Assessing differences in inhaled corticosteroid response by self-reported race-ethnicity and genetic ancestry among asthmatic subjects

Abstract

Background Inhaled corticosteroids (ICS) are the preferred treatment for achieving asthma control. However, little is known regarding the factors contributing to treatment response and whether treatment response differs by population group. Objective To assess behavioral, socio-demographic, and genetic factors related to ICS response among African American and European American individuals with asthma. Methods Study participants were part of the Study of Asthma Phenotypes and Pharmacogenomic Interactions by Race-ethnicity (SAPPHIRE). The analytic sample included individuals with asthma aged 12–56 years, >12% bronchodilator reversibility, and a percent of predicted forced expiratory volume at one second (FEV1) between 40–90%. Participants received 6 weeks of inhaled beclomethasone dipropionate. The primary measure of ICS response was a change in Asthma Control Test (ACT) score; the secondary measure was the change in pre-bronchodilator FEV1. Adherence was measured with electronic monitors. Genetic ancestry was estimated for African American participants using genome-wide genotype data. Results There were 339 study participants; 242 self-identified as African American and 97 as European American. Baseline ACT score, percent of predicted FEV1, degree of bronchodilator response, and ICS adherence were significantly associated with ICS response. A baseline ACT score ≤19 was useful in identifying those who would respond as evidenced by the significant dose-response relationship with ICS adherence. Neither self-reported race-ethnicity among all participants nor proportion of African ancestry among African American participants was associated with ICS responsiveness. Conclusions Our findings suggest that baseline lung function measures and self-reported asthma control predict ICS response, whereas self-reported race-ethnicity and genetic ancestry do not.

<p>Pharmacogenomic Response of Inhaled Corticosteroids for the Treatment of Asthma: Considerations for Therapy</p>

“…In any case, the Study of Asthma Phenotypes and Pharmacogenomic Interactions by Race-ethnicity (SAPPHIRE) documented that the self-declared race ethnicity and genetic ancestry do not predict ICS response, in contrast to the baseline measures of lung function and self-reported asthma control. 87 This finding strongly supports the opinion that ICSs are useful in treating asthma, regardless of racial background. 87 …”

Life Impact and Treatment Preferences of Individuals with Asthma and Chronic Obstructive Pulmonary Disease: Results from Qualitative Interviews and Focus Groups

“…The ACT and CAT used in this study are widely used tools, recommended for measurement of asthma and COPD severity [2, 4]. In our study, the mean ACT score was 16.95, indicating more poorly controlled asthma than in large cohorts from Australia and the USA (with mean ACT scores of 19.2 and 18.6, respectively) [43, 44]. Similarly, the mean CAT score in our study was 24.68, indicating a higher impact of COPD on participants’ lives than in the recent UK Salford Lung Study COPD population (where the mean baseline CAT scores were 22.05 in the usual care group and 20.97 in the fluticasone furoate/vilanterol group) [45].…”

Racial disparities in asthma-related health care use in the National Heart, Lung, and Blood Institute's Severe Asthma Research Program

“…Indeed, in one study of Medicaid-enrolled children in 29 states, the ratio of long-term asthma controller medications to total asthma medications was the primary modifiable risk factor for ED use at the individual level. 38 At the population level, use of asthma-preventive medications (ie, inhaled corticosteroids) [40][41][42] and adherence to asthma prescriptions 43 is also lower in black versus white patients and might be due to more negative beliefs about inhaled corticosteroids and a preference for complementary and alternative medicine approaches. 44 We also did not assess health literacy in the present study, which has been associated with adherence to asthma controller medication, asthma medication delivery (ie, inhaler technique), and measures of asthma control.…”