UK Study Describes CD4 Cell Count Decline in Untreated Patients with HIV

In order to tell how much antiretroviral therapy reduces HIV disease progression and the decline of immune function, it is useful to know how fast CD4 cell counts fall in untreated individuals as a basis of comparison.

As reported in the August 9, 2007 advance online edition of the Journal of Acquired Immune Deficiency Syndromes, researchers conducted a study to determine the rate of CD4 cell decline among participants in the UK Collaborative HIV Cohort (CHIC) Study who had high CD4 counts at the time of HIV diagnosis and were not receiving antiretroviral therapy.

Results

• Among 13,572 patients in the UK CHIC cohort analyzed since 1996, 3631 (27%) presented with a CD4 count of 500 cells/mm3 or higher.

• Among 4268 antiretroviral-naive individuals with at least 1 CD4 count in the 500 to 650 cells/mm3 range, it took a median time of 2.5 years to fall below 350 cells/mm3 (the level at which treatment is recommended).

• Viral load at baseline was a strong predictor of the time it took for the CD4 count to fall below this level.

• The median time to fall below 350 cells/mm3 ranged from 0.7 years for patients with a viral load of 500,000 copies/mL or more, to 4.7 years for those with fewer than 1000 copies/mL.

Conclusion

The study authors concluded that this study "provides timely background data on antiretroviral-naive patients seen in clinical practice to support design of a trial to compare immediate with deferred antiretroviral therapy in people with high CD4 count."

09/28/07

Reference
UK CHIC Study Steering Committee. HIV diagnosis at CD4 count above 500 cells/mm3 and progression to below 350 cells/mm3 without antiretroviral therapy. JAIDS. August 9,2007 [Epub ahead of print].