Few recent publications have highlighted theoretical and methodological challenges using respondent-driven sampling (RDS). To explore why recruitment with RDS may work in some populations and not in others, we assess the implementation of RDS to recruit female sex workers (FSWs) and injection drug users (IDUs) into a human immunodeficiency virus biological and risk behavior survey in Tallinn, Estonia. Recruitment of FSWs was slower and more challenging than that of IDUs. The IDU study recruited 350 participants within 7 weeks, while the FSW study recruited 227 participants over 28 weeks. Implementation modifications that did not negatively impact key RDS theoretical and methodological requirements were used to improve recruitment during the FSW study. We recommend that all RDS studies include a formative research process to involve the participation of target populations and key persons associated with these populations in the study planning and throughout the implementation processes to improve recruitment from the outset and to respond to poor recruitment during data collection.

Demographic and drug-use related factors are associated with having initiated someone into injecting. Interventions targeting PWID and non-PWID are needed to prevent injection initiation.

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BackgroundThis study seeks to identify the prevalence of, and risk factors associated with, non-fatal overdose among people currently injecting drugs (PWID) in St. Petersburg (Russia) and in Kohtla-Järve (Estonia).MethodsFive hundred eighty-eight study participants in Kohtla-Järve (in 2012) and 811 in St. Petersburg (in 2012–2013) were recruited using respondent driven sampling for interviewing and HIV testing.ResultsThree-quarters (76 %) of the current PWID were male. Participants from St. Petersburg were older (mean age 32.1 vs. 29.6 years, p < 0.0001) and reported a longer average duration of injecting drugs (mean duration: 13.3 vs. 10.9 years, p < 0.0001). Main drugs injected were opioids (fentanyl in Kohtla-Järve, heroin in St Petersburg). HIV prevalence was 63 % (95 % CI 59–67 %) in Kohtla-Järve and 56 % (95 % CI 52–59 %) in St. Petersburg. Two thirds of the PWID in Kohtla-Järve and St. Petersburg reported ever having experienced a drug overdose involving loss of consciousness or stopping breathing. In Kohtla-Järve, 28 % (95 % CI 24–31 %) of participants and, in St Petersburg, 16 % (95 % CI 14–19 %) of participants reported an overdose within the previous 12 months. Characteristics of injection drug use practice (longer duration of injection drug use, main drug injected), correlates of high-risk injection behaviour (higher injecting frequency, sharing), and problem alcohol use were associated with the risk of overdose within the previous 12 months. The significant factors effects did not differ between the sites.ConclusionsPWID are at high risk for overdose. Effective overdose prevention efforts at the public health scale are therefore warranted.

To assess the efficacy of an education- and strengths-based counselling programme to promote antiretroviral therapy (ART) adherence in a cohort of HIV-infected individuals with high prevalence of injection drug use in Estonia. Parallel-group randomized (1:1) controlled trial (RCT). Adults receiving ART in two clinics were followed for 12 months. The trial compared: (i) an intervention (three sessions) incorporated into routine clinic visits, providing education about HIV, ART, the role of adherence, and tailoring regimen to daily routines using problem-solving skills to address adherence barriers versus (ii) usual care (control). Primary and secondary outcomes were self-reported ART adherence (3-day recall) and viral load (respectively). 519 patients were randomized and 82% completed the study. Recent optimal ART adherence (3-day recall ≥95%) was reported by 75.6% in the intervention group and 72.9% of controls at baseline and 76.7% and 67.5%, respectively, at 12 months (RR 1.14, 95% CI 1.00-1.28; adjusted RR 1.13, 95% CI 1.00-1.27). There was no difference in the proportion of patients with undetectable viral load. At 12 months the intervention group reported significantly higher perceptions of ART necessity versus ART concerns [mean ART necessity-concerns differential: intervention group 1.32 (SD 1.22) vs control group 1.08 (SD 1.12); p = 0.048]. All-cause mortality among study participants was 27.7 per 1000 person years (95% CI 15.6-44.8). A brief, clinic-based adherence intervention alone may assist with adherence but lacks impact on viral load at 12 months.