: Visual inspection walkthroughs of randomly selected census blocks in the neighborhoods in the top quartile of narcotics-related arrests were conducted to assess improperly discarded syringes. Syringe location was geocoded in ArcGIS. Adult PWID pre-SSP (n = 448) and post-SSP (n = 482) implementation were recruited for a survey using respondent-driven sampling in Miami. A Poisson regression model was used to determine the adjusted relative risk (aRR) of improper syringe disposal pre- and post-SSP. RESULTS: A total of 191 syringes/1000 blocks were found post-implementation versus 371/1000 blocks pre-implementation, representing a 49% decrease after SSP implementation. In the surveys, 70% reported any improper syringe disposal post-SSP implementation versus 97% pre-SSP implementation. PWID in the post-implementation survey had 39% lower adjusted relative risk (aRR = 0.613; 95% CI = 0.546, 0.689) of improper syringe disposal as compared to pre-implementation. CONCLUSIONS: There was a significant decrease in the number of improperly discarded syringes in public in Miami after the implementation of an SSP. Providing PWID with proper disposal venues such as an SSP could decrease public disposal in other communities.

The Role of Gender in the Health and Human Rights Practices of Police: The SHIELD Study in Tijuana, Mexico.

Globally, punitive drug law enforcement drives human rights violations. Drug control tactics, such as syringe confiscation and drug-related arrests, also cascade into health harms among people who use drugs. The role of police officer characteristics in shaping such enforcement and measures to reform police practices remains underexamined. We evaluated gender differences in syringe confiscation and syringe-related arrest behaviors among municipal police officers in Tijuana, Mexico, where syringe possession is legal. In the context of the SHIELD Study focusing on aligning policing with harm reduction measures, our baseline sample covered municipal police officers who reported having occupational contact with syringes. We used multivariable logistic regression with robust variance estimation via a generalized estimating equation to identify correlates of syringe-related policing behaviors. Among respondent officers (n=1,555), 12% were female. After considering possible confounding variables, such as district of service and work experience, female officers were significantly less likely to report confiscating syringes or arresting individuals for syringe possession. Consideration of officer gender is important in the design of interventions to improve the health and human rights of people who inject drugs and other highly policed groups, as well as measures to safeguard officer occupational safety. The feminization of law enforcement deserves special consideration as an imperative in reducing the public health harms of policing.

A Cost Minimization Analysis of Ready-to-Administer Prefilled Sterilized Syringes in a Dutch Hospital.

PURPOSE: Preparation errors occur frequently during conventional preparation of parenteral medication in the clinical environment, causing patient harm and costs for the national health care system. The use of ready-to-administer prefilled sterilized syringes (PFSSs) produced by the hospital pharmacy can reduce preparation errors and the risk of bacteremia from contamination of the intravenous medication. The aim of this research is to compare the total costs of the conventional preparation method (CPM) with the PFSS method. METHODS: In this cost-minimization analysis, costs related to the preparation of the medication, bacteremia from contamination, adverse drug events as a result of preparation medication errors, and wastage of syringes were taken into account. Annual costs in a general Dutch hospital were consistently calculated. Three scenarios were analyzed: (1) all preparations as CPM (864,246 administrations per year), (2) all preparations as PFSSs, and (3) 50% as PFSSs and 50% as CPM. Deterministic and probabilistic sensitivity analyses were performed. FINDINGS: The first scenario found higher annual costs at €14.0 million (US$16.0 million) compared with the second scenario (€4.1 million, US$4.7 million). The most realistic situation (third scenario) found savings of €4.9 million (US$5.6 million) compared with the first scenario. Sensitivity analyses revealed that cost savings of PFSSs were strongly influenced by decreased risk of medication errors and contamination of intravenous medication. Extrapolating these results nationwide indicated potential savings of >€300 million (US$342 million) if only PFSSs were used. IMPLICATIONS: The use of PFSSs prepared in the hospital pharmacy yielded cost savings compared with the CPM on the ward in the Dutch hospital.

Uptake into a bedside needle and syringe program for acute care inpatients who inject drugs.

INTRODUCTION AND AIMS: Injection drug use is associated with significant morbidity and mortality worldwide. Needle and syringe programs (NSP) have been shown to reduce negative health outcomes for people who inject drugs. However, NSPs have limited reach in hospitals, and no peer-reviewed research has examined NSP implementation in acute care settings. We describe the implementation of an inpatient NSP offered through an addiction medicine consultation service in a large, urban acute care hospital in Edmonton, Canada, and compared characteristics of inpatients who did versus did not access the NSP. DESIGN AND METHODS: Administrative data were reviewed for all addiction medicine consult service intakes between 11 July 2016 and 14 January 2018. We calculated the proportion of intakes in which patients: (i) were offered syringes; and (ii) accepted syringes. Multivariate analyses were used to examine associations between these outcomes and patient age and sex. RESULTS: Patients reported injecting drugs in 597 (31%) of 1907 intakes during the study period. People who inject drugs were offered syringes in 334 (56%) of these intakes, and accepted syringes in 124 (37%) of them. Female patients were more likely to accept syringes. DISCUSSION AND CONCLUSIONS: In a recently implemented NSP for hospital inpatients, just over half of patients who reported injection drug use were offered syringes, and the rate of patient acceptance was low. Further research is necessary to describe best practice for inpatient NSPs and identify and remove any barriers that prevent some inpatients from either being offered or accepting syringes.

