Background: Chronic obstructive pulmonary disease (COPD) is a disease that affecting body systems especially the respiratory
system, circulatory system and also hematopoietic system.
Objectives: The primary objective of the present study was to determine the prevalence of anemia and polycythemia in COPD
patients. The secondary objectives was to determine factors associated with anemia and polycythemia.
Materials and Methods: The present study was a retrospective study. All medical records of COPD patients visiting the lung diseases clinic of HRH Princess Maha Chakri Sirindhorn Medical Center between January 1, 2016, and December 31, 2019, were reviewed. Complete blood count, biochemistry laboratory results, lung function test, 6-minute walking distance, frequency of exacerbations and admission were recorded.
Results: One hundred twenty-five patients were enrolled. Patients in GOLD stage 1, 2, 3 and 4 were 41.2%, 47%, 9.8% and 2% respectively. Most of the patients were in group A (50.4%). In our study, the prevalence of anemia in COPD patients was 39.2% and none of the patients had polycythemia. There was no association between GOLD classification or group of COPD and anemia. When analyzed by multiple logistic regression, we found that the higher BMI showed a significantly lower risk of anemia than lower BMI (OR 0.877; 95% CI: 0.795 to 0.967) and the frequency of acute exacerbation correlated with anemic condition statistically significant (OR 1.402, 95% CI: 1.142 to 1.721). Anemia and frequency of exacerbation had  very low level of positive correlation (r=0.282) at the significance level.
Conclusion: Anemia was common comorbidity in COPD patients. Lower body mass index and frequency of exacerbation were significantly related to anemia.

Keywords: Chronic obstructive pulmonary disease; Anemia; Polycythemia; Hemoglobin