Benefits
of Adding Viral Load or CD4 Cell Count Monitoring to Clinical Monitoring Alone
Are Modest
In
lower-income developing nations, the World Health Organization (WHO) recommends
a population-based approach to antiretroviral
treatment with standardized regimens and clinical decision making based on
clinical status and -- where available -- CD4 cell count, rather than HIV viral
load monitoring.
The
objective of the present study, published in the April 26, 2008 issue of The
Lancet, was to examine the potential consequences of such monitoring strategies,
especially in terms of survival and emergence of drug resistance.
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 monitoring strategies -- based on viral
load, CD4 cell count, or clinical observation alone -- for determining when to
switch therapy in people who started antiretroviral treatment using the WHO-recommended
first-line regimen of stavudine (d4T;
Zerit), lamivudine (3TC; Epivir),
and nevirapine (Viramune).
Results
•
Over 5 years,
the predicted proportion of potential life-years survived was:
•
83% with viral
load monitoring (switching when HIV RNA > 500 copies/mL);
•
82% with CD4
count monitoring (switching at 50% drop from peak);
•
82% with clinical
monitoring (switching when 2 new WHO stage 3 events or 1 WHO stage 4 event occurs).
•
Corresponding
values over 20 years were 67%, 64%, and 64%.
•
Findings were
robust to variations in model specifications in extensive univariate and multivariate
sensitivity analyses.
•
Although survival
was slightly longer with viral load monitoring, this strategy was not the most
cost effective.
Conclusion
Based
on these findings, the study authors concluded that 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," they noted, "but
widening access to antiretrovirals -- with or without laboratory monitoring --
is currently the highest priority."
HIV
Epidemiology and Biostatistics Group, Department of Primary Care and Population
Sciences, and Royal Free Centre for HIV Medicine, Royal Free and University College
Medical School, University College London, London, UK.
5/16/08
Reference AN
Phillips, D Pillay, AH Miners, and others. 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. The Lancet
371(9622):1443-51. April 26, 2008.
Results
D Bishai, A Colchero and DT Durack. 
