Effect of tiotropium on lung function decline in early-stage of chronic obstructive pulmonary disease patients: propensity score-matched analysis of real-world data

Abstract

Background

Tiotropium failed to slow the annual rate of forced expiratory volume in 1 second (FEV ₁) decline in chronic obstructive pulmonary disease (COPD) patients with <70% predicted FEV ₁. However, the rate of FEV ₁ decline is known to be faster at early stages, which suggests that the effects of tiotropium may be more prominent in early-stage of COPD patients. The aim of this study was to test the hypothesis that tiotropium modifies the rate of FEV ₁ decline in COPD patients with an FEV ₁≥70%.

Methods

We retrospectively reviewed the records of COPD patients diagnosed between January 1, 2004, and July 31, 2012, at Seoul National University Hospital, Seoul National University Bundang Hospital, and Seoul Metropolitan Government-Seoul National University Boramae Medical Center. The inclusion criteria were as follows: age ≥40 years, postbron-chodilator (BD) FEV ₁≥70% of predicted and FEV ₁/FVC (forced vital capacity) <0.70, and spirometry more than two times at certain times of the year. Conversely, the exclusion criteria were as follows: asthma, lung cancer, pulmonary tuberculosis, pulmonary resection, or long-term use of a short-acting muscarinic antagonist. The annual lung function decline in patients using tiotropium was compared with that in patients not using the drug.

Results

Of the 587 patients enrolled in the study, 257 took tiotropium. Following propensity score matching, 404 patients were included in the analysis. The mean annual rate of post-BD FEV ₁ decline was 23.9 (tiotropium) and 22.5 (control) mL/yr ( P=0.86); corresponding pre-BD values were 30.4 and 21.9 mL/yr ( P=0.31), respectively. Mean annual rate of post-BD FVC decline was 55.1 (tiotropium) and 43.5 (control) mL/yr ( P=0.33); corresponding pre-BD values were 37.1 and 33.3 mL/yr ( P=0.13).

Conclusion

Therefore, tiotropium does not reduce the rate of lung function decline in COPD patients with FEV ₁≥70%.