Viral Breakthrough Episodes Among Persons with HIV in Care in Alberta, Canada: Clinical and Public Health Implications.

Unsuppressed HIV viremia damages immunity and increases the risk for secondary HIV transmission. Successful engagement of persons with HIV (PWH) into care resulting in viral suppression is vital. PWH already engaged in care, who, after achieving viral suppression, experience viral breakthrough episodes (VBEs) with a sequence of suppressed/unsuppressed/suppressed viral loads remain problematic. We examined the frequency and outcomes of PWH experiencing VBE. HIV care is provided at no cost to all patients under Alberta's universal health program. All PWH followed at Southern Alberta Clinic, Canada, with two or more viral load tests between January 1, 2010, and January 1, 2020, were evaluated. Sociodemographic, clinical, and lifestyle variables were determined along with health outcomes (CD4 levels, HIV-related hospitalizations, and HIV/AIDS-related mortality). Descriptive and multi-variable analyses were performed comparing PWH with and without VBEs. Of 2096 PWH, 386 (18%) experienced one or more VBEs. A higher risk of VBEs was seen in adjusted analyses in those diagnosed age ≤40 years. Increased risk of VBE was seen with injection drug use (46%) and in heterosexuals (56%) compared with MSM. Experience of intimate partner violence, unstable housing, homelessness, and past incarceration also increased risks by 36%, 44% 79%, and 51%, respectively. PWH with VBEs experienced lower CD4 counts (median -417/mm3 vs. 576/mm3), higher rates of HIV-related hospitalizations (16% vs. 5%), and a 67% increased risk of death (95% confidence interval 1.17-2.39) over the study period. Nearly 20% of all PWH, after achieving viral suppression, experienced VBEs. Distinct clinical, lifestyle, and life experiences predict PWH at greatest risk for more than one VBEs. Serious negative health outcomes of VBEs were identified, suggesting that novel customized care programming is required for PWH at greatest risk.