Chronic obstructive pulmonary disease (COPD) is a heterogeneous disorder characterized by usually progressive development of airflow obstruction that is not fully reversible. While most patients will experience symptoms throughout the day or in the morning upon awakening, many patients do not experience their symptoms as constant but report variability in symptoms during the course of the day or over time. Symptom variability adversely affects patients' health status and increases the risk of COPD exacerbations.

We examined data from the literature on symptom variability and control in patients with COPD, with focus on the use of inhaled bronchodilator therapy with long-acting muscarinic antagonist agents (LAMA) plus long-acting β₂-agonists (LABA); in particular twice-daily fixed-dose combination LAMA/LABA therapy with aclidinium/formoterol.

Correct diagnosis and assessment of COPD requires comprehensive clinical and functional evaluation and consideration of individual needs to support the clinical decisions necessary for effective long-term management. Combining bronchodilators from different and complementary pharmacological classes with distinct mechanisms of action can increase the magnitude of bronchodilation as opposed to increasing the dose of a single bronchodilator.

The use of inhaled bronchodilator therapy with LAMA/LABA fixed-dose combinations in patients with stable COPD is supported by current evidence. This treatment approach provides robust effects on lung function and symptom control and may improve patients' adherence to treatment. Administration of the long-acting bronchodilators aclidinium and formoterol as twice daily fixed-dose aclidinium/formoterol 400/12 μg has the potential to control symptoms throughout the 24 h in patients with stable moderate-to-severe COPD.