Lung Function Decline in Adult Asthmatics-A 10-Year Follow-Up Retrospective and Prospective Study

Asthma may have an impact on lung function decline but conflicting results are reported in forced expiratory volume in one second (FEV₁) decline. We aimed to describe the changes in FEV₁ in lifelong non-smoking adult asthmatic outpatients during a 10-year follow-up comparing years 1-5 (1st period) with years 6-10 (2nd period) to assess factors affecting these changes. A total of 100 outpatients performed spirometry every 3 months during a 10-year survey. FEV₁/Ht³ slope values of the 2nd period reduced significantly respect to the 1st period (p < 0.0001). FEV₁ slopes of years 1-5 and 6-10 were inversely associated with FEV₁ at enrolment (p = 0.02, p = 0.01, respectively). Reversibility and variability FEV₁ showed a significant effect on the 1st period slopes (p = 0.01 and p < 0.04, respectively). Frequent exacerbators in the 1st year had steeper FEV₁/Ht³ slopes in the 1st period (p = 0.01). The number of subjects using higher doses of ICS was significantly lower at the 10th years respect to the 5th and the 1st year (p < 0.001, p = 0.003, respectively). This study shows that FEV₁ decline in treated adult asthmatics non-smokers, over 10-year follow-up, is not constant. In particular, it slows down over time, and is influenced by FEV₁ at enrolment, reversibility, variability FEV₁ and exacerbation score in the 1st year.