HIV screening interval influences CD4+ count at initial diagnosis

SAN DIEGO — Infrequent HIV screening was associated with lower initial counts of CD4+ T cells among diagnosed patients in a recent study.

“Lower CD4 counts at time of HIV diagnosis have been attributed to infrequent testing and delays in care,” Catherine Berjohn, MD, MPH, of the infectious diseases division at Naval Medical Center San Diego, said during a presentation. “We know that lower CD4 counts increase the risk of transmission, likely because of the association with higher viral loads, but also because of an increased risk of opportunistic infections and mortality.”

Catherine Berjohn

Berjohn and colleagues retrospectively examined 1,258 participants enrolled in the U.S. Military HIV Natural History Study who were infected during service from 2000 to 2014. Participants (median age, 27 years) were predominately male; 43% were black, 37% white and 13% Latino. Mean and median CD4 cell counts were recorded at diagnosis. These were compared among various intervals of HIV testing by multivariable regression analysis while controlling for other factors such as calendar year, age, gender, race and viral load.

“The actual window of seroconversion has been difficult to characterize in the general population, with the exception of acute HIV seroconversion cases,” Berjohn said. “U.S. military service members are subject to mandated screening at relevant intervals, however, and for this group of people, we can isolate a window of seroconversion.”

Approximately three-quarters of participants (76.6%) were diagnosed with HIV within 2 years of their most recent negative result, and 40.3% were diagnosed within 1 year of their most recent negative result. The mean initial CD4 count was 466 cells/µL, but this decreased among patients whose last negative result came 1 to 2 years before diagnosis, and further decreased among those whose previous negative test was more than 2 years earlier. As a result, longer intervals were associated with decreasing CD4 counts (P < .001), and this finding remained significant when controlling for calendar year. In addition, participants whose last negative result was more than 2 years before their HIV diagnosis had twice the rate of AIDS compared with those who were tested more frequently (P < .027). Similar associations were observed in nonwhite participants, but no relationships were seen concerning viral load and calendar year.

“Early treatment leads to better outcomes overall, with a decrease in reservoir seeding, increase in CD4 recovery potential, decreased effects of chronic inflammatory state and decreased risk of transmission,” Berjohn said. “There’s no reason why these findings wouldn’t be generalizable to the entire U.S. population; however, it may be a bit prohibitive to implement this kind of screening program. But, for closed systems of health care … it may be an interesting option to examine.” – by Dave Muoio

Reference:

Berjohn C, et al. Abstract 118. Presented at: IDWeek; Oct. 7-11, 2015; San Diego.

Disclosure: The researchers report no relevant financial disclosures.