Gaps in guideline adherence: evaluating HLA-B*57:01 screening for abacavir sensitivity and the implementation of evidence-based HIV care.

Objective: Approximately 5-8 % of the population carries the HLA-B*57:01 allele, which increases the risk of severe hypersensitivity reactions to abacavir. Current guidelines and an FDA black box warning recommend HLA-B*57:01 screening for all patients before starting abacavir. We assessed the proportion of patients who undergo screening before initiating abacavir to evaluate adherence to guidelines.

Design: A retrospective cohort study using national IQVIA® PharMetrics Plus reimbursement data.

Methods: Data from the 2014-2022 IQVIA® PharMetrics Plus March 2023 dataset were analyzed. We identified patients aged ≥ 18 years who were newly prescribed abacavir, with ≥ 12 months of continuous enrollment before their first abacavir prescription. We examined the proportion of individuals who received HLA-B*57:01 screening any time before their initial abacavir prescription and conducted a multivariable logistic regression analysis on the receipt of HLA-B*57:01 screening adjusting for sex, age, year, and region.

Results: We identified 7,391 patients newly prescribed abacavir between 2014 and 2022. Approximately 46 % received an HLA-B*57:01 screen before initiation of abacavir. Annual screening rates ranged from 44 % to 50 % between 2015 and 2018 and dropped to 17 % by 2022. Screening was less likely to occur after 2018, compared to earlier in the study period, and more likely for younger as well as male patients.

Conclusions: These findings highlight broader challenges in HIV guideline adherence, emphasizing the need for ongoing evaluation and systematic interventions to improve implementation and patient safety.