A 68-year-old man with a 40 pack-year smoking history has chronic cough and exertional dyspnoea. Spirometry shows FEV1/FVC 0.55 and FEV1 55% predicted with minimal reversibility. He has daily symptoms and two moderate exacerbations requiring oral steroids in the past year. He currently uses a short-acting bronchodilator as needed. According to the latest Canadian COPD pharmacotherapy guideline, what is the most appropriate next step in management?