title: Diverse HIV epidemics among people who inject drugs in Thailand: evidence from respondent-driven sampling surveys in Bangkok and Chiang Mai.
abstract: BACKGROUND
  Thailand's long-standing HIV sero-sentinel surveillance system for people who inject drugs (PWID) is confined to those in methadone-based drug treatment clinics and representative data are scarce, especially outside of Bangkok.
  
  
  METHODS
  We conducted probability-based respondent-driven sampling (RDS) surveys in Bangkok (n=738) and Chiang Mai (n=309) to increase understanding of local HIV epidemics and to better inform the planning of evidence-based interventions.
  
  
  RESULTS
  PWID had different epidemiological profiles in these two cities. Overall HIV prevalence was higher in Bangkok (23.6% vs. 10.9%, p<0.001) but PWID in Bangkok are older and appear to have long-standing HIV infections. In Chiang Mai, HIV infections appear to be more recently acquired and PWID were younger and had higher levels of recent injecting and sexual risk behaviors with lower levels of intervention exposure. Methamphetamine was the predominant drug injected in both sites and polydrug use was common although levels and patterns of the specific drugs injected varied significantly between the sites. In multivariate analysis, recent midazolam injection was significantly associated with HIV infection in Chiang Mai (adjusted odds ratio=8.1; 95% confidence interval: 1.2-54.5) whereas in Bangkok HIV status was not associated with recent risk behaviors as infections had likely been acquired in the past.
  
  
  CONCLUSIONS
  PWID epidemics in Thailand are heterogeneous and driven by local factors. There is a need to customize intervention strategies for PWID in different settings and to integrate population-based survey methods such as RDS into routine surveillance to monitor the national response.
authors: Thailand MOPH - U.S. CDC Collaboration, Nonthaburi 11000, Thailand; Division of Global HIV/AIDS, Centers for Disease Control and Prevention, Atlanta, 30333, USA. Electronic address: hjt1@cdc.gov.
authors: Dimitri
authors: D
authors: Prybylski
authors: Thailand MOPH - U.S. CDC Collaboration, Nonthaburi 11000, Thailand.
authors: Chomnad
authors: C
authors: Manopaiboon
authors: Thailand MOPH - U.S. CDC Collaboration, Nonthaburi 11000, Thailand.
authors: Prin
authors: P
authors: Visavakum
authors: Bangkok Metropolitan Administration, Bangkok 10200, Thailand.
authors: Kovit
authors: K
authors: Yongvanitjit
authors: Research Institute for Health Sciences, Chiang Mai, Thailand.
authors: Apinun
authors: A
authors: Aramrattana
authors: Bangkok Metropolitan Administration, Bangkok 10200, Thailand.
authors: Parnrudee
authors: P
authors: Manomaipiboon
authors: Thailand MOPH - U.S. CDC Collaboration, Nonthaburi 11000, Thailand.
authors: Suvimon
authors: S
authors: Tanpradech
authors: Thailand MOPH - U.S. CDC Collaboration, Nonthaburi 11000, Thailand.
authors: Orapin
authors: O
authors: Suksripanich
authors: Thailand MOPH - U.S. CDC Collaboration, Nonthaburi 11000, Thailand.
authors: Sarika
authors: S
authors: Pattanasin
authors: Thailand MOPH - U.S. CDC Collaboration, Nonthaburi 11000, Thailand; Division of Global HIV/AIDS, Centers for Disease Control and Prevention, Atlanta, 30333, USA.
authors: Mitchell
authors: M
authors: Wolfe
authors: Thailand MOPH - U.S. CDC Collaboration, Nonthaburi 11000, Thailand; Division of Global HIV/AIDS, Centers for Disease Control and Prevention, Atlanta, 30333, USA.
authors: Sara J
authors: SJ
authors: Whitehead
mesh_terms: D000293:Adolescent; D000328:Adult; D003430:Cross-Sectional Studies / Q000379:methods; D058872:Epidemics; D005260:Female; D015658:HIV Infections / Q000175:diagnosis* / Q000453:epidemiology* / Q000523:psychology; D006801:Humans; D008297:Male; D012309:Risk-Taking; D012725:Sexual Behavior / Q000523:psychology; D015819:Substance Abuse, Intravenous / Q000175:diagnosis* / Q000453:epidemiology* / Q000523:psychology; D013785:Thailand / Q000453:epidemiology; D055815:Young Adult
keywords: HIV; People who inject drugs; Respondent-driven sampling; Risk behaviors; Thailand
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