Characterization of adults with asthma per GINA treatment steps

Abstract

Background: Adult asthma has not been characterized per GINA treatment step≤2 in population-based studies. Aim: To characterize adults with asthma per GINA treatment steps≤2. Methods: Within the Obstructive Lung Disease in Northern Sweden Studies, an asthma cohort was identified in clinical examinations of population samples. In 2012-14, a follow-up with structured interviews, spirometry and blood sampling was performed. Among 1006 participants (71% of invited, 32-92y), 830 had current asthma whereof 553 (67%) used no treatment or treatment according to GINA step≤2. Results: Among the n=553 using GINA step≤2 treatment, 46% used no treatment, 24% used SABA or LABA (w/o ICS), 20% used ICS (w/o LABA) periodically and 9% used low dose ICS (w/o LABA) most days. Allergic sensitization was present in 31% of those without treatment and in 49% of those using low dose ICS most days, with corresponding figures for blood eosinophilia (>300/mL) of 19% and 35%. Respiratory symptoms were common in all treatment steps, also among those without treatment, but most common among those using low dose ICS most days. In contrast, the mean FEV1% of predicted did not change from inclusion to follow-up among those with low dose ICS most days, while it decreased in the other treatment categories. Conclusions: The majority of adults with asthma use asthma treatment according to GINA steps≤2. Allergic features and respiratory symptoms were especially common among those using low dose ICS most days, indicating a more active asthma, while FEV1% of predicted decreased from inclusion to follow-up among all except for those using low dose ICS most days. These results indicate under-treatment of adult asthma.