trends in hiv incidence in ontario based on the detuned assay: update to october 2000 robert s....

Trends in HIV incidence in Trends in HIV incidence in Ontario based on the Ontario based on the detuned assay: Update to detuned assay: Update to October 2000October 2000

Robert S. Remis, Carol Major, Carol Swantee, Robert S. Remis, Carol Major, Carol Swantee, Margaret Fearon, Evelyn Wallace, Elaine Margaret Fearon, Evelyn Wallace, Elaine WhittinghamWhittinghamDepartment of Public Health Sciences, University of TorontoDepartment of Public Health Sciences, University of Toronto

HIV Laboratory, Laboratory Services, HIV Laboratory, Laboratory Services, Ontario Ministry of Health and Long-Term CareOntario Ministry of Health and Long-Term Care

Public Health Branch, Public Health Branch, Ontario Ministry of Health and Long-Term CareOntario Ministry of Health and Long-Term Care

Canadian Association of HIV/AIDS ResearchCanadian Association of HIV/AIDS Research10th Annual Scientific Conference10th Annual Scientific ConferenceToronto, Ontario, May 31-June 3, 2001Toronto, Ontario, May 31-June 3, 2001

MOHLTC, Laboratories Branch, IMC – 2001

AcknowledgementsAcknowledgements• At the HIV LaboratoryAt the HIV Laboratory

• Lisa Santangelo and Cindi Farina, data Lisa Santangelo and Cindi Farina, data collectioncollection

• Lynda Healey, detuned assayLynda Healey, detuned assay• Elaine McFarlane, data entry screens Elaine McFarlane, data entry screens • Len Neglia, mailout of questionnairesLen Neglia, mailout of questionnaires

• Regional PHLs, mailout of questionnairesRegional PHLs, mailout of questionnaires• Physicians who prescribe HIV testing, Physicians who prescribe HIV testing,

supplementary datasupplementary data• Ontario HIV Treatment Network, fundingOntario HIV Treatment Network, funding


IntroductionIntroduction• Serodiagnostic data may useful for Serodiagnostic data may useful for

surveillancesurveillance• However,However,

• persons who test may not be representativepersons who test may not be representative• data quality inconsistentdata quality inconsistent

• True HIV incidence and HIV prevalence cannot True HIV incidence and HIV prevalence cannot

be derived directly from databe derived directly from data


IntroductionIntroduction• Testing of HIV-positive specimens using Testing of HIV-positive specimens using

less sensitive (“detuned”) assay permits less sensitive (“detuned”) assay permits the identification of persons who recently the identification of persons who recently seroconverted (< 4 months) seroconverted (< 4 months)

• Allows calculation of HIV incidence density, an Allows calculation of HIV incidence density, an important indicator usually difficult to important indicator usually difficult to measuremeasure


Study objectivesStudy objectives• To accurately determine the number of To accurately determine the number of

persons newly testing positive for HIV persons newly testing positive for HIV • To determine the distribution of exposure To determine the distribution of exposure

category among newly diagnosed HIV-category among newly diagnosed HIV-infected personsinfected persons

• To estimate HIV incidence density among To estimate HIV incidence density among persons undergoing HIV testing persons undergoing HIV testing


Data collection and managementData collection and management• Questionnaire sent with HIV-positive results Questionnaire sent with HIV-positive results

and 1:200 sample of HIV-negative resultsand 1:200 sample of HIV-negative results• Data on risk factors for HIV infection and Data on risk factors for HIV infection and

HIV test historyHIV test history• Questionnaire may be returnedQuestionnaire may be returned

• by mail or faxby mail or fax• by telephone interviewby telephone interview

• Data entered in Microsoft AccessData entered in Microsoft Access


Laboratory methodsLaboratory methods• Abbott 3A11 EIA kit modified as follows:Abbott 3A11 EIA kit modified as follows:

• serum diluted to 1:20,000serum diluted to 1:20,000• incubation period reduced to 30 minutesincubation period reduced to 30 minutes• cut-off value increased cut-off value increased


Study questionnaires mailed and Study questionnaires mailed and returned, Oct 1999 to Dec 2000returned, Oct 1999 to Dec 2000

QuestionnairesQuestionnairesKaplan - Meier Kaplan - Meier

returned byreturned by

MailedMailed ReturnedReturned ProportionProportion 4 mon.4 mon. 8 mon.8 mon.

