The role of HIV asymptomatic status when starting ART on adherence and treatment outcomes and implications for test and treat: the Swiss HIV Cohort Study

BACKGROUND: Since the advent of universal test and treat policies, a higher share of people living with HIV (PLHIV) initiating ART are asymptomatic with a preserved immune system. We explored the potential impact of asymptomatic status on adherence and clinical outcomes. METHODS: PLHIV registered in the Swiss HIV Cohort Study (SHCS) between 2003 and 2018. Asymptomatic: CDC-stage A within 30 days of starting ART. Non-adherence: any self-reported missed doses. Viral failure: viral load>50 copies/mL on two consecutive measurements after >24 weeks on ART. Using logistic regression models, we measured the variables associated with asymptomatic status and adherence and Cox proportional hazard models to assess the association between symptom status and viral failure. RESULTS: Of 7131 PLHIV, 76% started ART when asymptomatic. In multivariable logistic regression models, asymptomatic PLHIV were more likely to be younger, men having sex with men, more educated, having unprotected sex, have a stable HIV-positive partner, lower viral load, and have started ART in later calendar years. Asymptomatic status was not associated with reported non-adherence during follow-up (OR 1.03, 95% CI: 0.93-1.15) while 1478 PLHIV (22%) experienced viral failure a median of 1.9 years (IQR: 1.1-4.2) after starting ART. Asymptomatic PLHIV were at a decreased risk of viral failure (adjusted hazard ratio 0.87, 95% CI: 0.76-1.00, p=0.05) and less likely to develop resistance (14% versus 27%, p