Outcomes from monitoring of patients on antiretroviral therapy in resource-limited settings with viral load, CD4 cell count, or clinical observation alone: a computer simulation model

Phillips, Andrew N., Pillay, Deenan, Miners, Alec H., Bennett, Diane E., Gilks, Charles F. and Lundgren, Jens D. (2008) Outcomes from monitoring of patients on antiretroviral therapy in resource-limited settings with viral load, CD4 cell count, or clinical observation alone: a computer simulation model. Lancet, 371 9622: 1443-1451. doi:10.1016/S0140-6736(08)60624-8


Author Phillips, Andrew N.
Pillay, Deenan
Miners, Alec H.
Bennett, Diane E.
Gilks, Charles F.
Lundgren, Jens D.
Title Outcomes from monitoring of patients on antiretroviral therapy in resource-limited settings with viral load, CD4 cell count, or clinical observation alone: a computer simulation model
Journal name Lancet   Check publisher's open access policy
ISSN 0140-6736
1474-547X
Publication date 2008-04
Year available 2008
Sub-type Article (original research)
DOI 10.1016/S0140-6736(08)60624-8
Volume 371
Issue 9622
Start page 1443
End page 1451
Total pages 9
Place of publication London, United Kingdom
Publisher The Lancet Publishing Group
Collection year 2009
Language eng
Formatted abstract
Background: In lower-income countries, WHO recommends a population-based approach to antiretroviral treatment with standardised regimens and clinical decision making based on clinical status and, where available CD4 cell count, rather than viral load. Our aim was to study the potential consequences of such monitoring strategies, especially in terms of survival and resistance development.

Methods: A validated computer simulation model of HIV infection and the effect of antiretroviral therapy was used to compare survival, use of second-line regimens, and development of resistance that result from different strategies-based on viral load, CD4 cell count, or clinical observation alone-for determining when to switch people starting antiretroviral treatment with the WHO-recommended first-line regimen of stavudine, lamivudine, and nevirapine to second-line antiretroviral treatment.

Findings:
Over 5 years, the predicted proportion of potential life-years survived was 83% with viral load monitoring (switch when viral load >500 copies per mL), 82% with CD4 cell count monitoring (switch at 50% drop from peak), and 82% with clinical monitoring (switch when two new WHO stage 3 events or a WHO stage 4 event occur). Corresponding values over 20 years were 67%, 64%, and 64%. Findings were robust to variations in model specification in extensive univariable and multivariable sensitivity analyses. Although survival was slightly longer with viral load monitoring, this strategy was not the most cost effective.

Interpretation: For patients on the first-line regimen of stavudine, lamivudine, and nevirapine the benefits of viral load or CD4 cell count monitoring over clinical monitoring alone are modest. Development of cheap and robust versions of these assays is important, but widening access to antiretrovirals-with or without laboratory monitoring-is currently the highest priority. Funding: None.
Keyword Zidovudine Combination Therapy
Thymidine Analog Mutations
Sub Saharan Africa
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Public Health Publications
 
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