1308. The Association Between Refill History and Viral Load Suppression in HIV-infected Patients at a University-Based HIV Clinic in the Midwest

BACKGROUND: Patients with HIV (PWH) with sustained virologic suppression (VS) on antiretroviral therapy (ART) achieve better health outcomes and pose effectively no risk of transmitting HIV to their sexual contacts. Adherence to ART is the main predictor of VS in PWH, yet no adherence benchmark has been identified. The clinical utility of ART pharmacy refill history collection is unknown. We hypothesize that pharmacy refill histories of ART represented as a percentage of days covered (PDC) will correlate with VS in PWH. METHODS: We conducted a single-center, retrospective cohort study of PWH ( ≥19 years) receiving care at a Midwestern HIV clinic between January 1, 2018 and December 31, 2018, with at least 1 HIV RNA reading during the study period. Refill histories were collected for each eligible study patient and a PDC was calculated as the “number of tablets dispensed / number of days within study period” to provide an ART coverage measure. ART regimen, sociodemographic, and clinical characteristics were abstracted from the HIV registry. An HIV RNA ≤ 50 copies/mL and a PDC of ≥80% were used as measures of VS and sufficient adherence, respectively. Pearson’s chi-square tests and binary logistic regression were used to determine the effect of PDC on VS. RESULTS: A total of 1019 patients were included in the study. 705 (69%) patients had a PDC ≥80% and 314 (31%) had a PDC <80%. VS between groups was 96% (PDC ≥80%) vs. 74% (PDC < 80%). A significant association was observed between VS and PDC (P < 0.0001) [HJP1]. Patients with a PDC ≥80% were 9.5 times more likely to attain VS as compared with patients with PDC < 80% (95% CI, 5.89–15.17). After adjusting for ART regimen, sociodemographic, and other clinical characteristics, the likelihood of VS remained higher for patients with a PDC ≥ 80% (aOR: 6.3; 95% CI, 3.7–11.0). Factors found to be negatively associated with VS were single marital status (aOR: 0.49; 95% CI, 0.24–0.95), current or historical opportunistic infection (aOR: 0.51; 95% CI, 0.26–0.99), and usage of a multiclass or dual ART regimen (aOR: 0.40; 95% CI, 0.16–0.98). CONCLUSION: The utilization of PDC as an ART adherence benchmark was significantly associated with VS. PDC is an easy measure to calculate and could be useful in the clinical care of PWH. Future prospective studies are needed to confirm these findings. DISCLOSURES: All authors: No reported disclosures.