Anaemia is a common condition with prevalence of 20% and is greater in patients over 85 years of age (Goodnough and Schrier, 2014). It varies in elderly patients depending on various factors such as an individual's socioeconomic status (Styszynski et al, 2018), psychological state (Hosseini et al, 2018), dementia diagnosis (Andreev et al, 2020), and available support. This condition may affect almost one in two elderly individuals in nursing homes or those admitted to hospital (Gaskell et al, 2008) and also can be highly associated with elderly patients in palliative care as anaemia was found in 77% of men and 68% of women in a study by Dunn et al (2003). Anaemia in elderly patients is often multifactorial (Thomas, 2017) and usually mild (haemoglobin level 11-12.9 g/dl for men and 11-11.9 g/dl for women) (Gaskell et al, 2008); however, the most common cause of this condition is iron deficiency due to malnutrition, decreased iron absorption, chronic gastrointestinal blood loss or chronic inflammatory conditions (Andrès et al, 2008; Girelli et al, 2018; Cappellini et al, 2020).
The prevalence of pressure ulcers (PUs) is significantly increased in elderly patients (Børsting et al, 2018; Olivo et al, 2020) and is also related to factors such as dementia (Jaul et al, 2019), socioeconomic status (Azevedo Macena et al, 2017; Liao et al, 2019), long-term conditions (Lenche et al, 2016; Galivanche et al, 2020), malnutrition (Neloska et al, 2016), low oxygen level and tissue ischemia (Jaul et al, 2018; Kim et al, 2019). One in four elderly individuals developed PUs in a study by Rasero et al (2015) across different settings such as hospitals, nursing homes and home care.
Anaemia and decreased haemoglobin levels have been identified as significantly associated with PU development in the elderly population (Nadukkandiyil et al, 2019). There is a need to investigate the impact of anaemia on the process of PU healing and consider possible improvements in PU management as the current guidelines do not directly include any measures and actions associated with anaemia and only consider the impact of oxygenation deficits and impaired nutritional status on the risk of PU as a recommendation (National Institute for Health and Care Excellence (NICE), 2014; European Pressure Ulcer Advisory Panel et al, 2019; NICE, 2020).
Aetiology and pathophysiology of anaemia in PU development and healing
Anaemia is defined by the World Health Organization (WHO)(2011) as a blood disorder in which haemoglobin levels are below 120 g/litre in females and 130 g/litre in males. This is a condition associated with a decreased ability of erythrocytes (red blood cells) to transport oxygen from the lungs to the body's tissues (Cappellini and Motta, 2015). Erythrocytes accommodate an iron–containing protein, haemoglobin, which is able to bind oxygen molecules to haeme groups (Kosmachevskaya and Topunov, 2018). A diminished oxygen supply to the body's tissues due to a low concentration of haemoglobin may lead to local hypoxia, which has a destructive impact on certain tissues depending on their metabolic activity and oxygen demand (Thomas and Lumb, 2012; Hare et al, 2013). A significant decrease of oxygen concentration may also cause tissue continuity disruption and cell necrosis, which can result in PU initiation. The prevalence of oxygen decrease is higher in the elderly population due to altered skin elasticity and increased fragility (Gefen, 2008; Sree et al, 2019; Blackburn et al, 2020).
A PU is caused by sustained pressure, which decreases the oxygen supply to the tissue and leads to ischaemia and necrosis (Edsberg et al, 2016; Lumbers, 2019; Mervis and Phillips, 2019). The significant factor is the length of time pressure is applied during specific occurrences, for example, when a patient needs to be in the same position, such as proning (Stephen-Haynes and Maries, 2020) or positioning for surgical purposes (Walton-Geer, 2009). Anaemia in patients can significantly increase the development of a PU as oxygen concentration is already lower due to diminished haemoglobin and oxygen supply, resulting in tissue hypoxia (Thomas and Lumb, 2012; Sree et al, 2019).
