A systematic review and meta-analysis of the prevalence and epidemiology of asthma in people over 14 years of age in China.

OBJECTIVE: Asthma is a common chronic respiratory disease that seriously affects the health of adults and children. The risk factors for asthma are constantly changing; thus, it is necessary to study the prevalence of asthma and risk factors in different populations. Currently, there have been no epidemiological studies on the prevalence and risk factors of asthma in people over 14 years in mainland China. Therefore, we performed a meta-analysis of the prevalence and risk factors for asthma in mainland China. METHODS: A literature search was conducted for studies on the epidemiology of asthma in China between 2000 and 2020 using English and Chinese databases. Prevalence and epidemiological information on asthma in people aged >14 years were extracted. Meta-analysis was performed using a random-effects model (If I2>50%) with 95% confidence intervals for forest plots. RESULTS: Nineteen studies (including data from 345,950 samples) met our evaluation criteria. The overall prevalence of asthma in Chinese adults is 2%, without differences between Northern and Southern China. The prevalence increased after 2010 compared with that before 2010. The prevalence of asthma also increased with age, with people aged 55-64 years being the most affected. The prevalence of asthma was independent of sex and residence area. In conclusion, the prevalence of asthma among adolescents (age >14 years) and adult population in China has increased since 2010. CONCLUSION: Further studies are necessary to monitor the prevalence of asthma in mainland China. The elderly population also has a high prevalence of asthma, which should be focused on more in the future.

Classification of non-acute bronchial asthma according to allergy and eosinophil characteristics: a retrospective study.

BACKGROUND: Investigating the endotypes of the different asthma phenotypes would help disease monitoring, prognosis determination, and improving asthma management standardization. This study aimed to classify asthma into four endotypes according to the allergic and eosinophilic characteristics and explore the phenotypes (clinical characteristics, pulmonary functions, and fractional expired nitric oxide (FeNO)) of each endotype. METHODS: This retrospective study included non-acute asthma patients treated at the First Hospital of Shanxi Medical University (05/2016-01/2018). The patients were classified into the eosinophilic allergic, eosinophilic non-allergic, non-eosinophilic allergic, and non-eosinophilic non-allergic asthma endotypes. Serum sIgE, lung function, FeNO, and induced sputum cytology were tested and compared among groups. RESULTS: Of the 171 included patients, 22 had eosinophilic allergic asthma, 17 had eosinophilic non-allergic asthma, 66 had non-eosinophilic allergic asthma, and 66 had non-eosinophilic non-allergic asthma. Lung function measurements (FEV1%, FEF25%, FEF50%, FEF75%, and FEF25-75%) showed that airway dysfunction was worse in eosinophilic non-allergic asthma than in the other three endotypes (all P < 0.001). In allergic asthma patients, eosinophilic asthma had worse airway dysfunction than non-eosinophilic asthma (all P < 0.05). Similar results were found in non-allergic asthma (all P < 0.01). The FeNO levels in eosinophilic allergic asthma were higher than in eosinophilic non-allergic and non-eosinophilic non-allergic asthma (both P = 0.001). CONCLUSIONS: FeNO can objectively reflect eosinophilic airway inflammation in asthma. Endotypic classification of asthma patients regarding the allergic and eosinophilic characteristics is conducive to the effective management of patients with asthma.