Unexpected CD4 decay, hidden adherence gaps, resilience, and the need for long-acting therapy in a single HIV outpatients' cohort.

This single-centre, single-cohort study examines hidden non-adherence to antiretroviral therapy in a setting of persistent optimal viral suppression but concordant absolute and percent CD4 decay by >10% from the previous test. After the finding of important drug holidays in two virologically suppressed patients, between January 2021 and January 2022 all PLWH who fulfilled CD4 decay criteria were asked for how long therapy was interrupted, how many days before re-testing CD4 and HIV RNA was it resumed and the reason for interruption. Of 668 HIV-infected subjects, 61 fulfilled the pre-specified criteria for significant CD4 decay and 15 (2.25% of the total, 25% of the CD4 decay group) admitted long-lasting treatment interruptions, compensated by treatment resumption before the subsequent testing. Eleven treatment interruptions exceeded 28 days, and none was shorter than 15 days. CD4 recovery was worse at 6 months in non-adherent subjects (-0.5 vs + 16/mmc, p < 0.0001) and in non adherence vs immune decay time-related with COVID-19 (0 vs + 22/mmc, p < 0.0001). Reasons for interrupting treatment were travel, psychological, poverty-related, addiction and sentimental sphere problems. Long-acting regimens, with stringent control of precision in timely administration, may protect PLWH from damaging their health status and possibly transmit HIV.