Chronic obstructive pulmonary disease (COPD) is a chronic lung disease. Azithromycin, an antibiotic, may be beneficial at reducing the symptoms and severity of the disease. This study will analyze previously collected study data to evaluate the anti-inflammatory properties of azithromycin and determine how azithromycin affects the frequency and severity of COPD exacerbations.

COPD is a disease in which the lung airways are partly damaged and obstructed, making it difficult to breathe. The most common cause is cigarette smoking, but breathing in other types of lung irritants, including pollution, dust, and chemicals, over a long period of time may also contribute to COPD. It is the fourth leading cause of death in the United States. Symptoms include coughing, excess mucus production, shortness of breath, wheezing, and chest tightness.

Some bacterial infections may worsen COPD exacerbations. Current studies are examining if the macrolide antibiotic azithromycin may be beneficial at reducing the frequency and/or severity of COPD exacerbations. Azithromycin also has anti-inflammatory properties that may reduce the severity of COPD exacerbations by inhibiting the matrix metalloprotease (MMP)-catalyzed breakdown of collagen and the subsequent generation of proline-glycine-proline (PGP), a substance produced in response to collagen breakdown. An increase in PGP levels may indicate an increase in inflammation, which can worsen COPD symptoms. NHLBI's COPD Network Macrolide study includes people with COPD who were randomly assigned to receive either azithromycin or placebo for 1 year. For this current study, researchers will examine the Macrolide participants' previously collected blood samples, sputum samples, and study data, including information on COPD exacerbations and azithromycin effects. The purpose of this study is to examine the anti-inflammatory properties of azithromycin in people with COPD.

Inclusion Criteria:

• Participating in the COPD Network Macrolide study
• Clinical diagnosis of at least moderate COPD
• Cigarette consumption of 10 pack years or more

Exclusion Criteria:

• Diagnosis of asthma
• Predicted life expectancy of less than 3 years
• History of hypersensitivity to macrolide antibiotics
• Long-term kidney insufficiency
• Long-term liver insufficiency
• Prolonged QT interval
• Use of medications that may prolong the QT interval

Community

The number of participants included in this study is small as sputum samples were available only from a minority of participants in the parent trial. Therefore, this greatly reduced the overall number of participants analyzed.

From baseline to 12 months.

This research was carried out as an ancillary study to the Macrolide trial of the NHLBI COPD Clinical Research Network (CRN). This was a prospective, parallel group, placebo-controlled, double-blind study of the efficacy of azithromycin in the chronic, outpatient management of COPD.

We were limited by the number of participants included in this study is small, as sputum samples were available only from a minority of participants in the parent trial.