Is the rate of virological failure to cART continuing to decline in recent calendar years?

•Notwithstanding modern HAART therapies HIV + subjects continue to fail.•In the ICONA cohort the rate of VF increased with higher numbers of previous VFs.•The rate of VF had been lower in recent years, e.g. 2014–2017 vs 2006–2009.•Several factors were associated to a lower risk of VF.•These are Italian origin, longer virological suppression, and university education. Despite the high rate of virological success of combined antiretroviral therapy (cART), HIV infected individuals continue to fail. In this contest, it is unclear whether having previously experienced virological failure (VF) of cART remains an important predictor of future risk of VF in people receiving cART in modern times. We investigated the rate of VF and factors potentially associated with this event in 9220 HIV-1 infected patients enrolled in the Icona Cohort who showed a stable viral suppression on modern cART regimens after January 1, 2006. We investigated two main exposure factors: current calendar period (2006–2009; 2010–2013; 2014–2017) and number of VFs (0; 1–3; >3) prior to baseline. Relative rates of VF were estimated from fitting a Poisson regression model. Seven-hundred-seventy-nine patients experienced VF over follow-up for an overall rate of 2.08 per 100 person years of follow-up (PYFU, 95%CI: 1.93–2.22). The rate of VF increased with higher numbers of previous VFs: patients with >3 previous VFs had a rate of 4.87 (4.10–5.78), 2.75-fold higher than that observed in patients without any previous VF (p