The epidemiology of injection drug use and bloodborne infection in Ontario

Transcription

1 The epidemiology of injection drug use and bloodborne infection in Ontario Robert S. Remis, MD, MPH, FRCPC Ontario HIV Epidemiologic Monitoring Unit Department of HIV-IDU Frontline Workers Conference Toronto, February 24, 2005

2 Background HIV epidemic in Ontario is unstable and dynamic Critical to monitor trends in HIV transmission (incidence) and burden of HIV infection (prevalence) to evaluate effectiveness of prevention and assess the need for health and support services

3 Organization of presentation Methods and results Characterization of IDUs HIV incidence and prevalence - studies Modeled HIV incidence and prevalence HCV-HIV co-infection Limitations Conclusions

4 Methods Characterization of IDUs capture-recapture study method of Holmberg 1996 characteristics - epidemiologic studies HIV incidence and prevalence - review of seroepidemiologic studies

5 Methods Modeled HIV incidence and prevalence iterative spreadsheet model incorporating available results from epi studies, reported HIV diagnoses, detuned assay and repeat testers HCV-HIV co-infection Remis 2000 interpolated to Ontario

6 Estimated number of IDUs,, 2002 Region Population Number IDUs Northern 908,108 3,100 Ottawa 742,969 3,300 Eastern, other 781,206 2,100 Toronto 2,462,510 16,300 Central East, other 2,602,222 5,700 Central West 2,118,152 5,700 Southwest 1,485,709 5,000 Total 11,100,876 41,100

7 Characteristics of IDUs Majority (65-75%) of IDUs male thus, rate of injection 2-3 times higher in males Young age: most years old Rates of injection greatest in major urban centres though rural pockets also occur Drug of choice varies by centre: More cocaine in Ottawa and Northern Ontario, more heroin in Toronto Most (85%+) tested for HIV but not necessarily frequently

8 First-time HIV-positive diagnoses among males (n=21,325), Ontario, % 0.8% 3.5% 0.8% 4.2% 1.0% 1.3% 76.8% MSM MSM-IDU IDU Clotting factor Transfusion HIV-endemic HR hetero LR hetero Perinatal Other 4.6% 6.6%

9 First-time HIV-positive diagnoses among females (n=3,409), Ontario, % 20.0% 16.4% IDU Clotting factor Transfusion HIV-endemic HR hetero LR hetero Perinatal Other 5.3% 1.1% 17.6% 1.9% 4.8%

10 HIV diagnoses for selected exposure categories, * Number of cases HIV-endemic LR hetero HR hetero MSM-IDU IDU * Annual, projected from first half of year

11 HIV prevalence among IDUs in Ontario Toronto, Men %, Women %, Overall % Ottawa, Men 12-21%, Women %, Overall 12-21% Sudbury, 1998 & 2003 Men 5.6%, Women 30%, Overall 10-12%

12 Modeled HIV prevalence and diagnoses by exposure category, Ontario, 2003 HIV Proportion HIV Proportion prevalence Ontario diagnosed diagnosed MSM 14, % 9, % MSM-IDU % % IDU 1, % 1, % Endemic 3, % 1, % Hetero 3, % 1, % Clotting % % Transfusion % % 23, % 14, %

13 Modeled HIV prevalence among IDUs Ontario, Proportion HIV infected 6.0% 5.0% 4.0% 3.0% 2.0% 1.0% Prevalence % Prevalence number 2,500 2,000 1,500 1, Number of HIV-infected IDUs 0.0% Year 0

14 HIV incidence (per 100py) among IDUs in Ottawa Ottawa, SurvIDU ( ) Men 7.6, Women 2.9, Overall 5.8 Ottawa, POINT project, 2004 Men 2.9, Women 2.1, Overall 2.3

15 HIV incidence (per 100 p-y) among IDUs in Ontario Men Women Overall Northern Ottawa Eastern, other Toronto Central East, other Central West Southwest Ontario Source: Laboratory Enhancement Study

16 HIV incidence from detuned assay among IDU, Ontario, October 1999 December Incidence density (/100 p-y) ID measured ID adjusted Source: Laboratory Enhancement Study

17 HIV incidence from detuned assay among IDU, Toronto, October 1999 December Incidence density (/100 p-y) ID measured ID adjusted Source: Laboratory Enhancement Study

18 HIV incidence from detuned assay among IDU, Ottawa, October 1999 December Incidence density (/100 p-y) ID measured ID adjusted Source: Laboratory Enhancement Study

19 HIV incidence from detuned assay among IDU, other regions, October 1999 December Incidence density (/100 p-y) ID measured ID adjusted Source: Laboratory Enhancement Study

20 Modeled IDU number, HIV prevalence and incidence by health region, Ontario, 2003 Health region (aggregated) Prevalence IDU Number IDU Prevalence HIV Number HIV Annual HIV incidence (%) Annual HIV incidence (No.) Toronto 0.60% 15, % % 30 Ottawa 0.40% 3, % % 15 Rest of Ontario 0.20% 17, % % 35 Ontario, total 0.31% 36, % 1, % 80

21 HCV infection among IDUs in Ontario Toronto 54%, Ottawa 58-76%, Sudbury 62% 20,000-30,000 active IDUs are HCV-infected Estimated HIV-HCV coinfected 1,800 Essentially all HIV-infected IDUs also have HCV

22 Limitations Populations at risk not well characterized Adjustments for HIV diagnoses, AIDS cases and HIV-related mortality subject to uncertainty Data on HIV incidence limited and biased Despite challenges, triangulation allows obtaining plausible estimates for HIV incidence and prevalence

23 Conclusions In general, situation with respect to HIV among IDUs relatively reassuring in Ontario, especially Toronto Ottawa: explosive outbreak in and HIV prevalence and incidence higher than elsewhere Also, concern about Sudbury and Thunder Bay HIV prevalence 1,960 (8% of Ontario); 67% diagnosed; rate 5% (Ottawa 15%, elsewhere 4%); [ 7.6% since new HIV infections in 2003; incidence ~0.2%

24 Acknowledgements Frank McGee, AIDS Bureau, Ontario Ministry of Health and Long Term Care (MOHLTC) Carol Swantee,, HIV Laboratory, MOHLTC Jane Njiah,, FSO, PHAC / MOHLTC Maraki Fikre Merid,, University of Toronto Lorraine Schiedel,, Public Health Branch, MOHLTC Ontario HIV Treatment Network (OHTN) and Health Canada for funding Laboratory Enhancement Study