Uptake of HIV testing among
pregnant women in Ontario:
Results from the
HIV seroprevalence study
to December 2000
Robert S. Remis, Carol Major, Margaret Fearon,
Evelyn Wallace, Peggy Millson, Liviana Calzavara,
Elisabeth Rea, Susan King, Marion Vermeulen and
Elaine Whittingham
Department of Public Health Sciences, University of Toronto
Laboratories Branch, Public Health Branch,
Ontario Ministry of Health and Long Term-Care
Toronto Public Health
Hospital for Sick Children, Toronto
Canadian Association of HIV/AIDS Research
Tenth Annual Scientific Conference
Toronto, Ontario May 31-June 2, 2001
Acknowledgments
• Central Public Health Laboratory,
Ontario Ministry of Health and Long-Term Care
• Keyi Wu, programming
• Mark Fisher, systems consulting and custom download
• Carol Swantee, program support
• Prenatal Screening Evaluation Committee
• Frank McGee, coordinator
• Janis Tripp, consultant
• Funding
• AIDS Bureau, Ontario Ministry of Health
• Bureau of HIV/AIDS, STD & TB, Health Canada
MOHLTC, Laboratories Branch, IMC – 2001
Background
• 1989-91: Ontario HIV seroprevalence study
(Coates et al), 0.23 / 1,000
• February 1994: ACTG 076 showed 67% decrease in
mother-infant HIV transmission
• 1997: Modeled HIV prevalence, 0.70/1,000
and estimated uptake of prenatal HIV testing
1994-96, 20–25%
MOHLTC, Laboratories Branch, IMC – 2001
Ontario screening program
• Spring 1995: Advisory to physicians to
consider HIV testing of pregnant women
• August 1997: Committee formed to plan program
• December 1998: Minister announced program to
offer HIV testing to all pregnant women
• January 1999: Promotional materials and
requisitions sent to physicians
MOHLTC, Laboratories Branch, IMC – 2001
Study objectives
• Quantify and characterize HIV prevalence
among women in Ontario, and
• Evaluate the Ontario universal HIV screening
program
MOHLTC, Laboratories Branch, IMC – 2001
Data management
• Data extracted from Labyrinth
(prenatal and HIV diagnostic)
• Study period Jan 3, 1999 to Dec 30, 2000
• Specimens from prenatal database included only
if no previous specimen in the previous 6 months
• Records for which HIV testing not prescribed
on requisition matched to records in HIV diagnostic
database
• Matching allowed for different spelling and structure
of name (double-barrelled first and last names) and
reversal of month/day in birth date
MOHLTC, Laboratories Branch, IMC – 2001
Data analysis
• Number of women tested at prenatal visit included:
• Women for whom test ordered on prenatal
requisition, and
• Women tested though diagnostic service on same
day as prenatal specimen
• Analysis in SAS of:
• Trends over time in proportion tested
• Testing rates by health region and age group
• HIV-positive women: number and rates by type of
test, region and quarter
MOHLTC, Laboratories Branch, IMC – 2001
Number of prenatal specimens by health region,
January 1999 to December 2000
Toronto
Central East, other
Southwest
Central West
Ottawa
Eastern, other
Northern
N/A or OFP
Total
MOHLTC, Laboratories Branch, IMC – 2001
Number
specimens
76,223
61,409
37,355
40,035
21,133
23,310
18,083
1,335
278,883
Proportion
27%
22%
13%
14%
8%
8%
7%
100%
Number of prenatal specimens and
number testing for HIV by quarter
Prenatal
specimens
Prenatal visit
Diagnostic
service
Proportion
tested
1999
Q1
33,661
31%
12%
43%
Q2
31,578
38%
10%
49%
Q3
34,320
40%
10%
50%
Q4
34,383
40%
10%
50%
133,942
37%
10%
48%
Q1
35,877
40%
11%
50%
Q2
34,115
40%
10%
50%
Q3
37,583
40%
11%
51%
Q4
37,365
40%
12%
52%
144,940
40%
10%
51%
Total 1999
2000
Total 2000
MOHLTC, Laboratories Branch, IMC – 2001
HIV testing among women who
submitted a prenatal specimen
50%
40%
Prena ta l
HIV dia gnostic
Any HIV test
30%
20%
Month (1999- 2000)
MOHLTC, Laboratories Branch, IMC – 2001
Dec
Nov
O ct
Sep
Aug
Jul
Jun
May
Apr
Mar
Feb
Jan
Dec
Nov
O ct
Sep
Aug
Jul
Jun
May
Apr
Mar
0%
Feb
10%
Jan
Proportion of specimens
60%
HIV testing among women who
