Predictive test
It is expensive to check whether anti-retroviral drugs are working in an HIV-positive patient, but a new approach could halve the costs.
Doctors monitor the success of anti-HIV drugs using a “CD4 count”. The fewer CD4 cells a patient has, the more HIV has damaged the immune system.
When an HIV positive person starts antiretroviral treatment (ART) against HIV, the number of CD4 cells should increase if the ARTs are working. If the CD4 count is below 200, the person has AIDS, according to the Centre for Disease Control.
But these tests are costly and, in developing countries like South Africa, lab equipment and trained staff are limited. To address this, Wits researcher Prof Ian Sanne and a team of international researchers have suggested a new way to predict which patients are likely to have a low CD4 count.
Those patients who are predicted to have a low CD4 count can then have the test done to confirm it. Their “Prediction-Based Classification” tool correctly predicted 90% of low CD4 counts.
Their study was published the PLoS Medicine Journal in April 2012. The authors emphasise that their tool should not replace CD4 tests, but could improve the monitoring of treatment by making better use of money, staff and equipment.
“Introducing PBC will diminish the burden on poorly resourced laboratories, releasing funding to reach more patients,” Sanne told Scidev.net, a prominent science news website for developing countries.
The tool, a mathematical algorithm, could also reduce the need to repeat tests that give unexpected results. Their research also provides a basis for future studies to look at the economic and health benefits of the tool.
Sanne is the founder and director of the Clinical HIV Research Unit at Wits.
Published in Wits Vuvuzela, 18 May 2012
