Drop in CD4+ counts below 200 cells/µL after reaching (or starting from) values higher than 350 cells/µL in HIV‐infected patients with virological suppression

Background: The aim of the study was to quantify the risk of a drop in CD4(+) counts below 200 cells/mu L after reaching values >350 cells/mu L on antiretroviral therapy (ART) (or after starting ART with CD4(+) count >350 cells/mu L) in the absence of virological failure. Setting: Ambulatory care services, Italy. Methods: Prospective cohort study of patients enrolled in the ICONA Foundation Study cohort who started ART with >350 CD4(+)/mu L or with <350 CD4(+)/mu L and reached values >350 cells/mu L after virological suppression (VS, defined by 2 consecutive viral loads <= 50 copies/mL). The date of CD4 count >350 was the baseline for the analysis and those with >= 1 viral load and CD4(+) count after baseline were included. The primary end point was the cumulative risk (estimated using the Kaplan-Meier method) of a CD4(+) drop below 200 cells/mu L over follow-up, which was censored at the date of virological failure (confirmed HIV-RNA >50 copies/mL), death, or last visit. Results: Six thousand six hundred sixty-three patients were included. A confirmed CD4(+) drop below 200 cells/mu L was never observed over a median follow-up of 45 (Q1: 21, Q3: 89) months, as long as VS was maintained. Upper limits of the 97.5% confidence interval of rates of confirmed CD4(+) drop below 200 cells/mu L were 0.28 and 0.38/1000 person-years of follow-up for patients with <= 350 and >350 CD4(+) cells/mu L at starting ART. Conclusions: In patients who started ART in Italy with >350 CD4(+) cells/mu L or reached >350 CD4(+) cells/mu L after VS, the risk of a CD4(+) drop below 200 cells/mu L in those maintaining VS was negligible.