Does Discordance Between CD4-Cell Count and CD4 Percentage Matter?

In HIV-infected patients, CD4-cell count and percentage (%) both predict clinical disease progression. However, the two measures are occasionally discordant. Which patients are most likely to have discrepant results, and what are the clinical implications of discordance? Investigators recently addressed these questions, using data from a prospective cohort study in the U.K.

A total of 22,476 untreated patients were grouped into three categories based on CD4 measurements: low discordance (CD4% ≤10th percentile for a particular CD4 cell–count range), concordance (CD4% within the central 80% for a particular CD4 cell–count range), or high discordance (CD4% ≥90th percentile for a particular CD4 cell–count range). The median CD4 count was 384 cel…