title: How far will they go? Assessing the travel distance of current and former drug users to access harm reduction services.
abstract: BACKGROUND
  Prior research has explored spatial access to syringe exchange programs (SEPs) among people who inject drugs (PWID), but little is known about service utilization by former PWID who continue to access services (e.g., HIV screenings and referrals for social services) at harm reduction providers. The purpose of this research is to examine differences in access to SEPs between current and former PWID seeking services at a mobile SEP in Washington, DC.
  
  
  RESULTS
  A geometric point distance estimation technique was applied to data collected as part of a PWID population estimation study that took place in Washington, DC, in March and April 2014. We calculated the walking distance from the centroid point of home residence zip code to the mobile exchange site where PWID presented for services. An independent samples t-test was used to examine differences in walking distance measures between current and former PWID. Differences in mean walking distance were statistically significant with current and former PWID having mean walking distances of 2.75 and 1.80 miles, respectively.
  
  
  CONCLUSIONS
  The results of this study suggest that former PWID who are engaging with SEPs primarily for non-needle exchange services (e.g., medical or social services) may have decreased access to SEPs than their counterparts who are active injectors. This research provides support for expanding SEP operations such that both active and former PWID have increased access to harm reduction providers and associated health and social services. Increasing service accessibility may help resolve unmet needs among current and former PWID.
authors.affiliation: Department of Prevention & Community Health, Milken Institute School of Public Health at The George Washington University, 950 New Hampshire Ave, Suite 300, Washington, DC, 20052, USA. seanallen@gwu.edu.
authors.forename: Sean
authors.initials: S
authors.lastname: Allen
authors.affiliation: Department of Prevention & Community Health, Milken Institute School of Public Health at The George Washington University, 950 New Hampshire Ave, Suite 300, Washington, DC, 20052, USA. msruiz@gwu.edu.
authors.forename: Monica
authors.initials: M
authors.lastname: Ruiz
authors.affiliation: Department of Prevention & Community Health, Milken Institute School of Public Health at The George Washington University, 950 New Hampshire Ave, Suite 300, Washington, DC, 20052, USA. orourkea@gwu.edu.
authors.forename: Allison
authors.initials: A
authors.lastname: O'Rourke
mesh_terms: D001294:Attitude to Health; D004219:District of Columbia / Q000453:epidemiology; D055030:Drug Users / Q000523:psychology* / Q000706:statistics & numerical data; D005260:Female; D015658:HIV Infections / Q000517:prevention & control*; D040261:Harm Reduction; D015438:Health Behavior; D006297:Health Services Accessibility; D006301:Health Services Needs and Demand; D006801:Humans; D008297:Male; D008875:Middle Aged; D018671:Needle-Exchange Programs / Q000706:statistics & numerical data*; D015819:Substance Abuse, Intravenous / Q000523:psychology* / Q000534:rehabilitation; D014195:Travel / Q000523:psychology* / Q000706:statistics & numerical data; D016138:Walking