HIV-positiveHIV-positive

HIV-negativeHIV-negative

TotalTotal

1,071 1,071

1,392 1,392

2,463 2,463

733 733

1,001 1,001

1,734 1,734

68%68%

72%72%

70%70%

72%72%

73%73%

79%79%

80%80%


Exposure category classification according Exposure category classification according to to HIV test requisition, returned questionnaires HIV test requisition, returned questionnaires and modeled distribution, HIV-positives and modeled distribution, HIV-positives

HIV test HIV test requisitionrequisition

Returned Returned questionnaires questionnaires

of NIRof NIRProjected finalProjected final

distributiondistribution

MSMMSM

MSM-IDUMSM-IDU

IDUIDU

EndemicEndemic

HR heteroHR hetero

LR heteroLR hetero

OtherOther

NIRNIR

307 307

15 15

68 68

33 33

30 30

7979

11 11

528 528

57%57%

3%3%

13%13%

6%6%

6%6%

15%15%

2%2%

115115

66

3030

6565

2121

6666

44

221221

37%37%

2%2%

10%10%

21%21%

7%7%

21%21%

1%1%

505 505

25 25

120 120

145 145

66 66

193193

18 18

47%47%

2%2%

11%11%

14%14%

6%6%

18%18%

2%2%

TotalTotal 1,0711,071 528528 100%100% 1,0711,071 100%100%

%NIR%NIR 49%49% 42%42%


HIV-negativesHIV-negatives

HIV test requisitionHIV test requisition

Returned Returned questionnaires questionnaires

of NIRof NIR

Projected finalProjected final

distributiondistribution

MSMMSM

MSM-IDUMSM-IDU

IDUIDU

EndemicEndemic

HR heteroHR hetero

LR heteroLR hetero

OtherOther

NIRNIR

43 43

4 4

31 31

4 4

42 42

404404

46 46

818 818

7%7%

1%1%

5%5%

1%1%

7%7%

70%70%

8%8%

1414

11

2121

1818

2222

404404

1515

323323

3% 3%

0%0%

4%4%

4%4%

4%4%

82%82%

3%3%

66 66

6 6

66 66

34 34

78 78

1,0721,072

71 71

5%5%

0%0%

5%5%

2%2%

6%6%

77%77%

5%5%

TotalTotal 1,392 1,392 818818 1,3921,392 100%100%

%NIR%NIR 59%59% 39%39%


Previous testing history among Previous testing history among "first-time" positive diagnoses"first-time" positive diagnoses

PreviouslyPreviouslytested in:tested in:

Previous test resultPrevious test result

TotalTotalPositivePositive NegativeNegative

OntarioOntario

OtherOther

95.195.1

91.3 91.3

373.5 373.5

68.2 68.2

468.6 468.6

159.5 159.5

TotalTotal 186.4 186.4 441.7 441.7 628.1 628.1

No previous testNo previous test 442.9442.9

Total "first-time" positivesTotal "first-time" positives 1,071.01,071.0

Proportion of “first-time” positives who Proportion of “first-time” positives who have had a previous positive in Ontario have had a previous positive in Ontario 8.9%8.9%


HIV incidence (per 100 person-HIV incidence (per 100 person-years) for selected exposure years) for selected exposure categories by health regioncategories by health region

TorontoToronto OttawaOttawa Rest of OntarioRest of Ontario OverallOverall

TestedTested IncidenceIncidence Tested Tested IncidenceIncidence TestedTested IncidenceIncidence TestedTested IncidenceIncidence

MSMMSM

MSM-IDUMSM-IDU

IDUIDU

HR heteroHR hetero

LR heteroLR hetero

6,987 6,987

112 112

3,725 3,725

4,916 4,916

78,394 78,394

3.93.9

8.38.3

0.790.79

0.180.18

0.040.04

2,487 2,487 30 30

1,193 1,193

1,706 1,706

23,157 23,157

0.170.17

29.4 29.4

1.51.5

0.180.18

0.020.02

3,893 3,893

574 574

8,035 8,035

6,644 6,644

110,663 110,663

1.51.5

0.620.62

0.76 0.76

0.440.44

0.030.03

13,367 13,367

716 716

12,953 12,953

13,265 13,265

212,214 212,214

2.52.5

3.03.0

0.840.84

0.310.31

0.030.03


HIV incidence for selected HIV incidence for selected exposure exposure categories by health regioncategories by health region

0 5 10 15 20 25 30

HIV incidence (per 100 py)

MSM

MSM-IDU

IDU

HR hetero

LR hetero Rest of OntarioOttawaToronto


HIV incidence (per 100 person-HIV incidence (per 100 person-years) among IDU, years) among IDU, by health region and sexby health region and sex

