Study Finds CD4 Increases Impaired in Older Patients
AIDS August 17, 2001, 15:1575±1586 (Matthew Bidwell Goetz Department of Medicine, VA Greater Los Angeles Healthcare System and UCLA School of Medicine, Los Angeles, CA, USA)
The change in raw CD4 cell count and AUCMB was less in men 55 years of age or older than in younger men; differences were statistically significant at months 3, 9, 15 and 18 for the CD4 cell AUCMB (P , 0.05 for all comparisons). Significant differences were found in the proportion of patients who achieved absolute increases of 50, 100, and over 150 CD4 cells after 3 and 9 months of HAART. On average, after one year of HAART, the CD4 cell count increased by 100 cells for younger patients versus 50 cells for older patients. They compared individuals 55 years of age or older with younger individuals.
These data demonstrate that despite excellent virological responses during the 24 months after the initiation of HAART, the rate of CD4 cell increase and the proportion of individuals with an increase of 50, 100, or 150 cells or more were less in men 55 years of age or older. This difference persisted after controlling for the effect of baseline HIV viral load, HCV seropositivity, and patient ethnicity. For every 10 additional years of age there was a replenishment of 35 fewer CD4 cells per year, as measured by the AUCMB.
Data were retrospectively retrieved from routinely collected, comprehensive electronic medical records covering all individuals receiving care at the Veteran's Administration Greater Los Angeles Medical Center between March 1996 and December 1999.
Age-related decreases of thymic-naive CD4 cell production is a particularly appealing explanation for these results. Others have also found a negative association between age and CD4 cell count recovery for individuals who do and do not sustain a robust virological response to HAART. In particular, our data substantiate earlier reports and more clearly evaluate the magnitude of the age-related decreases in CD4 cell recovery. Ours is an ethnically diverse patient population and our outcome persisted for more than one year. Studies before and since HAART found that increased age is associated with a more rapid loss of CD4 cells after primary infection and faster clinical disease progression.
We did not adjust for the effects of the duration of HIV infection, the use of other antiretroviral therapies before HAART, or other co-morbid conditions. Nonetheless, age-related differences in CD4 cell recov- ery could have implications for considerations regarding the timing of antiretroviral therapy in older HIV- infected individuals. These considerations will become increasingly relevant as the HIV-infected patient population ages as a result of the life prolonging effects of HAART.