1. HIV System Assessment with Longitudinal Treatment Cascade in KwaZulu-Natal, South Africa
Noah Haber,1 Frank Tanser,2 Kevindra Naidu,2 Tinofa Mutevedzi,2 Deenan Pillay,2 Till Bärnighausen1,2
1 Harvard T.H. Chan School of Public Health
2 Wellcome Trust Africa Centre for Health and Population Studies
HIV cascade is a key conceptual tool for understanding the pathway an HIV infected individual travels to go from infection all the way back to good health.

2. Introduction – Treatment cascade
Global ART coverage increasing
63% ART coverage in developing world among eligibles (WHO 2013)
Treatment cascade
Assessment tool for health systems
Identification of gaps and barriers
Staged pathway from infection to immunological recovery
Limitations of standard cross-sectional treatment cascade
Multiple sources of data
Longitudinal analysis limited to post-linkage to care
Strong temporality assumptions
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HIV System Assessment with Longitudinal Treatment Cascade in KwaZulu-Natal, South Africa

3. Setting and data Setting Dataset ARTemis KwaZulu-Natal, South Africa
Semi-rural, low income (Tanser, Hosegood, Bärnighausen, Herbst, Nyirenda, Muhwava, Newell, Viljoen, Mutevedzi, Newell IJE 2008)
High HIV prevalence, ~30% (Zaidi, Grapsa, Tanser, Newell, Bärnighausen AIDS 2013)
HIV incidence, ~3 per 100 person-years (Bärnighausen, Tanser, Gqwede, Mbizana, Herbst, Newell AIDS 2008)
Dataset
Africa Centre Demographic Information System (ACDIS)
ARTemis
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HIV System Assessment with Longitudinal Treatment Cascade in KwaZulu-Natal, South Africa

4. “Cross-sectional” treatment cascade
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HIV System Assessment with Longitudinal Treatment Cascade in KwaZulu-Natal, South Africa

5. “Cross-sectional” vs. “longitudinal” treatment cascade
24,000 person-years
Mean follow-up time
4.6 years
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HIV System Assessment with Longitudinal Treatment Cascade in KwaZulu-Natal, South Africa

6. Longitudinal treatment cascade (I)
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HIV System Assessment with Longitudinal Treatment Cascade in KwaZulu-Natal, South Africa

7. Longitudinal treatment cascade (II)
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HIV System Assessment with Longitudinal Treatment Cascade in KwaZulu-Natal, South Africa

8. Discussion Focus on major cascade losses Population changes over time
Program changes over time
UNAIDS by 2020
Next steps
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HIV System Assessment with Longitudinal Treatment Cascade in KwaZulu-Natal, South Africa

9. Thank you Africa Centre community
Africa Centre fieldwork and clinical staff
Till Bärnighausen
Deenan Pillay
Kobus Herbst
Günther Fink
Funding: Wellcome Trust (Africa Centre), NIH/NICHD (R01 TB)
Works cited
WHO, Global Update on HIV Treatment 2013: Results, Impact, and Opportunities. 2013, World Health Organization.
Tanser, Hosegood, Bärnighausen, Herbst, Nyirenda, Muhwava, Newell, Viljoen, Mutevedzi, Newell. Cohort Profile: Africa Centre Demographic Information System (ACDIS) and population-based HIV survey. Int J Epidemiol, (5): p
Zaidi, Grapsa, Tanser, Newell, Bärnighausen. Dramatic increase in HIV prevalence after scale-up of antiretroviral treatment. Aids, (14): p
Bärnighausen, Tanser, Gqwede, Mbizana, Herbst, Newell AIDS High HIV incidence in a community with high HIV prevalence in rural South Afria: findings from a prospective population-based study. AIDS, (1): p
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HIV System Assessment with Longitudinal Treatment Cascade in KwaZulu-Natal, South Africa

10. Appendix 1:Treatment cascade stages
Event
Definition
First test positive
Definition: First positive HIV test Estimation: First recorded positive HIV test in the ACDIS surveillance system
Knows status
Definition: Patient knows positive HIV status
Estimation: First time patient says he/she knows status, or subsequent event
Linked to care
Definition: Patient engages with formal HIV-related health care
Estimation: First recorded HIV clinic visit, registration at a clinic, CD4 test, viral load count, or initiate ARTs
Eligible for ART
Definition: Patient qualifies for ARTs, based on official guideline
Estimation: Has CD4 count defined below
Pre April 2010: CF4 count < 200 (or pregnant / TB)
April 2010-July 2011: CF4 count < 200 (or pregnant/TB w/ CD4 < 350)
August 2011 and after: CD4 count < 350
Initiate ARTs
Definition: Initiation date of ART
Estimation: Initiation date of ART
Immunological recovery
Definition: Virological suppression and/or immunological recovery
Estimation: Recovery is estimated as having a CD4 count > 500 or a viral load undetectable levels
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HIV System Assessment with Longitudinal Treatment Cascade in KwaZulu-Natal, South Africa

11. Appendix 2: descriptive statistics
First tested positive
All
Female
0.73
0.71
0.74
(0.45)
(0.44)
Years of education
8.1
7.9
8.4
(3.6)
(3.8)
(3.7)
(3.4)
Married ever
0.27
0.3
0.26
0.25
(0.46)
(0.43)
Currently employed
0.31
0.34
0.29
(0.47)
Pregnant ever
0.83
0.82
0.84
(0.38)
(0.36)
First CD4 Count
299
270
305
309
(222)
(212)
(230)
(220) N
5,205
1,712
1,575
1,918
Note: mean (SD)
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HIV System Assessment with Longitudinal Treatment Cascade in KwaZulu-Natal, South Africa

12. Appendix 3: Status at first HIV+ detected
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HIV System Assessment with Longitudinal Treatment Cascade in KwaZulu-Natal, South Africa

13. Appendix 4: Continuous cascade
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HIV System Assessment with Longitudinal Treatment Cascade in KwaZulu-Natal, South Africa

14. Appendix 5: Cont. cascade w/ intercepts
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HIV System Assessment with Longitudinal Treatment Cascade in KwaZulu-Natal, South Africa