A 62-year-old male with a 40 pack-year smoking history undergoes pulmonary function testing for worsening chronic shortness of breath. Results show an FEV1 of 48% predicted, FVC of 82% predicted, FEV1/FVC ratio of 0.58, and a Total Lung Capacity (TLC) of 122% predicted. After inhalation of 400 mcg of albuterol, the FEV1 increases by 4% and 70 mL. What is the most accurate diagnosis?