HIV/AIDS Epidemiology
Update
February 2009
Dr Nigel Dickson
Director, AIDS Epidemiology Group
Department of Preventive and Social Medicine
University of Otago, Dunedin
Update data on HIV diagnoses through
antibody testing
• 2008 figures and trends – 1999-2008
• New analyses
– Ethnicity
– “Late testers”
• Mention new project
– Follow up questionnaires
2008 figures and trends in people
diagnosed with HIV through antibody
testing – 1999-2008
Care with data …
• Year of diagnosis not infection
• Not all infected in New Zealand will have been
diagnosed
• Some infected people (most diagnosed initially
overseas) do not have an antibody test in NZ
– the data on these people captured through viral
load testing
Diagnosed HIV – through antibody testing
– by year of test
Unknown
200
Perinatal
180
Other
IDU
160
140
Heterosexual contact
Homosexual contact
120
100
80
60
40
20
0
85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05
Year of Diagnosis
06 07 08
Annual number of men diagnosed, infected
through homosexual contact (MSM)
100
90
80
70
60
50
40
30
20
10
0
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
MSM diagnosed with HIV – 1999-2008
Place of infection
Place of residence at diagnosis
70
70
60
60
50
50
40
NZ
40
30
Overseas
30
20
Unk
20
Auckland
10
10
Age at diagnosis
2008
2007
2006
2005
2004
2003
2002
2001
1999
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
2000
0
0
Ethnicity
70
70
60
60
50
15-19
40
20-29
40
30
30-39
30
20
40-49
20
50+
10
Europ
50
Maori
PI
Asian
African
10
Other
2008
2007
2006
2005
2004
2003
2002
2001
2000
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1999
0
0
Other NZ
Overseas/unk
Men and women diagnosed infected through
heterosexual contact
50
45
Men
40
35
Women
30
25
20
15
10
5
0
1999 2000 2001 2002 2003 2004 2005 2006 2007 2008
Heterosexually infected men and women
diagnosed with HIV – 1999-2008
Place of residence at diagnosis
Age at diagnosis
2008
1999
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
0
2007
10
Overseas/unk
2006
Unk
20
Other NZ
2005
Overseas
30
Auckland
2004
NZ
40
2003
50
2002
60
50
45
40
35
30
25
20
15
10
5
0
2001
70
2000
Place of infection
80
Ethnicity
60
50
45
40
35
30
25
20
15
10
5
0
50
30-39
20
40-49
10
Asian
African
Other
2008
2007
2006
2005
2004
2003
0
2002
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
50+
PI
2001
20-29
Maori
30
2000
15-19
Europ
40
1999
<15
International comparison of MSM
diagnosis rates – 2000-6
• Data recently published from 27/30 european
(EU/EFTA ) countries
• Canadian, Australian and US data from
national surveillance reports
Care with data…
• Different patterns of HIV testing may exist
• Rates of diagnosis derived from number of all
men not MSM
HIV diagnosis rate among MSM in major Western European
countries + Australia, Canada, US and New Zealand
160.0
140.0
Australia
Per million men aged
15-64yr
Austria
Belgium
Canada
120.0
France
Germany
100.0
Greece
Ireland
80.0
Italy
Netherlands
60.0
Norway
Portugal
40.0
Spain
Sweden
20.0
Switzerland
United Kingdom
0.0
United States
2000
2001
2002
2003
2004
2005
2006
New Zealand
Ethnicity among people diagnosed
with HIV through antibody testing
• Information collected from clinician
• Recent decade - 1999-2008
Care with data…
• How ethnicity is determined
• Rates of testing
• Relatively small numbers
Numbers of people diagnosed with
HIV by year and ethnicity
90
80
70
Europ
60
Maori
50
PI
40
Asian
African
30
Other
20
Unk
10
0
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
