Haematology in the elderly

Average life expectancy is increasing. Elderly people (>65 years) are likely to make up more than 20% of the world’s population by 2050. This effect is particularly marked in the developed world where in some countries the population over 65 years already outnumbers those below 20 years. An ageing population has implications for the practice of clinical haematology. There are significant age-related changes in haematopoiesis and haemostasis. Many blood diseases, especially malignant disorders, are more common in older people. The management of blood diseases in the elderly is often complicated by frailty, comorbidity and a need for extra care in the hospital and community.

Haematopoiesis and ageing

There is an age-associated decline in haematopoietic stem cells and haematopoietic cell function. The reasons for this are unclear and much of our knowledge is derived from studies of mouse models rather than humans. It is probable that this decline arises from a combination of accumulated genetic and epigenetic changes, alterations in the marrow microenvironment and systemic effects such as inflammation. Practical consequences of these biological changes include reduced immune function, an increased incidence of cancer, and a lesser tolerance of haematopoietic stress (e.g. chemotherapy). Stem cells from older donors are less efficient at reconstituting haematopoiesis in transplant recipients.

Anaemia is a common clinical problem in the elderly. The prevalence rises rapidly after 50 years and approaches 20% in people aged over 80 years. In general, one third of cases will have an identifiable nutritional deficiency (iron, vitamin B₁₂ or folate) (Fig 46.1). Where iron deficiency is the cause of anaemia it is often secondary to gastrointestinal blood loss, and underlying bowel pathology (e.g. colonic carcinoma) should be excluded. Another third of cases have the anaemia of chronic disease. These patients have an obvious chronic inflammatory condition (see p. 36) and will often have a measurable acute phase response (e.g. elevated C-reactive protein). In the final third of elderly patents, there is no clear cause for the anaemia (sometimes termed ‘anaemia unexplained’). This entity is a diagnosis of exclusion and has been the focus of much recent interest. A few cases may be explained by myelodysplastic syndrome or other rarer causes of anaemia but it is probably mainly due to a combination of age-related suppression of erythroid colony formation, insensitivity to erythropoietin and impaired iron utilisation.