Uncovering Outcome Disparities of β2 Adrenergic Agonists in Blacks: A Systematic Review

Abstract Purpose Outcome differences driven by variation in Blacks' biologic response to treatment may contribute to persistent racial disparities in asthma morbidity and mortality. This review assessed systematic variation in β2 agonist treatment outcomes among Blacks compared to other groups. Methods We conducted a systematic review of studies reporting differential response to β2 agonists among Blacks, including studies identifying pharmacogenetic variants. Results Of 3158 papers, 20 compared safety or efficacy of β2 agonists among Blacks as compared with other subgroups. Six papers evaluating efficacy of short-acting β2 agonists (SABA) found similar or improved results among Blacks compared with other groups, while one small study found reduced response to SABA therapy among Blacks. Reports of safety and efficacy of long-acting β2 agonists (LABA) indicated similar results among Blacks in four papers, while four reports found reduced safety among Blacks, as compared with other groups. Four papers assessed genomic variation and relative treatment response in Blacks, with two finding significant effects of the p.Arg16Gly variant in ADRB2 on β2 agonist response and one finding significant gene-gene IL6/IL6R interaction effects on albuterol response. Conclusions Evidence suggests the potential for differences in β2 agonist outcomes among Blacks compared with other groups. This literature, however, remains small and significantly underpowered for substantive conclusions. There are notable opportunities for adequately-powered investigations exploring safety and efficacy of β2 agonists among Blacks, including pharmacogenomic modifiers of response.