ABSTRACT
BACKGROUND: Anaemia is a frequent, clinically relevant condition in various chronic diseases. It seems also to be prevalent in patients with chronic respiratory failure (CRF). We studied the characteristics of anaemia in CRF and its associations with clinical outcome. METHODS: In a prospective design, 271 consecutive patients with CRF were evaluated; patients with other conditions often associated with anaemia were excluded. Haematological laboratory and physiological parameters, health-related quality of life (HRQL), dyspnoea and 48-month survival were determined. Anaemia was defined according to WHO [haemoglobin (Hb)< 13 g/l (male); Hb< 12 g/dl (female)] and using an established algorithm. RESULTS: Among 185 patients included, 18.4% showed anaemia, not depending on chronic obstructive pulmonary disease (COPD) vs. non-COPD (17.6% vs. 19.0%; p = 0.851) or on gender [16.5% (female) vs. 19.8% (male); p = 0.702]. Anaemic patients had higher age, creatinine (p < 0.05 each) and erythropoietin levels (p < 0.001), but lower transferrin saturation (TSAT), serum iron and vitamin B12 levels (p < 0.01 each). By definition, most anaemic patients (67.6%) had disturbances in iron homeostasis according to 'anaemia of chronic disease' and/or true iron deficiency anaemia. Hb was independently related to dyspnoea and HRQL, while TSAT ≥ 20% was linked to less dyspnoea and better subjective exercise capability. Non-survivors had lower Hb and serum iron levels (p < 0.05 each). In multivariate analysis, lower serum iron levels and TSAT were independently associated with mortality (p < 0.05 each). CONCLUSION: Anaemia was common in patients with CRF and often because of disturbed iron homeostasis. Hb and TSAT were linked to functional outcome and HRQL. Lower serum iron levels and TSAT were independent prognostic parameters.
Subject(s)
Respiratory Insufficiency/complications , Aged , Anemia/blood , Anemia/etiology , Anemia/mortality , Chronic Disease , Epidemiologic Methods , Female , Hemoglobins/metabolism , Homeostasis/physiology , Humans , Male , Middle Aged , Respiratory Insufficiency/blood , Respiratory Insufficiency/mortality , Transferrin/metabolismABSTRACT
BACKGROUND: In patients with severe chronic obstructive pulmonary disease (COPD), anaemia is common and associated with impaired long-term survival and quality of life. Whether anaemia is also prevalent in patients with other severe, non-inflammatory respiratory diseases has not yet been systematically tested. METHODS: In 595 patients with obstructive (OD, 54.8%) or restrictive disease (RD, 45.2%) and chronic respiratory failure (CRF), anthropometric data, laboratory parameters, lung function, blood gases and comorbidities were assessed prior to initiation of home mechanical ventilation. Patients were classified as anaemic based on haemoglobin (Hb) levels (Hb<12/13 g/dl, female patients/male patients). Patients with known causes for anaemia were excluded. RESULTS: In patients with CRF the prevalence of anaemia was 13.3% and not different between RD (11.5%) and OD (14.7%) (p=0.276). A sex-related difference occurred only in OD [7.9% (f) vs. 17.3% (m); p=0.035]. Patients with OD and anaemia presented with higher age (p=0.003), pH (p=0.014) and arterial oxygen pressure (PaO(2) ) (p=0.012), lower body mass index (BMI) (p=0.011) and total protein (p=0.012) and higher rates of coronary heart disease (p=0.01), cardiac arrhythmia (p=0.014) and diabetes mellitus (p=0.003) in comparison to non-anaemic patients. In patients with RD anaemia was associated with higher age, (p=0.008), pH (p=0.011) and lower leucocytes numbers (p=0.006). CONCLUSIONS: Anaemia is frequent not only in COPD but also in other severe respiratory diseases combined with CRF. It was associated with advanced age, several comorbidities, impaired nutritional state and elevations of pH and PaO(2) , probably because of hyperventilation. Its prognostic impact has to be elucidated in future studies.
