Impact of Mild Anaemia on Dyspnoea during Exertion and Exercise Tolerance in Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Introduction: Dyspnoea and decreased exercise tolerance are symptoms of acute exacerbation of chronic obstructive pulmonary disease (AECOPD). Anaemia is a risk factor for reduced functional capacity and dyspnoea in stable COPD. There is limited information about the impact of anaemia on functional capacity and dyspnoea of patients during AECOPD. The aim of this study was to evaluate the impact of decreased blood haemoglobin concentration on the results of six-minute walking test (6MWT) in patients during AECOPD. Material and methods: A post hoc analysis of data collected from prospective long-term studies on AECOPD. Haemoglobin concentration from the first obtainable hospital measurement were included in the assessment. 6MWT was performed after clinical improvement of the patient. Dyspnoea at baseline and after exercise and oxygen saturation (SpO₂) during exercise was measured. Results: (presented as means ± SD): 402 patients with exacerbation of COPD (COPD stage 3.5 ± 0.6) were examined. Patients with anaemia (26% of those studied, age 74.5 ± 8.2 years) achieved 258.1 ± 125.1 m during 6MWT, with exertional desaturation of 2.9 ± 2.6%. Patients without anaemia (74% of those studied, age 70.2 ± 8.7 years) achieved 271 ± 136.0 m during 6MWT with exertional desaturation of 3.8 ± 3.7%. The haemoglobin concentration did not correlate with 6MWT, dyspnoea during 6MWT, or exercise oxygenation and blood desaturation during exercise. Conclusion: Mildly decreased blood haemoglobin concentration did not influence the results of 6MWT in patients with AECOPD.