INTRODUCTION

1. Point-of-care CD4 tests can increase life-years saved with reduced costs compared to flow cytometric CD4 counting C.L. Grundy1, A. Medina Lara2, D. Winogron3, A.P. Croucher3, H.-G. Batz3, T.B. Hallett1and S.D. Reid3 1Imperial College London, London, United Kingdom, 2Bocconi University, Milan, Italy, 3Imperial College London, CD4 Initiative, London, United Kingdom

2. INTRODUCTION • Initiating ART optimal with CD4 count • Large number start ART without benefit of CD4 • Current WHO guidelines indicate starting ART at 350 cells/mm3 • Not all countries follow this recommendation • Trend for higher CD4 counts in high-income countries • Gold standard CD4 counting = flow cytometry (BD or Beckman) • Flow cytometric CD4 counting not widespread in low-income countries • Infrastructure and costs for rural areas difficult to achieve

3. POINT-OF-CARE CD4 TESTS • CD4 Initiative established in 2005 to develop rapid, economical, point-of-care tests for CD4. • Aim to develop tests which require limited/no infrastructure • No electronics, simple to use, cheap, to initiate ART • Start ART with CD4 count = better outcomes • POC CD4 count = decentralised test • May improve retention to care in ART programmes • Reduce time to ART • Reduce loss to follow up

4. POINT-OF-CARE CD4 TESTS • New generation of point-of-care CD4 tests available • Alere’s PIMA already in use • Others coming in the next 12-24 months • Zyomyx, Inc (from CD4 Initiative programme) • Daktari

5. Impact of POC CD4 tests • Widespread introduction of POC CD4 tests is expected in next 12-24 months • Impact of introduction is not obvious • Before results of clinical trials, useful to address potential impact using mathematical modelling

6. AIMS • To look at impact on Life Years Saved (LYS) of syndromic management and 2 CD4 counting strategies, flow cytometry and point-of-care CD4 tests, on a model of ART initiation • Examine total costs associated with each strategy.

7. METHOD

8. Model • Work presented here is based on a model of ART initiation of Hallett et al, 2008. • Added in costs for CD4 counting technologies • Represents diagnosis, disease progression, clinical monitoring and associated costs • Varied fraction of women referred from ANC and those from VCT Hallett TB, Gregson S, Dube S, Garnett GP. The impact of monitoring HIV patients prior to treatment in resource-poor settings: insights from mathematical modelling. PLOS Med 2008: 5(3)

9. PARAMETERS • Adjusted cost and loss-to-follow up parameters in model • Used 2 different ART initiation thresholds • 250 and 350 • Several different CD4 count costs recorded

10. CD4 COSTS • 2 flow CD4 costs and 2 POC CD4 costs were calculated: • Costs of reagents/test price • Staffing/personnel needed to carry out the test • Infrastructure/laboratory costs (if needed) • Overhead for hospital/laboratory (if needed) • Based calculations on time & motion studies and on reported CD4 costs (Zimbabwe and Uganda) • Arrived at fully-loaded test price

11. CD4 COUNT COST MAKE UP

12. CD4 COSTS These are estimated costs based on these 2 different CD4 counting strategies

13. RESULTS Initiating ART with POC CD4 tests increases life-years saved

16. IMPACT AND COSTS Life years saved SYNDROMIC Costs/LYS

17. COSTS AND COSTS/LYS

18. CONCLUSIONS • POC CD4 testing more effective than flow cytometry (70% versus 52% increase in life years saved) • Flow cytometry tended to greatest overall costs • POC CD4 similar costs/LYS to syndromic management • POC CD4 testing costs could be a more cost-effective strategy.

19. NEXT STEPS • Look at budget impact analysis on a macro level • Refine LFU using more appropriate figures from programmatic data • Modify costs as they emerge

20. ACKNOWLEDGEMENTS Funders: Bill & Melinda Gates Foundation BRC at Imperial College London The Monument Trust For helpful discussion and data: Prof Charlie Gilks (UNAIDS) Maureen Murtagh (formerly CHAI) Dr Graham Cooke (Imperial)