Estimating the number of people who inject drugs and syringe coverage in Australia, 2005-2016.

BACKGROUND: Effective targeting of harm reduction programs for people who inject drugs (PWID) requires timely and robust estimates of the size of this population. This study estimated the number of people who inject drugs on a regular basis in Australia, calculated syringe coverage per person and the proportion of their injections covered by a sterile needle and syringe. METHODS: We used trends in indicators of injection drug use to extend the 2005 estimate of the population of people who regularly inject drugs from 2005 to 2016. Included indicators were lifetime/recent injection of illicit drugs, drug-related arrests, drug-related seizures, accidental deaths due to opioids, opioid-related hospital admissions/separations and new diagnoses of hepatitis C virus infection among those aged 15-24 years. Syringe distribution and frequency of injection data were used to assess syringe coverage per PWID and the proportion of their injections covered by a sterile syringe. RESULTS: The estimated number of people who regularly inject drugs in Australia increased by 7%, from 72,000 in 2005 to 77,270 in 2016. The annual number of syringes distributed per person increased 34%, from 470 syringes in 2005 to 640 syringes in 2016. Syringe coverage per injection first exceeded 100% in Australia in 2013. CONCLUSIONS: Despite Australia's high syringe coverage by international standards, the number of syringes distributed is likely to be only narrowly meeting demand. It is critical that needle syringe programs be provided with sufficient resources to continue their role as the key intervention required to prevent HIV and HCV transmission among PWID.

Three-dimensional Printing of Thermoplastic Materials to Create Automated Syringe Pumps with Feedback Control for Microfluidic Applications.

Microfluidics has become a critical tool in research across the biological, chemical, and physical sciences. One important component of microfluidic experimentation is a stable fluid handling system capable of accurately providing an inlet flow rate or inlet pressure. Here, we have developed a syringe pump system capable of controlling and regulating the inlet fluid pressure delivered to a microfluidic device. This system was designed using low-cost materials and additive manufacturing principles, leveraging three-dimensional (3D) printing of thermoplastic materials and off-the-shelf components whenever possible. This system is composed of three main components: a syringe pump, a pressure transducer, and a programmable microcontroller. Within this paper, we detail a set of protocols for fabricating, assembling, and programming this syringe pump system. Furthermore, we have included representative results that demonstrate high-fidelity, feedback control of inlet pressure using this system. We expect this protocol will allow researchers to fabricate low-cost syringe pump systems, lowering the entry barrier for the use of microfluidics in biomedical, chemical, and materials research.

Analysis of time of drug use according to needle and syringe program operating hours in Melbourne, Australia: Effects on individual-level needle and syringe coverage.

BACKGROUND: Restricted needle and syringe program (NSP) operating hours in Australia have been reported as a barrier to access for people who inject drugs (PWID). We explored the prevalence of drug use occurring outside NSP operating hours with a particular focus on its impacts on individual-level needle and syringe coverage. METHODS: Using data from 584 participants in a cohort of PWID in Melbourne, Australia, we analyzed time and day of drug use for heroin, methamphetamine and pharmaceutical opioids. We related this drug use to the typical operating times of Melbourne's fixed-site NSPs, categorizing drug use as either "in-hours" or "out-of-hours". We explored associations with out-of-hours drug use using a generalized linear mixed model of pooled longitudinal data. RESULTS: 23% of heroin use and 50% of methamphetamine use occurred out-of-hours. In regression analysis, males and those injecting in public locations had significantly reduced odds of out-of-hours drug use. Those currently employed and those using methamphetamine (compared to heroin) had significantly increased odds of out-of-hours drug use. There was no significant association between individual-level needle and syringe coverage and hours of drug use. CONCLUSIONS: Deficiencies in individual-level needle and syringe coverage may not be due to restricted NSP operating hours. Instead, insufficient coverage may be the result of other factors in the lives of PWID or other NSP access difficulties. These preliminary results suggest improvements to coverage in Australia may not result from increased hours of NSP operation, but instead via improvements to client targeting.

Measuring individual-level needle and syringe coverage among people who inject drugs in Myanmar.

