Читать книгу Pathy's Principles and Practice of Geriatric Medicine - Группа авторов - Страница 554

In 1968, the World Health Organization (WHO) formally established the definition of anaemia. It was categorized as a haemoglobin level less than 13 g/dL in men and less than 12 g/dL in women.¹ The normal haemoglobin range is adjusted for children, pregnancy, gender, smokers, and those who live at higher altitudes, but there have yet to be any large studies specifically focused on normal haemoglobin values in older people. Additionally, the original cohort used to establish the normal values of haemoglobin at the population level excluded elderly patients, and thus controversy exists regarding normal values for older people. A natural decline in haemoglobin levels in older adults is accepted, but at this time, it is not clear if this happens due to the ageing process, underlying chronic disease, or some other unknown cause. While the absolute value of haemoglobin is important when considering if someone is anaemic, it is also important to take into account the trend of haemoglobin in an individual and whether there has been a substantial change from previous values.

Anaemia in older people is often underdiagnosed and undertreated despite being associated with increased morbidity and poor quality of life in older adults.² Older people with anaemia have been found to have added impairments in activities of daily living and functional status,³ increased weakness and fatigue,⁴ and higher rates of frailty,⁵ cognitive decline,⁶ depression,³ and fractures.⁷ In addition, hospitalized older adults with anaemia have longer lengths of stay and increased readmission rates.^8,9 While anaemia is very common in those with advanced age, it is not considered a normal aspect of ageing, and older adults with anaemia should undergo a workup to evaluate the cause of anaemia and establish a diagnosis. Once a diagnosis is established, a treatment plan can be implemented. Treatment of anaemia typically requires a multi‐faceted plan. Resolution may be difficult to achieve – particularly if the anaemia is due to underlying chronic inflammation and disease.

Anaemia is typically classified by either underlying aetiology¹⁰ or morphology and size of red blood cells (RBCs) as determined by the mean‐corpuscular volume (MCV) of haemoglobin. If classified by aetiology, typical groupings consist of impaired production of RBCs (nutritional deficiencies, chronic inflammation, and clonal disorders), acute loss of RBCs (bleeding), accelerated RBC destruction (haemolytic and sickle cell anaemia), and ‘unexplained’ anaemia (Figure 22.1). If classified by morphology, the MCV of RBCs is used, and classifications include microcytic, normocytic, and macrocytic anaemias. It is more common to use the classification system relying on underlying aetiology and important to recognize that the MCV often does not reflect the underlying anaemia pathogenesis. For example, in vitamin B12 deficiency anaemia, RBCs may be either normocytic or macrocytic, but it is commonly thought of as a purely macrocytic anaemia. In nutritional deficiencies, MCV is frequently in the normal range, particularly early in the disease course, and can also be normal when multiple diseases are present concurrently, making it less useful for establishing an aetiology.