Impact of sex on severe asthma: a cross-sectional retrospective analysis of UK primary and specialist care.

INTRODUCTION: After puberty, females are more likely to develop asthma and in a more severe form than males. The associations between asthma and sex are complex with multiple intrinsic and external factors. AIM: To evaluate the sex differences in the characteristics and treatment of patients with severe asthma (SA) in a real-world setting. METHODS: Demographic, clinical and treatment characteristics for patients with SA in the UK Severe Asthma Registry (UKSAR) and Optimum Patient Care Research Database (OPCRD) were retrospectively analysed by sex using univariable and multivariable logistic regression analyses adjusted for year, age and hospital/practice. RESULTS: 3679 (60.9% female) patients from UKSAR and 18 369 patients (67.9% female) from OPCRD with SA were included. Females were more likely to be symptomatic with increased Asthma Control Questionnaire-6 (UKSAR adjusted OR (aOR) 1.14, 95% CI 1.09 to 1.18) and Royal College of Physicians-3 Question scores (OPCRD aOR 1.29, 95% CI 1.13 to 1.47). However, they had a higher forced expiratory volume in 1 second per cent (FEV1%) predicted (UKSAR 68.7% vs 64.8%, p<0.001) with no significant difference in peak expiratory flow. Type 2 biomarkers IgE (UKSAR 129 IU/mL vs 208 IU/mL, p<0.001) and FeNO (UKSAR 36ppb vs 46ppb, p<0.001) were lower in females with no significant difference in blood eosinophils or biological therapy. Females were less likely to be on maintenance oral corticosteroids (UKSAR aOR 0.86, 95% CI 0.75 to 0.99) but more likely to be obese (UKSAR aOR 1.67, 95% CI 145 to 1.93; OPCRD SA aOR 1.46, 95% CI 1.34 to 1.58). CONCLUSIONS: Females had increased symptoms and were more likely to be obese despite higher FEV1% predicted and lower type 2 biomarkers with consistent and clinically important differences across both datasets.

Biologic therapy practices in severe asthma; outcomes from the UK Severe Asthma Registry and survey of specialist opinion.

BACKGROUND: several biological treatments have become available for management of severe asthma. There is a significant overlap in the indication of these treatments with lack of consensus on the first-line biologic choice and switching practice in event of treatment failure. AIMS: to evaluate outcomes of biologic treatments through analysis of the UK Severe Asthma Registry (UKSAR), and survey of the UK severe asthma specialists' opinion. METHODS: patients registered in the UKSAR database and treated with biologics for severe asthma in the period between January 2014 and August 2021, were studied to explore biologic treatments practice. This was complemented by survey of opinion of severe asthma specialists. RESULTS: a total of 2,490 patients from 10 severe asthma centres were included in the study (mean age 51.3 years, 61.1% female, mean BMI 30.9kg/m2 ). Biologics use included mepolizumab 1,115 (44.8%), benralizumab 925 (37.1%), omalizumab 432 (17.3%), dupilumab 13 (0.5%), and reslizumab 5 (0.2%). Patients on omalizumab were younger and had earlier age of onset asthma than those prescribed mepolizumab or benralizumab. Patients prescribed mepolizumab and benralizumab had similar clinical characteristics. Those on benralizumab were more likely to continue treatment at approximately one year follow up (93.9%), than those on mepolizumab (80%), or omalizumab (69.6%). The first choice biologic differed between centres and changed over the study time period. Experts' opinion also diverged in terms of biologic initiation choice and switching practice. CONCLUSION: We observed significant variation and divergence in the prescribing practices of biologics in severe asthma that necessitates further research and standardisation.

Clinical and economic burden of severe asthma with low blood eosinophil counts.

BACKGROUND: Type 2 (T2) low severe asthma phenotype is often a result of corticosteroid-overtreated T2-disease due to persistent symptoms, often not related to asthma, and unlikely to respond to high-dose corticosteroid treatment. OBJECTIVE: This study aimed to characterise severe asthma patients with low eosinophil counts (<300 cells/µl) and describe their disease burden and treatment across healthcare settings in the UK. METHODS: A retrospective cohort study of severe asthma patients using linked Clinical Practice Research Datalink (CPRD) Aurum-Hospital Episode Statistics (HES) and UK Severe Asthma Registry (UKSAR) data indexed patients on latest blood eosinophil count (BEC). Clinical characteristics, treatment patterns, outcomes, and healthcare resource use (HCRU) were described by baseline BEC (≤150 and >150 to <300 cells/µl). RESULTS: Analysis included 701 (CPRD-HES) and 1,546 (UKSAR) patients; with 60.5% and 59.4% having BECs ≤150 cells/µl at baseline, respectively. Across BEC groups, the proportion with uncontrolled asthma (≥2 exacerbations) at follow-up (12-months post-index) was 5.4% in CPRD-HES and 45.2% in UKSAR. Maintenance OCS use remained high across BEC groups (CPRD-HES: 29.4%; UKSAR: 51.7%), symptom control remained poor (>200 µg SABA or >500 µg terbutaline/day in CPRD-HES: 48.8%; median ACQ-6 score in UKSAR: 2.0 [1.0-3.3]). HCRU were similar across BEC groups. CONCLUSION: Most patients managed in primary care were infrequent exacerbators, whilst UKSAR patients exacerbated frequently. Large proportions of both patient groups had poor symptom control and continued to receive high levels of maintenance OCS, increasing risk of corticosteroid-induced morbidity. These data highlight the need for rigorous assessment of underlying disease pathology to guide appropriate treatment.

An examination of factorial invariance of the Asthma Control Questionnaire among adults with severe asthma.

BACKGROUND: The Asthma Control Questionnaire (ACQ) is used to assess asthma symptom control. The relationship between the questionnaire items and symptom control has not been fully studied in severe asthmatic patients, and its validity for making comparisons between subgroups of patients is unknown. METHODS: Data was obtained from patients in the United Kingdom Severe Asthma Registry whose symptom control was assessed using the five-item ACQ (ACQ5) (n = 2,951). Confirmatory factor analysis determined whether a latent factor for asthma symptom control, as measured by the ACQ5, was consistent with the data. Measurement invariance was examined in relation to ethnicity, sex and age; this included testing for approximate measurement invariance using Bayesian Structural Equation Modelling (BSEM). The fitted models were used to estimate the internal consistency reliability of the ACQ5. Invariance of factor means across subgroups was assessed. RESULTS: A one-factor construct with residual correlations for the ACQ5 was an excellent fit to the data in all subgroups (Root Mean Square Error Approximation 0.03 [90%CI 0.02,0.05], p-close fit 0.93, Comparative Fit Index 1.00, Tucker Lewis Index 1.00}. Expected item responses were consistent for Caucasian and non-Caucasian patients with the same absolute level of symptom control. There was some evidence that females and younger adults reported wakening more frequently during the night than males and older adults respectively with the same absolute level of symptom control (p<0.001). However approximate measurement invariance was tenable and any failure to observe strong measurement invariance had minimal impact when comparing mean levels of asthma symptom control between patients of different sexes or ages. Average levels of asthma symptom control were lower for non-Caucasians (p = 0.001), females (p<0.01)and increased with age (p<0.01). Reliability of the instrument was high (over 88%) in all subgroups studied. CONCLUSION: The ACQ5 is informative in comparing levels of symptom control between severe asthmatic patients of different ethnicities, sexes and ages. It is important that analyses are replicated in other severe asthma registries to determine whether measurement invariance is observed.