Impact of low-level viremia with drug resistance on CD4 cell counts among people living with HIV on antiretroviral treatment in China.

Background: Maintaining plasma HIV RNA suppression below the limit of quantification is the goal of antiretroviral therapy (ART). When viral loads (VL) remain in low-level viremia (LLV), or between 201 and 999 copies/mL, the clinical consequences are still not clear. We investigated the occurrence of LLV with drug resistance and its effect on CD4 cell counts in a large Chinese cohort.

Methods: We analysed data of 6,530 ART-experienced patients (42.1 ± 10.9 years; 37.3% female) from the China's national HIV drug resistance (HIVDR) surveillance database. Participants were followed up for 32.9 (IQR 16.7-50.5) months. LLV was defined as the occurrence of at least one viral load (VL) measurement of 50-200 copies/mL during ART. Outcomes were drug resistance associated mutations (DRAM) and CD4 cell counts levels.

Results: Among 6530 patients, 58.0% patients achieved VL less than 50 copies/mL, 27.8% with VL between 50 and 999 copies/mL (8.6% experienced LLV), and 14.2% had a VL ≥ 1000 copies/mL. Of 1818 patients with VL 50-999 copies/mL, 182 (10.0%) experienced HIVDR, the most common DRAM were M184I/V 28.6%, K103N 19.2%, and V181C/I/V 10.4% (multidrug resistance: 27.5%), and patients with HIVDR had a higher risk of CD4 cell counts < 200 cells/μL (AOR 3.8, 95% CI 2.6-5.5, p < 0.01) comparing with those without HIVDR. Of 925 patients with VL ≥ 1000 copies/mL, 495 (53.5%) acquired HIVDR, the most common DRAM were K103N 43.8%, M184I/V 43.2%, M41L 19.0%, D67N/G 16.4%, V181C/I/V 14.5%, G190A/S 13.9% and K101E 13.7% (multidrug resistance: 75.8%), and patients with HIVDR had a higher risk of CD4 cell counts < 200 cells/μL (AOR 5.8, 95% CI 4.6-7.4, p < 0.01) comparing with those without HIVDR.

Conclusion: Persistent with VL 50-999 copies/mL on ART is associated with emerging DRAM for all drug classes, and patients in this setting were at increased risk of CD4 cell counts < 200 cells/μL, which suggest resistance monitoring and ART optimization be earlier considered.