Males Females Overall

ID (95% CI) ID (95% CI) ID (95% CI)

Toronto 0.99 (0.47, 2.1) 0.59 (0.23, 1.55) 0.79 (0.44, 1.44)

Ottawa 1.3 (0.51, 3.1) 3.1 (0.85, 11) 1.5 (0.72, 3.3)

Rest of Ontario 1.0 (0.65, 1.6) 0.30 (0.11, 0.86) 0.76 (0.50, 1.1)

Ontario 1.0 (0.73, 1.5) 0.51 (0.27, 0.97) 0.84 (0.61, 1.1)


HIV incidence (per 100 person-HIV incidence (per 100 person-years) among HR heterosexuals, years) among HR heterosexuals, by health region and sexby health region and sex

Males Females Overall

ID (95% CI) ID (95% CI) ID (95% CI)

Toronto 0.05 (0.0, 0.73) 0.25 (0.08, 0.75) 0.18 (0.06, 0.52)

Ottawa 2.83 (0.53, 15) 0.0 (0.0, 0.68) 0.18 (0.03, 0.97)

Rest of Ontario 1.26 (0.63, 2.5) 0.16 (0.05, 0.48) 0.44 (0.24, 0.80)

Ontario 0.72 (0.38, 1.4) 0.16 (0.07, 0.36) 0.31 (0.19, 0.52)


HIV incidence by quarter, MSMHIV incidence by quarter, MSM

0.0

1.0

2.0

3.0

4.0

5.0

6.0

1999-Q4 2000-Q1 2000-Q2 2000-Q3

Quarter

HIV

inci

dence

(per

100 p

y)

TorontoOttawaRest of Ontario


HIV incidence by quarter, MSM-IDUHIV incidence by quarter, MSM-IDU

0

5

10

15

20

25

30

35

40

1999-Q4 2000-Q1 2000-Q2 2000-Q3

Quarter

HIV

inci

dence

(per

100 p

y) TorontoOttawa

Rest of Ontario


HIV incidence by quarter, IDU HIV incidence by quarter, IDU

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

1999-Q4 2000-Q1 2000-Q2 2000-Q3

Quarter

HIV

inci

dence

(per

100 p

y)

Toronto

OttawaRest of Ontario


HIV incidence by age group, HIV incidence by age group, selected exposure categoriesselected exposure categories

0.0

1.0

2.0

3.0

4.0

5.0

6.0

15-24 25-29 30-34 35-39 40-44 45-49 50+

Age Group

HIV

inci

dence

(p

er

100 p

y)

MSMIDULR hetero


Summary of findingsSummary of findings• Exposure category distribution among those Exposure category distribution among those

with risk factor data not representative with risk factor data not representative • ~9% of persons with an apparent first HIV-~9% of persons with an apparent first HIV-

positive test were previously tested in Ontariopositive test were previously tested in Ontario• Trends in HIV incidence Trends in HIV incidence

• MSM: highest in Toronto but decreasing; MSM: highest in Toronto but decreasing; low and stable in Ottawa; intermediate low and stable in Ottawa; intermediate elsewhere but increasingelsewhere but increasing

• IDU: high in Ottawa; lower elsewhereIDU: high in Ottawa; lower elsewhere• Incidence apparently not higher in younger Incidence apparently not higher in younger

personspersons


InterpretationInterpretation

• Number of discordant samples and HIV tests Number of discordant samples and HIV tests by exposure category modeled by exposure category modeled

• Interpretation of HIV incidence must Interpretation of HIV incidence must incorporate knowledge of patterns in HIV test incorporate knowledge of patterns in HIV test seeking behavioursseeking behaviours

• Observed HIV incidence likely higher than for Observed HIV incidence likely higher than for population population


ConclusionsConclusions

• HIV serodiagnostic program extremely useful HIV serodiagnostic program extremely useful for HIV surveillance for HIV surveillance

• Due to important problems in missing and Due to important problems in missing and unrepresentative data on risk factors and HIV unrepresentative data on risk factors and HIV test history, available data must be enhanced test history, available data must be enhanced through supplementary means on an ongoing through supplementary means on an ongoing basisbasis

• Detuned assay provides a critical indicator of Detuned assay provides a critical indicator of trends in the epidemic at low costtrends in the epidemic at low cost

trends in hiv incidence in ontario based on the detuned assay: update to october 2000 robert s....

Documents

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