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Background: Patients with severe asthma have higher total- and asthma-related health burden than those whose disease is not severe. Recent medical advances in biologic therapies allow better control of asthma characterized by type 2 inflammation. Objective: To study the prevalence of eosinophilic phenotype and IgE levels in Chinese with severe asthma, and the relationship of these type 2 characteristics with asthma control, exacerbations and lung function. Methods: This was a multicenter cross-sectional observational study in Hong Kong, in Chinese adults with asthma on Step 4 or 5 of GINA treatment. Their blood eosinophil counts and total IgE levels were measured, and the relationship of these phenotypic parameters to the number of exacerbations in the past 12 months, and to symptom control in the past 4 weeks, were investigated. Results: A total of 232 subjects were recruited from 6 centers. The mean age was 53.9±12.9 years, with 86 (37.1%) male, and the duration of diagnosed asthma was 26.2±15.7 years. A T-helper 2 (Th2) phenotype indicated by elevated eosinophils and/or IgE was present in 169 (72.8%) of patients. Of 232 patients, 43% had an eosinophilic phenotype (blood eosinophil count ≥300 cell/mm3), while 59% had high total IgE levels of >100 IU/mL (overlap with eosinophilic phenotype in 30%) and 44% had IgE levels of >150 IU/mL (overlap with eosinophilic phenotype in 22%). Subjects with eosinophilic phenotype and IgE >150 IU/mL had a higher rate (1.8 times) of uncontrolled asthma compared with those without such a combination. Conclusion: In Chinese adults with severe asthma defined by the use of conventional maintenance medication regimens, the prevalence of Th2 inflammation is comparable to that reported from other ethnic populations. Those with both eosinophil count ≥300 cell/mm3 and high IgE levels >150 IU/mL had a higher rate of uncontrolled asthma compared with those without a combination of these features.
RESUMEN
BACKGROUND: The real-world relationships between the demographic and clinical characteristics of asthma patients, their prehospitalization management and the frequency of hospitalization due to asthma exacerbation is poorly established. OBJECTIVE: To determine the risk factors of recurrent asthma exacerbations requiring hospitalizations and evaluate the standard of baseline asthma care. METHODS: A territory-wide, multicentre retrospective study in Hong Kong was performed. Medical records of patients aged ≥18 years admitted to 11 acute general hospitals from January 1 to December 31, 2016 for asthma exacerbations were reviewed. RESULTS: There were 2280 patients with 3154 admissions (36.7% male, median age 66.0 [interquartile range: 48.0-81.0] years, 519 had ≥2 admissions). Among them, 1830 (80.3%) had at least one asthma-associated comorbidity, 1060 (46.5%) and 885 (38.9%) of patients had Accident and Emergency Department (AED) attendance and hospitalization in the preceding year, respectively. Patients with advancing age (incidence rate ratio [IRR]: 1.003 for every year increment), a history of AED visits or hospitalization (IRR: 1.018 and 1.070 for every additional episode, respectively) for asthma exacerbation in the preceding year, the presence of neuropsychiatric (IRR: 1.142) and gastrointestinal (IRR: 1.154) comorbidities were risk factors for an increasing number of admissions for asthma exacerbation. For patients with ≥2 admissions, 17.1% were not prescribed inhaled corticosteroid and only 44.6% had spirometry checked before the index admission. Asthma phenotyping was often incomplete, as assessment of atopy (total serum immunoglobulin E level and senitization to aeroallergens) was only performed in 30 (5.8%) patients with ≥2 admissions. CONCLUSIONS AND CLINICAL RELEVANCE: Improving asthma care, especially in elderly patients with a prior history of urgent healthcare utilization and comorbidities, may help reduce healthcare burden. Suboptimal management before the index admission was common in patients hospitalized for asthma exacerbations. Early identification of patients at risk and enhancement of baseline asthma management may help to prevent recurrent asthma exacerbation and subsequent hospitalization.
