Exploring the association between Socioeconomic status and asthma exacerbations: a real-world prospective cohort study in Chinese adults

Background: Few studies based on the Chinese population have explored the correlation between low socioeconomic status (SES) and asthma control in a real-world setting. Methods: This was a prospective cohort study from the ASAN. Patients recruited from the West China Hospital, Sichuan University were included in the current study. The primary outcome was asthma exacerbations within one year from recruitment. The secondary outcomes were levels of inflammation cytokines in blood and sputum. Results: 330 patients (89.7%) completed the one-year visit. There were 103 patients (28.0%) in low SES group (SESLow) and 265 (72.0%) in middle and high SES group (SESMiddle/High). Compared with SESMiddle/High group, the SESLow group had more asthma related hospital visit in the previous year and also more depressive symptoms, but less co-morbidities with rhinitis, eczema and allergy (tested by SPT). The SESLow group had increased IL-6 and YKL-40 in serum, and sputum neutrophils compared with the SESMiddle/High group. During the one year follow up, SESLow was associated with an increased risk of hospitalizations (aOR=2.41, 95% CI=[1.01, 5.67]) after adjustment for age, gender, BMI, smoking, asthma therapy, asthma control, allergy and lung function, but no differences were found for moderate to severe exacerbations or emergency department visits. Conclusions: In our observational study, we found that Chinese asthma patients with a low SES level had an increased risk for asthma-related hospital visits after adjustment for known clinical and environmental risk factors. Associations with systemic inflammation warrant further studies to explore underlying mechanisms.