A year of treatment with tiotropium significantly improved blood gas parameters in hypoxemic patients with severe chronic obstructive pulmonary disease (COPD), as compared with inhaled corticosteroids plus a long-acting beta-agonist (LABA), reported Maria-Christina L. Machado, MD, Federal University, Sao Paulo, Brazil.

Partial arterial oxygen pressure (PaO₂) increased significantly (p<0.001) from baseline and partial carbon dioxide pressure (PaCO₂) decreased significantly (p<0.01) during treatment with tiotropium versus the standard therapy. Additionally, forced expiratory volume in one second (FEV₁) increased significantly (p<0.001) with the bronchodilator compared with inhaled steroids plus LABA.

“These results confirm that tiotropium usage has a significant impact on lung function variables, including arterial blood gas levels in hypoxemic stable outpatients with COPD under long-term oxygen therapy,” said Dr. Machado.

Despite the proven benefits of tiotropium on lung function in COPD patients, the agent's impact on spirometric and arterial blood gas parameters remained uncertain in hypoxemic and severe COPD, according to Dr. Machado. In an effort to resolve the uncertainty, she and her colleagues evaluated outcomes in 67 consecutive patients with severe COPD and a requirement for long-term oxygen therapy. Each patient successively completed 12 months of treatment with each of two therapies: Treatment 1: inhaled steroids plus LABA; Treatment 2: inhaled corticosteroids + LABA and tiotropium. The primary objective was to compare the relative effects of the two therapeutic strategies on three parameters of lung function: PaO₂, PaCO₂, and FEV₁.

Analysis of baseline characteristics showed that the patients had a mean PaO₂ of 49.9 mm Hg, mean PaCO₂ of 47.9 mm Hg, and mean FEV₁ of 34% of predicted. After 12 months of treatment with inhaled corticosteroids and LABA, mean PaO₂ increased to 53.7 mm Hg and FEV₁ to 35% predicted, and PaCO₂ had decreased to 45.1 mm Hg.

Successively, following 12 months of treatment with inhaled steroids plus LABA and tiotropium, mean PaO₂ was 57.4 mm Hg, PaCO₂ was 43.3 mm Hg, and FEV₁ was 38.1% predicted. All three parameters improved significantly as compared with the standard therapy (p<0.01 to p<0.001; Figure 1).

These results have potential implications for health policy and economics. The public health system of Brazil has provided patients access to inhaled corticosteroids plus LABA for severe asthma since 2002, but severe COPD patients from the Federal University of Sao Paulo started having access to these medicines in 2004. However, patients with severe COPD gained access to corticosteroids plus LABA and tiotropium only in 2007, provided by the public health system from the State Government of Sao Paulo.

After July 2007, the opportunity to report pre- and posttiotropium experiences in a cohort of severe COPD patients who were enrolled in a long-term oxygen therapy (LTOT) program for hypoxemic COPD at the Federal University of Sao Paulo was available. Study results show significant improvement in lung function, including arterial blood gas levels, after tiotropium therapy in these patients.

Additionally, because stable hypoxemic COPD outpatients experienced an improvement in all parameters after use of tiotropium and corticosteroids plus LABA and because severe hypoxemia, hypercapnia, and lung dysfunction are recognized independent markers of worst survival and usually are associated with frequent COPD hospitalization, this study suggests that the three drug combination can also bring clinical and socioeconomic benefits for these patients and health care systems.