BACKGROUND: Myanmar has prioritised people who inject drugs (PWID) as a key population for HIV mitigation efforts, with targets for needle and syringe distribution set at a population level. However, individual-level coverage, defined as the percentage of an individual's injecting episodes covered by a sterile syringe, is a more sensitive measure of intervention coverage. We sought to examine individual-level coverage in a sample of PWID in Myanmar. METHODS: We recruited 512 PWID through urban drop-in-centres in Yangon, Mandalay and Pyin Oo Lwin. Participants were administered a quantitative questionnaire covering five domains: demographics, drug use, treatment and coverage, and injecting risk behaviour. We calculated past fortnight individual-level syringe coverage, estimating levels of sufficient (≥100% of injecting episodes covered by a sterile syringe) and insufficient (<100%) coverage, and examined associations between key variables and insufficient coverage via logistic regression. RESULTS: Our sample was predominately male (97%), employed (76%), and living in stable accommodation (96%), with a median age of 27. All participants reported heroin as the drug most frequently injected, and injected a median of 27 times in the past two weeks. Nineteen per cent of participants had insufficient coverage in the two weeks before interview. Insufficient coverage was positively associated with syringe re-use (AOR: 5.19, 95% CIs: 2.57, 10.48) and acquiring sterile syringes from a location other than a formal drop-in-centre (AOR: 2.04, 95% CIs: 1.08, 3.82). Participants recruited in Mandalay (AOR: 0.30, 95% CIs: 0.11, 0.80) and Pyin Oo Lwin (AOR: 0.39, 95% CIs: 0.18, 0.87) had lower odds of insufficient coverage than those recruited in Yangon. CONCLUSION: Our study shows coverage in selected areas of Myanmar was comparable with studies in other countries. Our results inform the delivery of harm reduction services for PWID, specifically by encouraging the use of formal drop-in-centres, over other sources of syringe distribution, such as pharmacies.

Syringe Port: A Convenient, Safe, and Cost-Effective Tubular Retractor for Transportal Removal of Deep-Seated Lesions of the Brain.

OBJECTIVE: Minimally invasive transportal resection of deep intracranial lesions has become a widely accepted surgical technique. Many disposable, mountable port systems are available in the market for this purpose, like the ViewSite Brain Access System. The objective of this study was to find a cost-effective substitute for these systems. METHODS: Deep-seated brain lesions were treated with a port system made from disposable syringes. The syringe port could be inserted through minicraniotomies placed and planned with navigation. All deep-seated lesions like ventricular tumours, colloid cysts, deep-seated gliomas, and basal ganglia hemorrhages were treated with this syringe port system and evaluated for safety, operative site hematomas, and blood loss. RESULTS: 62 patients were operated on during the study period from January 2015 to July 2017, using this innovative syringe port system for deep-seated lesions of the brain. No operative site hematoma or contusions were seen along the port entry site and tract. CONCLUSIONS: Syringe port is a cost-effective and safe alternative to the costly disposable brain port systems, especially for neurosurgical setups in developing countries for minimally invasive transportal resection of deep brain lesions.

Options for reducing HIV transmission related to the dead space in needles and syringes.

BACKGROUND: When shared by people who inject drugs, needles and syringes with different dead space may affect the probability of HIV and hepatitis C virus (HCV) transmission differently. METHODS: We measured dead space in 56 needle and syringe combinations obtained from needle and syringe programs across 17 countries in Europe and Asia. We also calculated the amounts of blood and HIV that would remain in different combinations following injection and rinsing. RESULTS: Syringe barrel capacities ranged from 0.5 to 20 mL. Needles ranged in length from 8 to 38 mm. The average dead space was 3 µL in low dead space syringes with permanently attached needles, 13 µL in high dead space syringes with low dead space needles, 45 µL in low dead space syringes with high dead space needles, and 99 µL in high dead space syringes with high dead space needles. Among low dead space designs, calculated volumes of blood and HIV viral burden were lowest for low dead space syringes with permanently attached needles and highest for low dead space syringes with high dead space needles. CONCLUSION: The dead space in different low dead space needle and syringe combinations varied substantially. To reduce HIV transmission related to syringe sharing, needle and syringe programs need to combine this knowledge with the needs of their clients.

Assessing individual-level needle and syringe coverage parameters and the measurement of coverage in Melbourne, Australia: methods and impacts.

