Predictors for the development of progressive severity in new-onset adult asthma

Background: A proportion of patients with adult-onset asthma have severe disease. Risk factors for an increase in asthma severity are poorly known. Objective: We sought to identify predictors for the development of severe asthma in adults. Methods: A cohort of 200 adults with new-onset asthma was prospectively followed for 2 years. At baseline, patients underwent a comprehensive assessment of clinical, functional, and inflammatory parameters. After 2 years, change in asthma severity was assessed by using the Global Initiative for Asthma score (range, 1-4), which is based on asthma control (Asthma Control Questionnaire), lung function (FEV1), and inhaled corticosteroid requirement. ANOVA and multiple regression equations were used in the analysis. Results: One hundred twenty-eight patients completed 2 years of follow-up. Seventeen (13.3%) patients had an increase in asthma severity, whereas 53 (41.4%) patients had a decrease. A lower postbronchodilator FEV1/forced vital capacity ratio and a higher number of cigarette pack years smoked at baseline were significantly associated with an increase in asthma severity at follow-up. Multiple regression equations showed that only the number of cigarette pack years smoked was independently associated with an increase in asthma severity, with an odds ratio of 1.4 (95% CI, 1.02-1.91) for every 10 pack years smoked. Conclusion: A history of cigarette smoking in patients with new-onset adult asthma predicts an increase in asthma severity during the first 2 years of the disease in a dose-dependent manner.