Epidemiology of Hepatitis C Infection in Canada Robert S. Remis MD, MPH, FRCPC Department of Public...

Epidemiology of Epidemiology of Hepatitis C Infection Hepatitis C Infection in Canadain CanadaRobert S. Remis MD, MPH, Robert S. Remis MD, MPH, FRCPCFRCPC

Department of Public Health SciencesDepartment of Public Health SciencesUniversity of TorontoUniversity of Toronto

1st Canadian Conference on Hepatitis 1st Canadian Conference on Hepatitis CCMontreal, QuebecMontreal, Quebec

May 1-4, 2001May 1-4, 2001

instructional media centre, Laboratories Branch – 2001

AcknowledgementsAcknowledgements

Hepatitis C Transfusion Working Group, June 1998Hepatitis C Transfusion Working Group, June 1998 Robert S. Hogg, Murray D. Krahn, Robert W.H. Palmer, Jutta Robert S. Hogg, Murray D. Krahn, Robert W.H. Palmer, Jutta

K. Preiksaitis, Morris Sherman K. Preiksaitis, Morris Sherman

in collaboration within collaboration with JoAnne Chiavetta, PhD, Martin Tepper MD, JoAnne Chiavetta, PhD, Martin Tepper MD,

Shimian Zou MD and Bob Slinger MDShimian Zou MD and Bob Slinger MD

HCV-HIV Study, February 2000-March 2001HCV-HIV Study, February 2000-March 2001 Marcel DuBois, Chris Archibald, Jennifer GeduldMarcel DuBois, Chris Archibald, Jennifer Geduld Morris Sherman, Kevin Craib, Shimian ZouMorris Sherman, Kevin Craib, Shimian Zou

OthersOthers Michel Alary, Kevin Craib, Elaine WhittinghamMichel Alary, Kevin Craib, Elaine Whittingham


BackgroundBackground

Importance of hepatitis C was underestimated Importance of hepatitis C was underestimated due to delay in recognizing infectiondue to delay in recognizing infection

difficulties in developing diagnostic toolsdifficulties in developing diagnostic toolslong latency from infection to diseaselong latency from infection to disease

Need to better evaluate extent and Need to better evaluate extent and distribution distribution of HCV infection in Canadaof HCV infection in Canadadevelop appropriate guidelines for primary preventiondevelop appropriate guidelines for primary preventiondevelop guidelines for HCV testingdevelop guidelines for HCV testingassess burden of infection and disease in shortassess burden of infection and disease in short

and long term and long term plan appropriate health services and support programsplan appropriate health services and support programs


Overview of presentationOverview of presentation

1. Review of literature (published & 1. Review of literature (published & unpublished)unpublished)

2. Hepatitis C transmitted by blood 2. Hepatitis C transmitted by blood transfusiontransfusion

3. Hepatitis C prevalence and incidence in 3. Hepatitis C prevalence and incidence in CanadaCanada

4. Estimating number of persons in 4. Estimating number of persons in Canada with dual HCV-HIV infection Canada with dual HCV-HIV infection

5. Conclusions5. Conclusions


Selected seroepidemiologic Selected seroepidemiologic studies among IDUsstudies among IDUs

Author

Population

Location

Study year

Sample size

HCV prevalence

Strathdee IDUs Vancouver 1996-97 1,006 88%

Lamothe IDUs Montreal 1992-96 282 70% Incidence 27%

LCDC IDUs CBI Nova Scotia

1996-97 92 47%

Romanowski IDUs STD clinic

Alberta 1994-95 6,668 41% Men 46%

Women 31%


Selected seroepidemiologic Selected seroepidemiologic studies among prisonersstudies among prisoners

Author Population LocationStudyyear

Samplesize

HCVprevalence

Prefontaine Males BritishColumbia

1990 415 26%

Ford Females Kingston,Ontario

1994 133 40%

Ford Males Kingston,Ontario

1998 350 33%IDU 73%

Non-IDU 9.6%


Selected seroepidemiologic Selected seroepidemiologic studies among patient studies among patient populationspopulations

