Association between Helicobacter pylori seropositivity and mild to moderate COPD: clinical implications in an Asian country with a high prevalence of H. pylori

BACKGROUND Helicobacter pylori infection is a major cause of gastric diseases. The clinical implications of H. pylori infection in various diseases outside the gastrointestinal system have also been reported, including in some respiratory disorders. In this study, we investigated the seroprevalence of H. pylori in patients with mild to moderate COPD in an Asian country with a high prevalence of H. pylori infection. Also, we aimed to elucidate the association between the seroprevalence of H. pylori and the decline of lung function in patients with COPD. METHODS Participants who underwent a medical checkup for H. pylori at a referral hospital in Korea were recruited for this study. All participants were tested for H. pylori infection using an immunoassay of the H. pylori-specific immunoglobulin G (IgG) concentration and a rapid urease test at the time of endoscopy with a gastric mucosal specimen. We assessed the decline in lung function using the spirometric data of those who underwent spirometry more than three times. RESULTS In total, 603 participants (201 patients with COPD and 402 controls) were analyzed. The seroprevalence of H. pylori IgG in the patients and controls was 45.8% and 52.2%, respectively (P=0.134). The H. pylori IgG level in patients with COPD was not significantly different from that of the controls (114.8 and 109.6 units/mL, respectively; P=0.549). In addition, there were no significant differences in the annual forced expiratory volume in 1 second or forced vital capacity between the participants with H. pylori seropositivity and seronegativity. CONCLUSION This study showed no relationship between H. pylori infection and COPD in a country with a high burden of H. pylori infection. Furthermore, H. pylori infection did not affect the rate of lung function decline in this study population.