Patients with symptomatic minimal airflow limitation had significant improvement in spirometric and plethysmographic parameters following early intervention with a long-acting bronchodilator, reported Heung Bum Lee, MD, Chonbuk National University, Jeonju, South Korea.

Statistically significant improvement at 6 months was observed in forced expiratory volume at one second (FEV₁), forced vital capacity (FVC), and residual volume (p<0.05 to p<0.01). Improvement was evident as early as 4 weeks after initiation of tiotropium treatment, Dr. Lee and colleagues reported.

The rationale for the study came from recognition that chronic obstructive pulmonary disease (COPD) is a progressive condition. Early intervention could help slow or stabilize the disease process, investigators noted.

The study involved 16 patients who had minimal airflow limitation that did not meet COPD diagnostic criteria. At enrollment, the patients had a mean FEV₁/FVC ratio of 0.7–0.8, FEV₁ <80% of predicted, smoking history >10 pack-years, and dyspnea on exertion.

The patients were evaluated by spirometry and body plethysmography 2 weeks prior to starting treatment with tiotropium and again after 4 weeks and 6 months of treatment. Prescribed therapy was 18 μg tiotropium, administered once daily.

Spirometry was performed after administration of 400 μg of salbutamol. The FEV₁/FVC ratio did not change significantly from baseline. However, other parameters improved significantly, beginning as early as 4 weeks.

• Prebronchodilator FEV₁: 1.59, 1.66, and 1.74 L; p<0.01

• Postbronchodilator FEV₁: 1.66, 1.72, and 1.78 L; p<0.01

• Prebronchodilator FVC: 2.10, 2.22, and 2.31 L; p<0.01

• Postbronchodilator FVC: 2.24, 2.40, and 2.41 L; p<0.01

• Residual volume: 2.75, 2.63, and 2.16 L; p<0.05

Additionally, inspiratory capacity increased at 4 weeks and 6 months from baseline, but the improvement did not achieve statistical significance (1.25, 1.32, and 1.41 L; p=0.33).

Dr. Lee and colleagues concluded that “these results strongly support that early pharmacologic intervention can be effective in patients with symptomatic minimal airflow limitation.”