Author Population Location Study year

Sample size

HCV prevalence

Romanowski Non-IDUs STD clinic

Alberta 1994-95 6,668 0.89% Men 1.2%

Women 0.54%

Ali Hemophilia patients

Newfoundland 1990? 66 33% 83% FCs <

1996

Manuel Patients in HBV outbreak

Metro Toronto

1996 6,055 0.7% (standardized)

Armstrong Cornea donors

Ontario 1993-96 3,228 0.93%

Scully Sexual partners of HCV+

Ottawa, Ontario

1992? 29 0.00%


Selected seroepidemiologic Selected seroepidemiologic studies among variousstudies among variouspatient populationspatient populations

Author Population LocationStudyyear

Samplesize

HCVprevalence

Louie Hospitalpatients

Toronto,Ontario

1990 3,000 0.54%

Joly Sentinelhospital daysurgery pts

Quebec 1990-92 10,164 0.58%Men 0.55%

Women 0.60%

Pi Pregnantwomen

BritishColumbia

1994 15,000 0.9%

Craib MSM Vancouver,BritishColumbia

1982-98 623 5.9%IDU 49%

Non-IDU 3.1%


Hepatitis C infection due to Hepatitis C infection due to blood transfusion: Methodsblood transfusion: Methods

Model 1Model 1 For each year, number of transfused For each year, number of transfused units x HCV risk per unitunits x HCV risk per unit

Used survival function to calculate number Used survival function to calculate number of of

recipients surviving to July 1998recipients surviving to July 1998

Model 2Model 2 Estimated number of HCV-infected persons Estimated number of HCV-infected persons in Canada as of July 1998in Canada as of July 1998

Calculated proportion and number due to Calculated proportion and number due to blood transfusionblood transfusion

Model 3Model 3 Estimated number of persons transfused Estimated number of persons transfused in Canadain Canada

Calculated proportion and number with Calculated proportion and number with HCV infectionHCV infection


Modeled HCV risk and number of Modeled HCV risk and number of HCV-infected transfusion HCV-infected transfusion recipients, 1980–1991recipients, 1980–1991

Year of transfusion

HCV risk per unit

HCV risk per episode

Number of HCV

infections

Number surviving to

1998

1980 0.400% 2.1% 4,790 1,560

1981 0.400% 2.1% 5,090 1,720

1982 0.400% 2.1% 5,380 1,880

1983 0.383% 2.1% 5,580 2,020

1984 0.356% 1.9% 5,630 2,110

1985 0.317% 1.7% 5,190 2,010

1986 0.278% 1.5% 4,500 1,800

1987 0.246% 1.3% 3,880 1,600

1988 0.223% 1.2% 3,430 1,460

1989 0.201% 1.1% 3,050 1,340

1990a 0.185% 0.99% 850 390

1990b 0.035% 0.19% 520 250

1991 0.017% 0.09% 320 160


Modeled HCV risk per transfusion Modeled HCV risk per transfusion episode and number of HCV-episode and number of HCV-infected transfusion recipients, infected transfusion recipients, 1980-19911980-1991

0.00%

0.10%

0.20%

0.30%

0.40%

0.50%

1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990a 1990b 1991

Year of transfusion

Per

un

it H

CV

ris

k


Modeled number of surviving Modeled number of surviving HCV-infected transfusion HCV-infected transfusion recipients recipients by period of transfusion,1980–by period of transfusion,1980–19921992

Period oftransfusion

Number oftransfusion-associated

HCV infectionsProportion

of total Plausible limits1960-85 27,700 80% (19,800 - 38,200)

1986-90 6,600 19% (5,200 - 8,100)

1990-92 450 1% (390 - 520)

Total 34,800 100% (26,600 - 45,400)


Modeled number of surviving Modeled number of surviving HCV-infected transfusion HCV-infected transfusion recipients recipients by period of transfusion by period of transfusion (n=34,800)(n=34,800)

