P-378. Trends in frequency of HIV viral load and CD4 cell count monitoring among Asian cohort of adults with HIV

Abstract Background Viral load testing is recommended to monitor antiretroviral therapy effectiveness. This study examines changes overtime in the frequency of viral load and CD4 testing, as well as the relationship with AIDS diagnosis and mortality among an Asia-Pacific cohort of people with HIV. Methods We included adults enrolled in the Treat Asia HIV Observational Database between 2003-2018 who were on ART for at least one year. VL and CD4 testing rates were analyzed using Poisson regression models. Association between testing frequency and AIDS diagnosis or survival were evaluated using Fine and Gray competing risk regression. Results The analysis included 8446 patients. VL testing rates remained steady at 1 per person-year (PYS) between 2013-2018. Increased VL testing was associated with more frequent CD4 testing ( > 2 tests in the previous year; IRR=1.57, 95%CI 1.53-1.60), later follow-up years (2008-2012: IRR=1.15, 95%CI 1.12-1.18; 2013-2015: IRR=1.07, 95%CI 1.04-1.10), older age (31-40 years: IRR=1.06, 95%CI 1.03-1.08; 41-50 years: IRR=1.08, 95%CI 1.05-1.11; > 50 years: IRR=1.07, 95%CI 1.03-1.11), higher current VL (401-1000 copies/mL: IRR=1.16, 95%CI 1.09-1.24; > 1000 copies/mL: IRR=1.07, 95%CI 1.04-1.11), initial ART regimen (NRTI+PI: IRR=1.07, 95%CI 1.04-1.10; other combinations: IRR=1.11, 95%CI 1.05-1.17), and higher country income levels (upper-middle: IRR=2.17, 95%CI 2.11-2.23; high: IRR=3.14, 95%CI 3.03-3.26). CD4 testing rates decreased from 2.04 to 1.06/PYS over the same period. Lower CD4 testing frequency was associated with HIV exposure mode (MSM: IRR=0.94, 95%CI 0.92-0.96; IDU: IRR=0.93, 95%CI 0.90-0.97; unknown: IRR=0.90, 95%CI 0.87-0.93), higher current CD4 (201-350 cells/µL: IRR=0.95, 95%CI 0.93-0.97; 351-500 cells/µL: IRR=0.89, 95%CI 0.87-0.91; > 500 cells/µL: IRR=0.85, 95%CI 0.83-0.87) and receiving an NRTI+PI first-line combination (IRR=0.96, 95% CI 0.94-0.98). VL and CD4 testing frequencies were not significantly associated with AIDS diagnosis. However, having > 2 CD4 tests in the previous year was associated with higher mortality risks. Conclusion Recognizing demographic, clinical and socio-economic factors affecting the frequency of CD4 and VL testing is critical to optimizing monitoring strategies and improving outcomes for PWH in the region. Disclosures All Authors: No reported disclosures