Comparing disease between ethnic
groups 1999-2008
Derive and compare rates
– Numerator from clinician, denominator from
census
We have looked at…
a) …overall comparison of diagnosis rates as an
indication of newly recognised burden in these
populations
b) …comparison of age adjusted rate of diagnosis as
a surrogate of infection risk
Comparison of rates of newly diagnosed HIV among
children and adults by means of infection
0-14yr
MSM (all men
15-59yr men)
Heterosexual
males (all men
15-59yr men)
Number
Relative
Rate and
95% CI
Number
Relative
Rate and
95% CI
Number
Relative
Rate and
95% CI
Heterosexual
Number
females (all
Relative
women 15-59yr Rate and
men)
95% CI
European
Maori
Pacific
Asian
Other
4
6
3
4
30
1.0
(Reference)
4.5
(1.3-16.0)
4.6
(1.0-20.7)
8.9
(2.2-35.8)
527
(185-1500)
631
92
26
59
39
1.0
(Reference)
0.80
(0.64-1.0)
0.49
(0.33-0.72)
0.76
(0.58-1.0)
4.8
(3.5-6.7)
77
10
9
52
149
1.0
(Reference)
0.71
(0.37-1.4)
1.4
(0.69-2.8)
5.5
(3.9-7.8)
150
(114-197)
57
13
15
54
171
1.0
(Reference)
1.2
(0.66-2.2)
3.1
(1.8-5.5)
7.2
(4.9-10.4)
273
(202-368)
Comparison of risks to predict future
disease pattern in New Zealand
• Use diagnosis rates as surrogates for infection rates
• Need to take into account different age structures of
population
– Comparing age standardised rates and report as
standardised incidence ratios + confidence intervals
• Does the rate of infection in New Zealand give a
better indication of likely future trends for infections
here?
– Overall SIRs and 95% CI
– ‘”Infected in New Zealand” SIRs and 95% CI
Standardised incidence ratio + 95% CI
All infections
All
European
Maori
Pacific
Asian
Other
1.0
0.82
(0.67-97)
0.83
(0.63-1.07)
2.O
(1.7-2.2)
42
(38-46)
(Reference)
MSM
Hetero Males
Hetero Females
1.0
0.80
0.48
0.77
(Reference) (0.64-0.97) (0.31-0.71) (0.59-0.98)
1.0
0.75
1.5
(Reference) (0.36-1.14) (0.67-2.8)
1.0
(Reference)
1.2
(0.62-2.0)
2.7
(1.5-4.5)
4.7
(3.4-6.5)
5.9
(4.4-7.7)
154
(130-180)
6.4
(4.8-10.2)
245
(210-284)
Standardised incidence ratio + 95% CI
People infected in New Zealand
All
European
Maori
1.0
1.3
(1.0-1.6)
(Reference)
MSM
1.0
(Reference)
Hetero Males
Hetero Females
1.0
(Reference)
1.0
(Reference)
Pacific
Asian
Other
0.81
0.96
(0.52-1.6) (0.70-1.29)
5.2
(3.2-7.8)
1.2
0.53
0.75
(0.88-1.5) (0.28-0.91) (0.49-1.1)
2.6
(1.2-4.8)
1.5
(0.48-3.5)
1.3
(0.16-4.7)
1.3
(0.27-3.8)
8.1
(1.0-29.3))
2.8
(1.4-5.0)
3.3
(1.2-7.3)
3.6
1.7-6.7)
27
(9.8-58)
Beware of CIs as small number in reference population
Late diagnoses of HIV infection
among adults in New Zealand
“Early” diagnosis of HIV infection allows…
• optimal decision regarding individual’s therapy
• helps in control of spread
– Behaviour change
– Reduction in viral load
“Late” diagnosis doesn’t!
We defined “Late tester” either …
• Diagnosis of AIDS around time of HIV diagnosis
– Within 3/12 of each other
• Initial CD4+ count ‹200 cells per µlitre
Two things influence “late testers” as a
proportion of all diagnoses
• Testing practices
• Dynamics of underlying HIV epidemic
A higher proportion of “Late testers” found if:
(a) Less testing of asymptomatic people
(b) In the late-stage of a declining epidemic
(c) Both
682 HIV diagnoses among adults through
antibody testing 2005-8
(initial CD4 counts first collected here in 2005)
• Initial CD4 count reported for 71% (490/682)
• Of these 30.6% (150/490) “late testers”
Are there different proportions of “late testers”
among people diagnosed by demographic and
other characteristics?