1990-921%

1986-8919%

1960-8580%


Modeled number of surviving Modeled number of surviving HCV-infected transfusion HCV-infected transfusion recipients recipients by period of transfusion 1980–by period of transfusion 1980–19921992

0 0.5 1 1.5 2

Rate (/1,000)

Ontario

British Columbia

Quebec

Alberta

Manitoba

Nova Scotia

Saskatchewan

New Brunswick

Newfoundland

PEI

Canada 34,790

50

70

420

630

700

900

3,700

5,290

7,660

15,370


Hepatitis C prevalence and Hepatitis C prevalence and incidence, 1998: Methodsincidence, 1998: Methods

From HCV transfusion Model 2, From HCV transfusion Model 2, estimated prevalent HCV infectionsestimated prevalent HCV infections

Interpolated to each provincesInterpolated to each provinces

Using population-based data (limited)Using population-based data (limited)

Estimating relative population prevalence Estimating relative population prevalence from first-time blood donorsfrom first-time blood donors


Modeled number of HCV-infected Modeled number of HCV-infected persons by province, 1998 persons by province, 1998 (n=(n=240,000)240,000)

0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40%

HCV Prevalence

Ontario

British Columbia

Quebec

Alberta

Manitoba

Nova Scotia

Saskatchewan

New Brunswick

Newfoundland

PEI 340

460

2,800

4,300

4,800

6,200

25,400

36,200

52,500

105,200


Modeled number of Modeled number of HCV-infected persons HCV-infected persons by province (n=by province (n=240,000)240,000)

22.0%

1.8%

1.2%

0.2%

0.1%

2.0%

2.6% 10.7%

15.2%

44.2%

OntarioBritish ColumbiaQuebecAlbertaManitobaNova ScotiaSaskatchewanNew BrunswickNewfoundlandPEI


HypotheticalHypothetical number of number of HCV-infected persons in Canada HCV-infected persons in Canada by mode of transmissionby mode of transmission

Mode oftransmission Number at risk

HCVprevalence

HCVnumber

Proportion(%) Plausible limits

Transfusionrecipients

2,700,000 1.3% 35,000 15%

Active IDUs 90,000 75% 68,000 28%

Ex-IDUs 180,000 40% 72,000 30%

Total IDUs 270,000 52% 140,000 58%

Other 27,000,000 0.24% 65,000 27%

Total 30,000,000 0.80% 240,000 100% (215,000 - 275,000)


Annual incidence of Annual incidence of HCV infection in Canada:HCV infection in Canada:Preliminary perspectivesPreliminary perspectives

Method 1Method 1 Observed incidence among Observed incidence among populations in populations in

sentinel surveillance study projected sentinel surveillance study projected from from

proportion symptomatic to all HCV proportion symptomatic to all HCV infectionsinfections

Method 2Method 2 Observed HCV incidence Observed HCV incidence among among susceptible susceptible IDUs in study IDUs in study cohorts cohorts projected from proportion projected from proportion IDU to all IDU to all HCV infections HCV infections

(90,000 IDU - 68,000 HCV) x 20%(90,000 IDU - 68,000 HCV) x 20%

Preliminary estimate: 3,000 - 8,000 new Preliminary estimate: 3,000 - 8,000 new HCV infections per year HCV infections per year


HCV infections in Canada:HCV infections in Canada:InterpretationInterpretation Estimates are subject to considerable Estimates are subject to considerable

uncertainty due to very limited Canadian uncertainty due to very limited Canadian data from representative study populations data from representative study populations (only one study, in Quebec)(only one study, in Quebec)

HCV prevalence appears highest in British HCV prevalence appears highest in British Columbia, Ontario and Alberta. Four Columbia, Ontario and Alberta. Four provinces, British Columbia, Ontario, provinces, British Columbia, Ontario, Quebec and Alberta account for ~92% of Quebec and Alberta account for ~92% of HCV infections in CanadaHCV infections in Canada

