What works: prevention for drug injectors. Holly Hagan Don C. Des Jarlais. Corina Lelutiu-Weinberger

Transcription

1 What works: A synthesis of research on HCV prevention for drug injectors Holly Hagan Don C. Des Jarlais Enrique R. Pouget Corina Lelutiu-Weinberger Center for Drug Use and HIV Research NDRI New York, NY

2 Background What works for HIV prevention does not necessarily control HCV Host, agent and environmental factors favor endemic HCV in IDUs Risk reduction vs. risk elimination Large reservoir of infectious individuals Injection as a complicated process in a chaotic setting

3 Outline of this talk Summarize Meta-analysis of association between HCV seroconversion and prevention Meta-regression of interval from onset of injection to HCV infection Discuss Implications for research and prevention

4 Methods - HCV Synthesis Project Design and scope Meta analysis and synthesis of research on HCV epidemiology and prevention in drug users throughout the world Data collection Published and unpublished data sought Encompassed studies published since the discovery of HCV Sample January 1989 to December ,375 reports identified and screened 628 eligible reports

5 Meta-analysis of association between HCV seroconversion and prevention Included all HCV incidence studies reporting on the association with prevention measures: Drug treatment Needle exchange Used adjusted OR/RR/HR when available All observational epidemiology studies Evaluated heterogeneity & calculated summary estimates of the effect ect on HCV seroconversion Comprehensive Meta-Analysis software Examined operational definition of prevention Dose or type?

6 Drug Treatment 1 st Author Study Dates Location N Definition of Treatment Brunton 1996 New Zealand (multi-site) 39 Hagan Seattle 484 Lamothe 1992 Montreal 63 Maher Sydney 368 Patrick Vancouver 155 In treatment (not specified) at follow-up interview In treatment e t (not specified) ed) at baseline In treatment (not specified) at follow-up interview In treatment (not specified) at baseline Addiction therapy (not methadone) during follow-up Addiction treatment (not Smythe Dublin 98 specified) more than 3m vs. less during follow-up

7 Drug Treatment t Model First Author Statistics for each study Odds ratio and 95% CI Odds Lower Upper ratio limit limit Z-Value p-value Brunton Hagan ' Lamothe Maher Patrick Smythe Fixed Random Less Risk More Risk Significant Heterogeneity

8 Opioid Replacement Therapy 1 st Author Study Dates Location N Definition of Opioid Replacement Therapy Crofts Victoria 73 Dolan New South Wales prisons Continuous vs. none or interrupted MMT during follow-up o 222 Any vs. no MMT during follow-up Hall Sydney y 54 Continuous vs. interrupted ORT during follow-up Lucidarme France (multisite) 131 In substitutive treatment vs. not during 3m before baseline Patrick Vancouver 155 Methadone therapy last 6m of follow-up Rezza Naples 106 Any vs. no methadone treatment during last 6m of follow-up Thiede Seattle 78 Continuous vs. interrupted MMT during follow-up van Beek Sydney 144 Ever vs. never receive MMT van den Berg Amsterdam 903 Any methadone treatment during follow-up

9 Opioid id Replacement Therapy Model First Author Statistics for each study Odds ratio and 95% CI Odds Lower Upper ratio limit limit Z-Value p-value Crofts Dl Dolan Hall Lucidarme Patrick Rezza Thiede van Beek van den Berg Fixed Random Less Risk More Risk Non-significant Heterogeneity

10 Opioid id Replacement Therapy (Continuous Treatment) t) Model First Author Statistics for each study Odds ratio and 95% CI Odds Lower Upper ratio limit limit Z-Value p-value Crofts Hall Thiede Fixed Random Less Risk More Risk Non-significant Heterogeneity

11 NEP Participation 1 st Author Study Dates Location N Definition of NEP participation Hagan Tacoma 66 Ever vs. never Hagan Seattle 484 Lamothe 1992 Montreal 63 Patrick Vancouver 155 Roy Montreal 359 Thorpe Chicago 353 Ever vs. never during follow- up; also frequency, recency Any vs. none last 6m followup Frequent attendance vs. less last 6m of follow-up Any vs. none last 6m followup Any vs. none last 6m follow- up

12 NEP Participation i Model First Author Statistics for each study Odds ratio and 95% CI Odds Lower Upper ratio limit limit Z-Value p-value Hagan ' Hagan ' Lamothe Patrick Roy Thorpe Fixed Random Less Risk More risk Sgnificant Heterogeneity

13 Control of Confounding? Note Rezza et al 1996: The association between HCV seroconversion and MMT during follow-up OR = 2.8 (1.1, 7.4) AOR* = 0.34 (0.10, 1.11) *Controlled for age, duration injecting, i daily injecting, injecting cocaine, sharing of drug preparation p and injection equipment, sexual partnership characteristics

14 Meta-regression of interval from onset of injection to HCV infection No standardized categories of time since onset of injection For each study, calculated the midpoint of time- categories Each category represented by a single value Potential ti effect modifiers Data collection vs. later 1995 chosen a priori to represent a division between an early period and the expansion of harm reduction programs Developing/transitional country Linear mixed effects meta-regression models of HCV rates for time at risk categories

15 Results: HCV prevalence in relation to time at risk 72 studies reporting prevalence in relation to time since onset of injection time at risk 293 categories of time at risk 31% conducted f d l l 19% from developing or transitional countries

16 Observed and fitted HCV prevalence in relation to time at risk

17 Mean fitted values: HCV prevalence two years after onset of injection Prevalence 95% CI Developing/transitional countries 57.9% % Non-developing/transitional countries % % 5% Non-developing/transitional countries post % %

18 Summary Confounding in individual-level observational studies of the association between HCV infection and harm reduction Volunteer bias in needle exchange Hagan et al, 2001 Frequent needle exchange use and higher risk Wood et al, 2007 Community-level trends and analysis of time to infection strongly suggest that harm reduction is working BUT need more knowledge regarding dose-response relationship contribution of individual components

19 What works: Encouraging findings are nice, but Knowledge is limited Exactly what aspects of prevention are working is unclear What elements should be increased? What is unnecessary? How much [more] prevention is needed? What level of endemic HCV will we have to live with? Is it conceivable that prevalence will decline over the next ten years?

20 Acknowledgements The HCV Synthesis Project was funded by the National Institute on Drug Abuse RO1 DA 18609