“Late testers” by means of infection - 2005-8
MSM
Heterosexual
Other
Unknown
Total
New
diagnoses
245
217
6
22
490
‘Late
testers’
24.5%
36.9%
33.3%
36.4%
30.6%
OR
1.0
1.8
1.6
CI (95%)
Ref.
1.2-1.7
0.41-11.1
* Adjusted for age
Adj.
OR*
1.0
2.0
1.2
CI (95%)
Ref.
1.34-3.1
0.21-7.1
Late testers among MSM 2005-8
Year
New
diagnoses
127
118
44
85
116
‘Late
testers’
24.4%
24.6%
6.8%
22.4%
32.8%
OR
CI
(95%)
1.0
4.0
6.8
Ref.
1.1-14.5
2.0-23.4
Adj.
OR*
1.0
0.93
CI (95%)
Ref.
0.51-1.7
Age at Diagnosis
2005/6
2007/8
<30
30-39
40+
Ethnicity
European
171
21.1%
1.0
Ref.
Maori
32
40.6%
4.5
1.9-11.0
Pacific
7
28.6%
2.7
0.47-15.1
Other
33
27.3%
1.9
0.79-4.8
185
24.9%
1.0
Ref.
Overseas
55
23.6%
0.94
0.46-1.95
Symptoms
Other
87
154
46.0%
13.0%
5.0
1.0
2.6-9.5
Ref.
Place of infection New Zealand
Reason for
testing
* Adjusted for age
Late testers among heterosexual men and women 2005-8 – work in progress
Year
Gender
Age at Diagnosis
Ethnicity
Place of Infection
Reasons for testing
Total
2005/6
2007/8
Men
Women
<30
30-39
40+
European
Maori
Pacific Island
Other
New Zealand
Overseas
Unknown
Symptoms
Immigration medical
Other
Unknown
New diagnoses
125
92
110
107
47
90
80
40
11
8
158
40
169
8
62
69
81
5
217
“Late testers”
32.8%
42.4%
45.5%
28.0%
27.7%
34.4%
45.0%
42.5%
54.5%
50.0%
33.5%
37.5%
37.3%
25.0%
66.1%
26.1%
19.8%
100.0%
36.9%
Some international comparisons
CD4<200 (+/- clinical late)
Country
Source
Year
NZ†
National
surveillance
France†
Overall
MSM
Hetero
2005-8
30.6%
24.5%
M 46%
F 28%
6 tertiary
centers
2004–5
31.5%
UK and
Ireland*
Info. from
providers
(76% RR)
2006
33%
20%
M 43%
F 36%
Australia†
National
surveillance
2000-6
Est 25%
19.5%
Est. 39%
† CD4<200+clinical late
Hetero>MSM
*CD4<200
New initiative
• Follow up questionnaire with clinician 3/12
post diagnosis
– Up date information
– Check for AIDS diagnosis
– Ask about partner notification
• Clinicians asked to give questionnaire to
patient for him/her to return directly to us
– Circumstances of HIV acquisition (if known)
– Includes the census ethnicity question
Conclusions
• Worrying continuing increased level of new diagnoses
– Safest to assume a reflection of new infections
• Rise in diagnosis rate in New Zealand also seen in most
Western European countries, US, Canada and Australia
between 2000-2006
• Burden of new diagnoses not borne equally but all ethnic
groups
• If diagnosis rate of infections within New Zealand a surrogate
for infection rates no major differences between ethnic groups
among men, but among women relative to European women,
women of “other” ethnic groups, Pacific and Maori women at
greater risk
• Late diagnosis rates slightly higher than Australia and similar to
UK and France
– Among MSM late diagnosis higher among Maori
My recommendations
• Review current of national strategy and action
for HIV prevention + surveillance
• Consider when prevention needs to be
specific for HIV and when it should be part of
general STI prevention
• Improve surveillance of other STIs to identify
risks among MSM
Acknowledgements
•
•
•
•
Organisers and funders of this meeting
Funding of AEG Ministry of Health
Clinicians who provide data
Other members of AEG
– Sue McAllister (Research Officer)
– Charlotte Paul (Epidemiologist)
– Katrina Sharples (Statistician)
– Patricia Priest (Epidemiologist)
www.aidsepigroup.otago.ac.nz/