BACKGROUND: Adding a long-acting beta(2)-agonist (LABA) to inhaled corticosteroids (ICS) using a fixed-dose combination (FDC) inhaler is the UK guideline recommendation for children aged more than 4 years with uncontrolled asthma. The evidence of benefit of adding an FDC inhaler over a separate LABA inhaler is limited. OBJECTIVE: The objective of this study was to compare the effectiveness of a LABA added as an FDC inhaler, and as a separate inhaler, in children with uncontrolled asthma. METHODS: Two UK primary care databases were used to create a matched cohort study with a 2-year follow-up period. We included children prescribed their first step-up from ICS monotherapy. Two cohorts were formed for children receiving an add-on LABA as an FDC inhaler, or a separate LABA inhaler. Matching variables and confounders were identified by comparing characteristics during a baseline year of follow-up. Outcomes were examined during the subsequent year. The primary outcome was an adjusted odds ratio for overall asthma control (defined as follows: no asthma-related hospital admission or emergency room visit, prescription for oral corticosteroids or antibiotic with evidence of respiratory consultation, and <= 2 puffs of short-acting bagonist daily). RESULTS: The final study consisted of 1330 children in each cohort (mean age 9 years; 59% male). In the separate ICSDLABA cohort, the odds of achieving overall asthma control were lower (adjusted odds ratio, 0.77 [95% confidence interval, 0.66-0.91]; P =.001) compared with the FDC cohort. CONCLUSION: The study demonstrates a small but significant benefit in achieving asthma control from an add-on LABA as an FDC, compared with a separate inhaler and this supports current guideline recommendations. (C) 2016 American Academy of Allergy, Asthma & Immunology