Nutritional anemia is associated with increased risk of severe COPD exacerbations: a prospective cohort study.

BACKGROUND

Anemia prevalence in chronic obstructive pulmonary disease (COPD) varies widely across studies, and data on anemia subtypes and their association with mortality or COPD exacerbation readmission are limited.

OBJECTIVES

We aimed to investigate anemia subtypes and their association with mortality and readmission for acute exacerbation of COPD (AECOPD) in patients hospitalized for AECOPD.

METHODS

In this prospective observational cohort study, patients with COPD aged ≥45 y hospitalized for severe exacerbations in a Belgian nationwide database were included. Cox regression models investigated associations between anemia (or its subtypes) and (postdischarge) mortality and AECOPD readmission, adjusted for age, sex, socioeconomic status, smoking, weight, and age-adjusted Charlson Comorbidity Index. Inverse probability of treatment weighting examined the association between anemia treatment and mortality across anemia subtypes.

RESULTS

Among 32,152 patients with COPD discharged from the hospital, 5956 (18.5%) had anemia. Nutritional anemia was most frequent (49.3%), followed by anemia of chronic disease (ACD; 31.3%). Anemia was associated with a 30% higher postdischarge mortality risk [adjusted hazard ratio (aHR): 1.30, 95% confidence interval (CI): 1.23, 1.37], and 8% higher readmission risk (aHR:1.08, 95% CI: 1.03, 1.14). Patients with hematologic anemia had the highest postdischarge mortality risk (aHR: 1.75, 95% CI: 1.54, 1.99), followed by nutritional anemia (aHR: 1.29, 95% CI: 1.20, 1.39). Only nutritional anemia was associated with increased readmission risk (aHR: 1.18, 95% CI: 1.10, 1.25). Treatment effects differed by anemia subtype, with iron, vitamin B12, and erythroid-stimulating agent (ESA) associated with lower postdischarge mortality in nutritional anemia; folic acid and iron in hematologic anemia; and ESA and iron in ACD.

CONCLUSIONS

Nutritional anemia is the predominant subtype in hospitalized patients with AECOPD, and its increased readmission risk calls closer attention to iron deficiency in patients with COPD. All subtypes of anemia are associated with higher postdischarge mortality risk, but targeted treatment may reduce mortality risk and represents a potential strategy to improve outcomes.