submitted a prenatal specimen
70
60
50
40
30
Month (1999- 2000)
MOHLTC, Laboratories Branch, IMC – 2001
Dec
Nov
O ct
Sep
Aug
Jul
May
Apr
Mar
Feb
Jan
Dec
Nov
O ct
Sep
Aug
Jul
Jun
May
Apr
Mar
0
Feb
10
Jun
M etro Toronto
Centra l Ea st, other
Southwest
Centra l West
20
Jan
Proportion of specimens (%)
80
HIV testing among women who
submitted a prenatal specimen
70
60
50
40
30
Month (1999- 2000)
MOHLTC, Laboratories Branch, IMC – 2001
Dec
Nov
O ct
Sep
Aug
Jun
May
Apr
Mar
Feb
Jan
Dec
Nov
O ct
Sep
Aug
Jul
Jun
May
Apr
Mar
0
Feb
10
Jul
Otta wa - Ca rleton
Ea stern, other
N orthern
20
Jan
Proportion of specimens (%)
80
Proportion of pregnant women testing for
HIV by health region, last quarter 2000
Toronto
Central East, other
Southwest
Central West
Ottawa
Eastern, other
Northern
N/A or OFP
Total
MOHLTC, Laboratories Branch, IMC – 2001
Number of
women
9,866
8,110
4,860
6,234
2,790
2,913
2,395
197
37,365
HIV tested
4,917
4,221
2,543
2,685
1,727
1,698
1,426
94
19,311
Proportion
tested
50%
52%
52%
43%
62%
58%
60%
48%
52%
Number of PHUs in each region by
proportion of HIV testing, last quarter 2000
Number of PHUs by proportion of HIV testing uptake
20-29%
30-39%
40-49%
50-59%
60-69%
Toronto
1
Central East,
other
1
4
1
2
3
1
1
1
6
Southwest
1
Central West
1
Northern
Total
1
1
MOHLTC, Laboratories Branch, IMC – 2001
4
11
6
1
9
7
Ottawa
Eastern,
other
70-79%
Total
PHUs
1
1
2
3
5
3
2
2
8
10
8
3
37
Number of HIV-positive women
Prenatal screening
Previously
diagnosed
Total
HIV+
HIV+
HIV+
1999
Q1
Q2
Q3
Q4
2
3
3
1
2
2
2
2
4
5
5
3
9
8
17
3
5
11
4
2
1
1
3
5
6
12
7
Total 2000
23
7
30
Both years
32
15
47
Total 1999
2000
Q1
Q2
Q3
Q4
MOHLTC, Laboratories Branch, IMC – 2001
Ra te (per 1,000)
HIV-positivity rates by time of
diagnosis and quarter
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
Prena ta l screening
Previously dia gnosed
Q1
1999
Q2
Q3
Q4
Q1
2000
Period
MOHLTC, Laboratories Branch, IMC – 2001
Q2
Q3
Q4
HIV-positivity rates (per 1,000)
by time of diagnosis and period
Jan 1999 to
Mar 2000
rate
HIV+ identified through:
Prenatal
0.20
screening
Previous
0.47
diagnosis
Total
MOHLTC, Laboratories Branch, IMC – 2001
0.27
Apr to Dec
2000
rate
Relative
risk
p-value
0.45
2.32
0.028
0.40
0.87
NS
0.44
1.67
0.015
HIV-positivity rates (per 1,000) by
health region and period for
diagnoses at prenatal screening
Region
Northern
Ottawa
Eastern, Other
Toronto
Central East, Other
Central West
Southwest
Total
MOHLTC, Laboratories Branch, IMC – 2001
Jan 1999 to
Mar 2000
0.20
0.57
0.00
0.39
0.00
0.14
0.11
0.20
Apr to Dec
2000
0.00
0.76
0.25
0.91
0.41
0.33
0.00
0.45
Relative
risk
0.00
1.33
Infinite
2.30
Infinite
2.32
0.00
p-value
NS
NS
NS
NS
0.029
NS
NS
Interpretation
• Actual uptake of HIV testing may be higher due to
false non-matches (e.g. anonymous HIV testing)
• Study does not indicate why uptake is less than
ideal (qualitative research of pregnant women and
physician survey are under way)
• Study does not indicate number of HIV-infected
women undiagnosed
• Unlinked component of HIV seroprevalence study
among women not HIV tested is critical
• This component has been delayed for almost two
years by Ministry
MOHLTC, Laboratories Branch, IMC – 2001
Conclusions
• Critical to capture data from HIV diagnostic
database as well as from prenatal database
• HIV testing increased from 38% to 49% from
January to May 1999, with modest increase since
• Important regional differences in HIV test uptake
• Over 2 years, 47 women identified as HIV-positive,
13 previously diagnosed, 32 newly diagnosed
• Data suggests more high risk pregnant women are
being offered and accepting HIV testing
MOHLTC, Laboratories Branch, IMC – 2001
Conclusions
• According to model (not presented)
• Birth rate among diagnosed HIV-infected women
is very low
• ~50% of HIV-infected women undiagnosed at
conception remain undiagnosed
• Approximately 6–8 preventable mother-infant
transmissions occur annually
MOHLTC, Laboratories Branch, IMC – 2001