title: The impact of acid-suppressing drugs to the patients with chronic obstructive pulmonary disease: A nationwide, population-based, cohort study.
abstract: BACKGROUND
  A high prevalence of gastroesophageal reflux disease symptoms has observed among chronic obstructive pulmonary disease (COPD) patients, and proton-pump inhibitors (PPIs) are the main medication in clinical practices. The aim of this study is to analyze the impact of PPIs to the risk of pneumonia in the cases with COPD.
  
  
  METHODS
  This was a nationwide, population-based, cohort study using National Health Insurance Program in Taiwan. The enrolled cases were newly-diagnosed COPD, older than 30 years, between 2001 and 2005. Patients' prescriptions with PPIs and histamine receptor 2 antagonists (HR2As), >2 months, were identified. The appearance of pneumonia and mortality of these enrolled patients was recorded. Multivariate Cox's regression was used to examine the influence of acid-suppressing drugs to pneumonia on individuals with COPD.
  
  
  RESULTS
  A total of 17,498 patients were included, of whom 109 (0.6%) and 526 (3%) cases had used PPIs and HR2As respectively. The risk of pneumonia existed when patients had used concurrent PPIs (adjusted hazard ratio [HR] = 1.76; 95% confidence interval [CI] = 1.33-2.34) or HR2As (adjusted HR = 1.25; 95% CI = 1.07-1.47). The positive association was lost in the cases over 70 years. The ratio of mortality also increased in those with PPIs or HR2As.
  
  
  CONCLUSIONS
  Acid-suppressing drugs, especially PPIs, are attributed to more pneumonia happening in COPD patients compare with nonusers. The association was lost in elderly cases. Use acid-suppressing drugs should be careful about a higher possibility of pneumonia in younger individuals with COPD.
authors.affiliation: Department of Internal Medicine, Division of Gastroenterology and Hepatology, Taichung Veterans General Hospital, Taichung ; Department of Internal Medicine, Chung Shan Medical University, Taichung, Taiwan.
authors.forename: Shou-Wu
authors.initials: SW
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Division of Gastroenterology and Hepatology, Taichung Veterans General Hospital, Taichung ; Department of Internal Medicine, Yang-Ming University School of Medicine, Taipei, Taiwan.
authors.forename: Han-Chung
authors.initials: HC
authors.lastname: Lien
authors.affiliation: Department of Internal Medicine, Division of Gastroenterology and Hepatology, Taichung Veterans General Hospital, Taichung ; Department of Internal Medicine, Chung Shan Medical University, Taichung, Taiwan.
authors.forename: Chi-Sen
authors.initials: CS
authors.lastname: Chang
authors.affiliation: Department of Internal Medicine, Division of Gastroenterology and Hepatology, Taichung Veterans General Hospital, Taichung ; Department of Internal Medicine, Yang-Ming University School of Medicine, Taipei, Taiwan.
authors.forename: Hong-Zen
authors.initials: HZ
authors.lastname: Yeh
authors.affiliation: Department of Internal Medicine, Division of Gastroenterology and Hepatology, Taichung Veterans General Hospital, Taichung ; Department of Internal Medicine, Yang-Ming University School of Medicine, Taipei, Taiwan.
authors.forename: Teng-Yu
authors.initials: TY
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Division of Gastroenterology and Hepatology, Taichung Veterans General Hospital, Taichung.
authors.forename: Chun-Fang
authors.initials: CF
authors.lastname: Tung
keywords: Chronic obstructive pulmonary disease; histamine receptor 2 antagonists; pneumonia; proton-pump inhibitors