Background: To assess the structure of individual-level needle and syringe coverage measurement formula, and to estimate the impact of coverage-related behaviours/parameters (instances of syringe acquisition, total syringes acquired, peer-to-peer syringe distribution, injecting frequency) on overall coverage. Methods: Data are drawn from the Melbourne (Australia) injecting drug user cohort study, 2010-16. Data from 518 participants were analysed. We used correlations to explore the relationships between coverage parameters; pooled multiple-linear regression to estimate the effect of each parameter on coverage over time; and exploratory factor analysis to assess the relevance of each parameter within the coverage formula. Results: A 1-unit increase in injecting frequency over time reduced coverage by 10.93 percentage points, almost twice as much as other coverage parameters. Factor analysis results indicated potential improvements to coverage formula structure. Conclusions: Our results suggest that reducing injecting frequency amongst people who inject drugs has the largest improvement in coverage levels, indicating harm reduction services should prioritize it. We also demonstrate that coverage measurement has been inconsistent to date. We sought to refine the method to assist in generating comparable research.

Dump the pump: manual aspiration thrombectomy (MAT) with a syringe is technically effective, expeditious, and cost-efficient.

INTRODUCTION: Syringe aspiration for manual aspiration thrombectomy (MAT) is a cost- and time-efficient alternative to an aspiration pump with likely similar efficacy. It is counterintuitive to expect the pump to perform better than direct vacuum with a syringe, as the pump must deliver vacuum additionally through a canister and meters of tubing. OBJECTIVE: To present in vitro and clinical results of MAT with a syringe. METHODS: An in vitro analysis was performed comparing vacuum pressures generated by syringe aspiration and with pump aspiration. This was then complemented with prospective clinical data providing details of angiographic and clinical outcomes for syringe MAT. RESULTS: The in vitro analysis demonstrated that equal to slightly greater vacuum pressures were generated by a 60 cc syringe as compared with the pump in both static and partial flow conditions. In our clinical series, 106/113 acute stroke thrombectomies over a 6-month period were performed with syringe MAT on the first pass. Syringe usage instead of pump tubing and a canister led to a total savings of $58 300. The rate of Thrombolysis in Cerebral Infarction 2b/3 recanalization was 93%. Adjunctive stentriever usage was performed in 23% of cases. Median puncture to reperfusion time was 25 min; mean change in National Institute of Health Stroke Scale score at 24 hours was an improvement of 5.1 (median 6). The in-hospital mortality rate was 10%. Seventy percent of patients were discharged to home (modified Rankin Scale (mRS) score 0-2) or a rehabilitation facility (mRS score 2-4). CONCLUSION: MAT using a syringe is a safe, fast, and more cost-effective approach than using an aspiration pump.

Needle acquisition patterns, network risk and social capital among rural PWID in Puerto Rico.

BACKGROUND: People who inject drugs (PWID) take on significant risks of contracting blood-borne infection, including injecting with a large number of partners and acquiring needles from unsafe sources. When combined, risk of infection can be magnified. METHODS: Using a sample of PWID in rural Puerto Rico, we model the relationship between a subject's number of injection partners and the likelihood of having used an unsafe source of injection syringes. Data collection with 315 current injectors identified six sources of needles. RESULTS: Of the six possible sources, only acquisition from a seller (paid or free), or using syringes found on the street, was significantly related to number of partners. CONCLUSIONS: These results suggest that sources of syringes do serve to multiply risk of infection caused by multi-partner injection concurrency. They also suggest that prior research on distinct forms of social capital among PWID may need to be rethought.

The impact of harm reduction programs and police interventions on the number of syringes collected from public spaces. A time series analysis in Barcelona, 2004-2014.

BACKGROUND: To estimate the effect of opening two services for people who use drugs and three police interventions on the number of discarded syringes collected from public spaces in Barcelona between 2004 and 2014. METHODS: We conducted an interrupted time-series analysis of the monthly number of syringes collected from public spaces during this period. The dependent variable was the number of syringes collected per month. The main independent variables were month and five dummy variables (the opening of two facilities with safe consumption rooms, and three police interventions). To examine which interventions affected the number of syringes collected, we performed an interrupted time-series analysis using a quasi-Poisson regression model, obtaining relative risks (RR) and 95% confidence intervals (CIs). RESULTS: The number of syringes collected per month in Barcelona decreased from 13,800 in 2004 to 1655 in 2014 after several interventions. For example, following the closure of an open drug scene in District A of the city, we observed a decreasing trend in the number of syringes collected [RR=0.88 (95% CI: 0.82-0.95)], but an increasing trend in the remaining districts [RR=1.11 (95% CI: 1.05-1.17) and 1.08 (95% CI: 0.99-1.18) for districts B and C, respectively]. Following the opening of a harm reduction facility in District C, we observed an initial increase in the number collected in this district [RR=2.72 (95% CI: 1.57-4.71)] and stabilization of the trend thereafter [RR=0.97 (95% CI: 0.91-1.03)]. CONCLUSION: The overall number of discarded syringes collected from public spaces has decreased consistently in parallel with a combination of police interventions and the opening of harm reduction facilities.