Overall asthma control: the relationship between current control and future risk.

Background: Asthma guidelines emphasize both maintaining current control and reducing future risk, but the relationship between these 2 targets is not well understood.

Objective: This retrospective analysis of 5 budesonide/formoterol maintenance and reliever therapy (Symbicort SMART Turbuhaler(*)) studies assessed the relationship between asthma control questionnaire (ACQ-5) and Global Initiative for Asthma-defined clinical asthma control and future risk of instability and exacerbations.

Methods: The percentage of patients with Global Initiative for Asthma-defined controlled asthma over time was assessed for budesonide/formoterol maintenance and reliever therapy versus the 3 maintenance therapies; higher dose inhaled corticosteroid (ICS), same dose ICS/long-acting beta(2)-agonist (LABA), and higher dose ICS/LABA plus short-acting beta(2)-agonist. The relationship between baseline ACQ-5 and exacerbations was investigated. A Markov analysis examined the transitional probability of change in control status throughout the studies.

Results: The percentage of patients achieving asthma control increased with time, irrespective of treatment; the percentage Controlled/Partly Controlled at study end was at least similar to budesonide/formoterol maintenance and reliever therapy versus the 3 maintenance therapies: higher dose ICS (56% vs 45%), same dose ICS/LABA (56% vs 53%), and higher dose ICS/LABA (54% vs 54%). Baseline ACQ-5 score correlated positively with exacerbation rates. A Controlled or Partly Controlled week predicted at least Partly Controlled asthma the following week (>or=80% probability). The better the control, the lower the risk of an Uncontrolled week. The probability of an exacerbation was related to current state and was lower with budesonide/formoterol maintenance and reliever therapy.

Conclusions: Current control predicts future risk of instability and exacerbations. Budesonide/formoterol maintenance and reliever therapy reduces exacerbations versus comparators and achieves at least similar control.