The majority (>50%) of prevalent HCV The majority (>50%) of prevalent HCV infections in Canada are among IDUs, where infections in Canada are among IDUs, where HCV prevalence is >100-fold greater than HCV prevalence is >100-fold greater than other Canadians taken as a wholeother Canadians taken as a whole


Estimating the number of persons Estimating the number of persons in in Canada with dual HCV-HIV Canada with dual HCV-HIV infection:infection:MethodsMethods

1. Estimate the number of HIV-infected 1. Estimate the number of HIV-infected persons by HIV-defined exposure category persons by HIV-defined exposure category and geographic regionand geographic region

2.2. Estimate HCV prevalence in each group Estimate HCV prevalence in each group (obtain data from available studies and (obtain data from available studies and review by expert consensus panel)review by expert consensus panel)

3.3. Multiply number by HCV prevalenceMultiply number by HCV prevalence

4.4. Plausible limits of outcome using Monte Plausible limits of outcome using Monte Carlo simulationCarlo simulation

5.5. Special analysis for Aboriginal population Special analysis for Aboriginal population and prisoners to estimate persons in each and prisoners to estimate persons in each HIV-defined exposure category and then as HIV-defined exposure category and then as aboveabove


Modeled number of HCV-HIV Modeled number of HCV-HIV infected persons by exposure infected persons by exposure category, 1999category, 1999

MSM MSM-IDU IDU EndemicOtherhetero

Clottingfactors Transfused

Total

Number 1,193 1,648 7,921 63 118 237 15 11,194

Proportion 11% 15% 71% 0.6% 1.1% 2.1% 0.1% 100%

Lower 95%limit

760 1,200 6,300 41 56 190 11 9,400

Upper 95%limit

1,800 2,200 9,900 88 220 300 21 13,300


Modeled number of HCV-HIV Modeled number of HCV-HIV infected persons by exposure infected persons by exposure category, 1999 (n=11,194)category, 1999 (n=11,194)

15%

0.1%2.1%

1.1%0.6%

71%

11%

MSM

MSM-IDU

IDU

Endemic

Other hetero

Clottingfactors

Transfusion


Modeled number of HCV-HIV Modeled number of HCV-HIV infected persons by geographic infected persons by geographic region, 1999 (n=11,194)region, 1999 (n=11,194)

34%

1.0%1.7%

3.3%

6.8%

29%

25%

Ontario

Quebec

British Columbia

Alberta

Prairies

Atlantic

Yukon / NWT


Modeled number of HCV-HIV Modeled number of HCV-HIV infected Aboriginal people infected Aboriginal people by exposure category, 1999by exposure category, 1999 (n=(n=1,477)1,477)

10%

87%

1.8%

0.2%0.4%

0.9%

MSM

MSM-IDU

IDU

Other hetero

Clotting factors

Transfusion


Modeled number of HCV-HIV Modeled number of HCV-HIV infected prisoners infected prisoners by exposure category, 1999 by exposure category, 1999 (n=611)(n=611)

11%

88%

0.6%0.0%

0.0%

0.9%0.0%

MSMMSM-IDUIDUEndemicOther heteroClottingfactorsTransfusion


ConclusionsConclusions

Current estimates of HCV infections must be Current estimates of HCV infections must be considered as hypotheses, not as conclusions; considered as hypotheses, not as conclusions; the epidemiology of HCV infection in Canada the epidemiology of HCV infection in Canada remains largely unknown. remains largely unknown.

Population-based studies are necessaryPopulation-based studies are necessary

Burden of HCV infection is greatest in four Burden of HCV infection is greatest in four provinces which account for most HCV infections provinces which account for most HCV infections in Canadain Canada

Most new HCV infections are probably among Most new HCV infections are probably among IDUs but a substantial proprtion, possibility as IDUs but a substantial proprtion, possibility as many as 40%, are not related to injectionmany as 40%, are not related to injection

Transmission of HCV (probability, determinants) Transmission of HCV (probability, determinants) in other populations needs further elucidationin other populations needs further elucidation

Epidemiology of Hepatitis C Infection in Canada Robert S. Remis MD, MPH, FRCPC Department of Public...

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