Difficult-to-treat asthma patients from ethnic minority groups in central England are at an enhanced risk of house dust mite sensitisation

Adel H Mansur; Julie Marsh; Ali Bahron; Maximillian Thomas; Gareth Walters; John Busby; Liam G Heaney; Mamidipudi Thirumala Krishna

doi:10.1002/clt2.12303

Difficult-to-treat asthma patients from ethnic minority groups in central England are at an enhanced risk of house dust mite sensitisation

Clin Transl Allergy. 2023 Oct;13(10):e12303. doi: 10.1002/clt2.12303.

Authors

Adel H Mansur^{1

2}, Julie Marsh¹, Ali Bahron¹, Maximillian Thomas¹, Gareth Walters¹, John Busby³, Liam G Heaney⁴, Mamidipudi Thirumala Krishna⁵

Affiliations

¹ Birmingham Regional Severe Asthma Service, Birmingham Heartland Hospital, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK.
² Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK.
³ Centre for Public Health, School of Medicine, Dentistry and Biomedical Sciences, Queens University Belfast, Belfast, UK.
⁴ Wellcome-Wolfson Centre for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, UK.
⁵ Institute of Immunology and Immunotherapy, University of Birmingham, and University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK.

Abstract

Background: House dust mite (HDM) is the most common sensitising allergen in asthma. Ethnic minority groups (EMGs) in the UK are more likely to live in deprived conditionings with a greater exposure to HDM and other aero-allergens.

Aim: To compare the ethnicity-based patterns of sensitisation to aero-allergens and the impact of ethnicity on clinical outcomes in patients with difficult-to-treat asthma (DTA).

Methods: Data of patients with DTA were extracted from the registry of the Birmingham Regional Severe Asthma Service (BRSAS), which have a catchment population of 7.3million from Central England. Patients from White and EMG backgrounds were compared in terms of the prevalence of atopy, total serum immunoglobulin E (IgE), specific serum IgE (ssIgE) and asthma related clinical outcomes. Logistic regression analysis was conducted to explore ethnicity-based risk factors for HDM sensitisation.

Results: A total of 1272 patients [White 1016 (79.9%), EMG 256 (20.1%) EMG] with a median age of 51 years (range 16-97) were included in the analysis. Patients from EMG were more likely (64%) to reside in the worst scale of index of multiple deprivation (IMD) than the White patients (25.5%), p < 0.0001. Positive HDM sensitisation was more prevalent in the EMG than in the White group [142/216 (66%) versus 375/842 (45%), p < 0.0001]. The median HDM ssIgE level was higher in the EMG than in the White group [3.0 KUA/L (IQR 0.06, 11.5) versus 0.1 (0.01, 3.0), p < 0.000001]. The odds ratio for positive sensitisation to HDM conveyed by the EMG status was 2.61 (95%CI, 1.8-3.8), p < 0.0001. Compared to the White group, the EMG had higher median total serum IgE [326 KU/L (115, 971) versus 114 (29.8, 434.8), p < 0.000001], higher blood eosinophil count (0.36 × 10⁹ (0.18, 0.62) versus 0.23 (0.1,0.47), p < 0.000001), were marginally more atopic (79.2% vs. 75.6%, p = 0.098) and were less likely to being on maintenance oral corticosteroids (22% vs. 39.7%, p < 0.0001).

Conclusion: In this DTA cohort, positive HDM sensitisation was greater amongst the EMG than the White patients. The EMG status was a significant risk factor for HDM sensitisation.

Keywords: biomarkers; disparities; ethnicity; house dust mite; severe asthma.

Grants and funding

University Hospitals Birmingham NHS Foundation Trust charitable funds