Six-monthly CD4 cell monitoring 'unnecessary' for people doing well on HIV therapy

CD4 cell count monitoring more than once a year is unnecessary for people doing well on HIV therapy, investigators from the United States report in the online edition of Clinical Infectious Diseases. They found that there was a 99% probability over five years that people whose viral load was suppressed and who had a CD4 cell count above 300 cells/mm³ would maintain a CD4 level adequate to protect them from opportunistic infections.

“Our data supports less frequent CD4 monitoring in clinically stable, virally suppressed patients and suggests that routine CD4 monitoring for this population may be unnecessary,” write the authors.

They believe that reducing the frequency of CD4 cell testing would have benefits for both providers and patients, saving substantial sums of money and reducing anxiety in people with HIV.

The author of an editorial accompanying the study labelled the current frequency of CD4 cell monitoring in people undergoing successful HIV therapy a “wasteful addiction”.

CD4 cell counts are used to gauge the health of the immune system and have long been a central component of HIV care. Regular monitoring is important for people who are not taking antiretroviral therapy, and a fall in CD4 cell count to around 350 cells/mm³ is the threshold for starting antiretroviral therapy in the United Kingdom. (Other countries have begun to recommend earlier treatment, although expert opinion in the United States remains divided on when to start treatment in the absence of data from a large randomised study.)

Current United States treatment guidelines recommend that people who are doing well on HIV treatment with an undetectable viral load should have their CD4 cell count monitored every six to twelve months.

Investigators from the Department of Veterans Affairs in Washington DC wanted to see if this frequency of monitoring was clinically justified. They especially wanted to establish the risk of the CD4 cell count falling to below 200 cells/mm³ – indicating vulnerability to HIV-related opportunistic infections and the need for prophylaxis – for people treated with anti-HIV drugs whose viral load was suppressed to below 200 copies/ml.

A total of 832 treated people who received care between 1998 and 2011 were included in the study. All had paired CD4 cell and viral load results. The median period of follow-up was 7.7 years and the median interval between CD4 and viral load monitoring was 113 days.

Overall, 93% of participants maintained their CD4 cell count above the 200 cell/mm³ threshold during periods of virological suppression. In 61 participants CD4 cell count dipped below this level. However, in 24 individuals the cause was unrelated to HIV.

The investigators calculated that people with CD4 cell counts between 300 and 349 cells/mm³ and virologic suppression had a 95% probability over four years of maintaining a CD4 cell count above the 200 cell/mm³ level. When baseline CD4 cell count was above 350 cells/mm³, the probability was 97% and increased to 99% when non-HIV-related causes of CD4 cell count decline were excluded.

The investigators believe their results show that frequent, routine monitoring of CD4 cell count in people undergoing successful HIV treatment is unnecessary, even harmful.

“Reduced CD4 monitoring would provide a substantial cost saving,” they write. “For example, 55% of our patients had both viral suppression < 200 and CD4 > 300...if these patients were monitored only annually, over $41,000 would be saved.” Another benefit would be “alleviating patient anxiety from fluctuations in serial CD4 due to laboratory and physiologic variability”.

The author of an accompanying editorial believes that frequent monitoring of CD4 cell count in stable, treated patients with virologic suppression is unnecessary, with no impact on “clinical decision making”.

He suggests that care guidelines should be revised, removing the recommendation for regular CD4 cell count tests in clinically stable patients. Instead, guidelines should stress the primacy of viral load monitoring for individuals treated with antiretroviral drugs.

“We would need to continue educating our patients about why we are changing our practice,” writes the author. “The message should be simple – we no longer need this test to make decisions about your treatment.”

Note: these findings should be discussed with a medical professional familiar with your medical history before making individual decisions about the frequency of clinic visits.