Theme: Epidemiology & Public Health Research Year: 2018
Estimates of the population size of people who inject drugs (PWID) are important to
assess harm reduction coverage and HCV burden. In Greece, extant estimates are
based on capture-recapture applied yearly to three drug treatment sources. We aim to
provide estimates for Athens based on data from a community-based program and to
assess implications concerning HCV burden and harm reduction coverage.
ARISTOTLE was a seek-test-treat intervention implemented during an HIV outbreak
in 2012-2013. During five Respondent-Driven Sampling (RDS) rounds, 3,320 unique
PWID were recruited; 81% had injected in the past month. Two methods were used:
1) Capture-recapture (CRC) based on five RDS rounds, 2) Multiplier method (MM)
based on the number of newly diagnosed HIV cases during 2009-2013 and the HIV
prevalence estimate from ARISTOTLE (HIV prevalence was negligible before 2009).
Based on CRC, the estimated number of PWID who reported heroin as main
substance of use in the past year was 4,731 in 2013 (95%CI: 4,175–5,287). The
number of persons with injecting drug use in the past month was 4,367 (95%CI: 3,893–
4,840]. Based on this estimate, the coverage of needle and syringe programs in Athens
in 2013 is 97 syringes/PWID/year (vs. 216 syringes/PWID/year based on the existing
population size estimate). As HCV prevalence in the target population is 80.4%, the
number of active PWID with HCV infection in Athens is estimated 3,500 (vs. 1,600
based on the existing population size estimate). Under the MM approach, the size of
PWID for the period 2009-2013 was 6,964 (95%CI: 6,455–7,559); the estimated total
number of HCV infected PWID for this period is 5,600.
The estimate of the population size of PWID in Athens based on a community-based
program indicates increased needs concerning the prevention of harm and the
reduction of HCV burden in the population.