A decreased level of oxygen at the cellular level caused by anaemia has a negative impact on the PU healing rate. Oxygen plays specific roles in all of the stages of the wound healing process (Kimmel et al, 2016) and is essential in cell metabolism, which may be altered in the elderly (Catic, 2018; Giorgi et al, 2018). Oxygen is also converted into reactive oxygen species (ROS) in the mitochondrial oxidative phosphorylation process, which reduces as the person gets older. ROS regulates different cellular signalling pathways associated with each phase of the healing process (Kimmel et al, 2016) which involves: platelet aggregation and vasoconstriction in the haemostasis phase (Masselli et al, 2020); vasodilation, chemotaxis for phagocytic cells, and anti-inflammatory response in the inflammatory phase (Mittal et al, 2014; Staiculescu et al, 2014); and angiogenesis, proliferation and differentiation of cells, and extracellular matrix formation in the proliferation phase (Staiculescu et al, 2014). ROS also regulates formation and maturation in the remodelling phase (Saxena et al, 2019). Additionally, the PU healing process is compromised by both intrinsic and extrinsic factors as a result of the ageing process (Mitchell, 2020).
Anaemia may also affect PU healing differently in each individual. Some difficulties and problems may depend on the PU aetiology and pathophysiology, the staging of the PU damage and physical, psychological and socioeconomic factors. These need to also be considered according to the biopsychosocial model as the PU impact on patient's quality of life is always multidimensional (Kurtz and Silverman, 1996; Morton and Phillips, 2016; European Pressure Ulcer Advisory Panel et al, 2019; Mervis and Phillips, 2019).
Anaemia may be classed by mean corpuscular volume (MCV) of erythrocytes (Table 1), or by pathogenic mechanisms related to the production and loss of these cells (Table 2). There can be some dissimilarity in the influence of specific types of anaemia on PU healing and the appropriate treatments may need to be considered depending on the aetiology of anaemia as many factors can affect the wound healing process (Guo and Dipietro, 2010).
Table 1. Anaemia classification by red blood cell volume
| Group | Example |
|---|---|
| Microcytic | Iron deficiency, thalassaemia or anaemia of chronic disease (eg autoimmune diseases, cancers, chronic infections such as HIV/AIDS, chronic kidney disease, inflammatory bowel disease (MCV is decreased to below 82 fl)) |
| Macrocytic | Megaloblastic, vitamin B12 and folate deficiency, liver disorders or alcohol-related (MCV is increased to above 98 fl) |
| Normocytic | Renal insufficiency, haemolytic or related to some chronic diseases (MCV is within the normal range of 82–98 fl) |
MCV=mean corpuscular volume
Source: Moreno Chulilla et al, 2009; Thomas, 2017
Table 2. Anaemia classification by red blood cell production
| Hyporegenerative: bone marrow production of appropriate red blood cells is diminished, which may be caused by lack of iron, vitamin B12 or folic acid/folate |
| Regenerative: production of red blood cells is increased by an appropriate response by the bone marrow to low red blood cell level |
Source: Moreno Chulilla et al, 2009
Anaemia associated with nutritional deficiencies and PU healing
Iron-deficiency anaemia is the most common form of anaemia in the elderly (Halawi et al 2017; Cappellini et al, 2020). This is microcytic anaemia caused by a reduced value of MCV (Thomas, 2017) and is associated with a decreased ability of haemoglobin production due to an insufficient level of iron in the body (absolute iron deficiency) or diminished iron supply to bone marrow (functional iron deficiency) (Lopez et al, 2016). This can affect PU healing differently than other types of anaemia. Iron deficiency is an additional factor that negatively influences wound healing. Iron is required to assist with various molecular mechanisms in the skin such as oxidative stress processes and ultraviolet-induced damages in the skin (Wright et al, 2014) and cell apoptosis (Kurz et al, 2008). In the wound healing process, iron deficiences can affect cellular proliferation and differentiation (Wright et al, 2014; Wlaschek et al, 2019), protein synthesis, and regulation of macrophage function during the inflammatory phase (Soares and Hamza, 2016; Recalcati et al, 2019).
Iron concentration is elevated in damaged tissue when a wound is healing (Coger et al, 2019) and there is an increased local iron deposition in hard-to-heal wounds (Tchanque-Fossuo et al, 2017). This specifically increased iron demand may also be a contributing factor to anaemia in patients with a hard-to-heal PU. Fuoco et al (1997) found that patients with PU in the inflammatory phase of wound healing were more likely to be anaemic, and this anaemia disappeared after healing. In addition, a hard-to-heal PU (an inflammatory condition) may lead to anaemia of chronic disease (Fraser, 2010).
