Factors associated with viral rebound among highly treatment-experienced HIV-positive patients who have achieved viral suppression

Objective More and more highly treatment-experienced patients are achieving viral suppression. However, the durability of suppression remains unclear. Methods Patients from Royal Free Hospital (London, UK) and JW Goethe University Hospital (Frankfurt, Germany) who had failed ≥1 antiretroviral (ARV) regimen in all three main drug classes and ≥3 previous ARV regimens and subsequently achieved viral load 400 copies/mL). Results Two hundred and forty-seven patients contributed 723 person-years and 114 viral rebounds [rate=15.8 per 100 person-years; 95% confidence interval (CI) 12.9–18.7]. More recent calendar years of viral suppression [relative risk (RR)=0.90 per year later; 95% CI 0.81–1.00; P=0.05] and greater number of ARVs in the regimen not previously failed (RR=0.78 per 1 ARV more; 95% CI 0.65–0.95; P=0.01) were associated with lower viral rebound rates. At 0–1, 1–2, 2–3 and >3 years after achieving suppression, the rebound rates were 30.9, 9.2, 4.3 and 3.5 per 100 person-years, respectively. Compared to 0–1 years, the adjusted RRs (95% CIs) after 1–2, 2–3 and >3 years were 0.33 (0.18–0.58), 0.21 (0.09–0.48) and 0.14 (0.06–0.33), respectively (P<0.0001). Conclusions Although rebound rates are high, especially in the first year after viral suppression, this risk reduces substantially if highly treatment-experienced patients can maintain viral suppression.