Prevalence of anaemia associated with chronic obstructive pulmonary disease. Study of associated variables.

BACKGROUND: Anaemia is one of the extrapulmonary manifestations of chronic obstructive pulmonary disease (COPD). Its real prevalence, physiopathology and clinical repercussion are unknown. The objectives of our study were: to determine the prevalence of anaemia in patients with stable COPD not attributable to other causes and to establish the relationship of anaemia with clinical, prognostic and inflammatory markers with an important role in COPD.
METHODS: The study included stable COPD patients with no other known causes of anaemia. The following tests were carried out: respiratory function tests; serum determination of erythropoietin and inflammatory markers: high sensitivity C-reactive protein (hs-CRP), fibrinogen, interleukin 6 (IL-6), interleukin 8 (IL-8) and tumour necrosis factor α (TNF-α). Body mass index (BMI), Charlson and BODE indices, the number of exacerbations in the previous year, dyspnoea and quality of life were also calculated.
RESULTS: One hundred and thirty patients were included. Anaemia prevalence was 6.2%. Mean haemoglobin value in anaemic patients was 11.9±0.95g/dL. Patients with anaemia had a lower BMI (P=.03), higher Charlson index (P=.002), more elevated erythropoietin levels (P=.016), a tendency to present a lower FEV1% value (P=.08) and significantly lower IL-6 values when compared to non-anaemic patients (P=.003).
CONCLUSIONS: In our series, the anaemia associated with COPD was less prevalent than that published in the literature to date, and was related to certain clinical and inflammatory markers.