There are other significant nutritional deficiencies that may cause anaemia such as vitamin B12 (cobalamin) and vitamin B9 (folate). Both are common nutritional disorders in the elderly (Watson et al, 2018; Marchi et al, 2020) caused by malnutrition, malabsorption, some chronic conditions and medication (Nagao and Hirokawa, 2017) and may lead to macrocytic anaemia associated with an increased value of MCV and an impaired development of abnormally large, immature erythrocytes, or megaloblasts (Thomas, 2017). However, macrocytic anaemia may also be non-megaloblastic if caused by specific conditions such as liver dysfunction, hypothyroidism or myelodysplastic syndrome but not by vitamin B12 or folate deficiency (Nagao and Hirokawa, 2017). PU healing may be specifically affected by B12 and folate deficiencies in addition to a negative influence by impaired oxygen transportation to tissues in patients with megaloblastic anaemia. These vitamins play important roles in vascular functions such as cellular homocysteine metabolism, nitric oxide bioavailability and vasodilation (Gilfix, 2005; Blom and Smulders, 2011; Stanhewicz and Kenney, 2017). Vitamin B12 and folate deficiencies may lead to vascular dysfunction and occlusions (Haynes, 2002; Haloul et al, 2020). The psychological functions of elderly individuals may also be affected in terms of cognitive deficits, depression, and pain (Baroni et al, 2019; Julian et al, 2020; Khosravi et al, 2020).
Recommendations for practice
Nurses and other health professionals need a good understanding of the causes and implications of anaemia in the context of PUs as a full holistic assessment is necessary to effectively treat elderly patients. Risk assessments for PUs should be carried out as soon as possible after the patient is admitted to hospital or community caseload and repeated as often as required based on patient acuity (European Pressure Ulcer Advisory Panel et al, 2019) or if a change occurs in the patient's condition (Mitchell, 2018). These may need to include anaemia and associated problems of this condition to achieve effective long–term PU management. There are several validated risk assessment tools used; however, these tools are not directly associated with anaemia or risk assessment for anaemia. The Waterlow assessment tool, the most commonly used in the UK, involves haemoglobin level only as one of many risk factors for PU development (Waterlow, 2005) The Malnutrition Universal Screen Tool (MUST) (Bapen, 2011), which is an accurate and valid malnutrition assessment tool for the elderly (Poulia et al, 2012), concentrates on the BMI and weight loss over time rather than significant nutritional deficiencies associated with anaemia.
The prevention and management of PU in elderly patients need to involve anaemia assessment and correction in addition to diet supplementation and repositioning (Nadukkandiyil et al, 2019); however, a holistic risk assessment on admission and at any significant change in patient's condition always should be carried out according to the NICE (2014) guideline. This may also need to involve any risks associated with anaemia and an approach based on the biopsychosocial model by considering all the physical, psychological and social factors associated with anaemia as early recognition and management of this blood disorder can have a great impact on an elderly individual's health condition (Kurtz and Silverman, 1996; Burney et al, 2016).
Conclusion
Elderly individuals are at an increased risk of anaemia of multifactorial aetiology and a higher risk of anaemia of chronic illness due to an increased iron demand associated with PUs. This blood condition has a negative influence on PU healing. Anaemia screening and correction, as well as iron supplementation, may need to be considered in the prevention and management of PU in elderly individuals. Physical, psychological and social factors are significant in the association between anaemia and PU healing based on the biopsychosocial model (Kurtz and Silverman, 1996).
Key Points
- Anaemia in elderly patients is often multifactorial but the most common cause is iron deficiency
- Reduced oxygen supply as a result of anaemia puts tissues at greater risk of damage, on top of other risk factors for pressure ulcers (PUs) present in elderly patients
- Anaemia screening and correction may need to be implemented in PU prevention and management
- Iron supplementation may need to be considered in elderly patients with PUs as they are at risk of anaemia of chronic disease due to increased iron demand
- More research is needed on how different types of anaemia contribute to PU development and problems associated with wound healing to improve prevention and treatment in elderly individuals
CPD reflective questions
- Reflect on the elderly patients with pressure ulcers you have treated. Did you assess them for anaemia?
- Do your patients have any long-term conditions that may cause anaemia
- How do you currently manage anaemia for your patients? Is there anything about your practice you would change?