Homeostatic Measure of Insulin Resistance Is Associated With Future Asthma Exacerbations: A 1-Year Prospective Cohort Study.

BACKGROUND: Recent evidence suggests that insulin resistance affects asthma outcomes. However, the effect of the homeostatic measure of insulin resistance (HOMA-IR) on airway inflammation and asthma exacerbations (AEs) is poorly understood. OBJECTIVE: To analyze the relationship between HOMA-IR and clinical and inflammatory characteristics in patients with asthma, and the association between HOMA-IR and AEs in the following year. METHODS: A prospective cohort study recruited participants with asthma, who were classified into the HOMA-IRhigh group and HOMA-IRlow group based on the cutoff value of 3.80 for HOMA-IR and were observed within 12 months. We evaluated the clinical and inflammatory features and conducted a 1-year follow-up to study the exacerbations. We used negative binomial regression models to analyze the association between HOMA-IR and AEs. RESULTS: Compared with patients in the HOMA-IRlow group (n = 564), those in the HOMA-IRhigh group (n = 61) had higher levels of body mass index, a higher waist circumference and waist-hip ratio, higher triglycerides, lower cholesterol high-density lipoproteins, more neutrophils in the peripheral blood, and elevated IL-5 levels in the induced sputum. Furthermore, patients in the HOMA-IRhigh group had a significantly increased risk for moderate to severe AEs (adjusted incidence rate ratio [aIRR] = 2.26; 95% CI, 1.38-3.70), severe AEs (aIRR = 2.42; 95% CI, 1.26-4.67), hospitalization (aIRR = 2.54; 95% CI, 1.20-5.38), and emergency visits (aIRR = 3.04; 95% CI, 1.80-8.53). CONCLUSIONS: The homeostatic measure of insulin resistance was associated with asthma-related clinical features and airway inflammation, and was an independent risk factor for future AEs. Therefore, insulin resistance may have important implications for managing asthma as a potential treatable trait.

Interaction effect of chronic cough and ageing on increased risk of exacerbation in patients with asthma: a prospective cohort study in a real-world setting.

Background: Older adults with asthma have the greatest burden and worst outcomes, and there is increasing evidence that chronic cough (CC) is associated with asthma severity and poor prognosis. However, the clinical characteristics of older adult patients with both asthma and CC remain largely unknown. Methods: Participants with stable asthma underwent two cough assessments within 3 months to define the presence of CC. Patients were divided into four groups based on CC and age (cut-off ≥60 years). Multidimensional assessment was performed at baseline, followed by a 12-month follow-up to investigate asthma exacerbations. Logistic regression models were used to explore the interaction effect of CC and age on asthma control and exacerbations. Results: In total, 310 adult patients were prospectively recruited and divided into four groups: older CC group (n=46), older non-CC group (n=20), younger CC group (n=112) and younger non-CC group (n=132). Compared with the younger non-CC group, the older CC group had worse asthma control and quality of life and increased airflow obstruction. The older CC group showed an increase in moderate-to-severe exacerbations during the 12-month follow-up. There was a significant interaction effect of CC and ageing on the increased moderate-to-severe exacerbations (adjusted risk ratio 2.36, 95% CI 1.47-3.30). Conclusion: Older asthma patients with CC have worse clinical outcomes, including worse asthma control and quality of life, increased airway obstruction and more frequent moderate-to-severe exacerbations, which can be partly explained by the interaction between CC and ageing.