Hemoglobin and mortality in patients with COPD: A nationwide population-based cohort study

Purpose: Previous studies have reported that anemia increased mortality in patients with COPD. However, it is unclear whether anemia is associated with increased COPD mortality in the general population. The purpose of our study is to identify whether anemia is related to long-term mortality in COPD using a large population-based database. Patients and methods: Using the National Health Insurance Service-Health Screening Cohort, we identified COPD patients with available hemoglobin level. We analyzed mortality among patients with COPD from 2003 to 2013 according to hemoglobin level. Results: A total of 7,114 patients with COPD were identified. Mean age was 65.0±9.3 years, and 62.9% were male. Anemia was present in 469 patients (6.6%). The overall mortality rate was 46.5% in anemia and 32.1% in non-anemia groups (p<0.001). The hazard ratio of anemia for mortality was 1.31 (95% CI, 1.11–1.54). Among patients with anemia, the hemoglobin level correlated well with mortality. Conclusion: Anemia was associated with increased long-term mortality of COPD, and even mild anemia was related to a significantly increased risk.