Race and ethnicity, not just insurance, is associated with biologics initiation in asthma and related conditions.

Background: There are pre-existing inequities in asthma care.

Objectives: We sought to evaluate effect modification by race of the effect of insurance on biologic therapy use in patients with asthma and related diseases.

Methods: We conducted inverse probability weighted analyses using electronic health records data from 2011 to 2020 from a large health care system in Boston, Mass. We evaluated the odds of not initiating omalizumab or mepolizumab therapy within 1 year of prescription for an approved indication.

Results: We identified 1132 individuals who met study criteria. Twenty-seven percent of these patients had public insurance and 12% belonged to a historically marginalized group (HMG). One-quarter of patients did not initiate the prescribed biologic. Among patients with asthma, individuals belonging to HMG had higher exacerbation rates in the period before initiation compared to non-HMG individuals, regardless of insurance type. Among HMG patients with asthma, those with private insurance were less likely to not initiate therapy compared to those with public insurance (odds ratio [OR]: 0.67, and 95% CI: 0.56-0.79). Among non-HMG with asthma, privately insured and publicly insured individuals had similar rates of not initiating the prescribed biologic (OR: 1.02; 95% CI: 0.95-1.09). Among those publicly insured with asthma, HMGs had higher odds of not initiating therapy compared to non-HMGs (OR: 1.16; 95% CI: 1.03-1.31), but privately insured HMG and non-HMG did not differ significantly (OR: 0.99; 95% CI: 0.91-1.07).

Conclusions: Publicly insured individuals belonging to HMG are less likely to initiate biologics when prescribed despite having more severe asthma, while there are no inequities by insurance in individuals belonging to other groups.