Predictors of accelerated decline in lung function in adult-onset asthma

Little is known about the prognosis of adults with new-onset asthma. Cross-sectional studies suggest that these patients may exhibit accelerated decline in forced expiratory volume in 1 s (FEV₁). However, risk factors for accelerated decline in lung function have not yet been identified.We aimed to identify these risk factors in a prospective 5-year follow-up study in 200 adults with newly diagnosed asthma. In the current study, clinical, functional and inflammatory parameters were assessed annually for 5 years. Linear mixed-effects models were used to identify predictors.Evaluable lung function sets of 141 patients were available. Median (interquartile range) change in post-bronchodilator FEV₁ was -17.5 (-54.2 to +22.4) mL per year. Accelerated decline in FEV₁ was defined by the lower quartile of decline (>54.2 mL per year). Nasal polyps, number of blood and sputum eosinophils, body mass index, and level of exhaled nitric oxide were univariably associated with decline in lung function. Only the latter two were independently associated. Using cut-off values to identify patients at highest risk showed accelerated decline in FEV₁ in all patients with combined exhaled nitric oxide fraction (F_eNO) ≥57 ppb and body mass index (BMI) ≤23 kg·m^-2We conclude that adults with new-onset asthma with both high levels of exhaled nitric oxide and low BMI are at risk of accelerated decline in lung function.