This is currently defined as “a multifactorial syndrome characterized by an ongoing loss of skeletal muscle mass (with or without loss of fat mass) that cannot be fully reversed by conventional nutritional support and leads to progressive functional impairment”.
It is a serious but under-recognised condition. It has been described in many different chronic illnesses. The prevalence is high, ranging from 5-15% in chronic heart failure or chronic obstructive pulmonary disease to 60–80% in advanced cancer.
By population prevalence, the most frequent cachexia subtypes are in order: chronic obstructive pulmonary disease, cardiac (in chronic heart failure), cancer and chronic kidney disease. (See Table 1 below)
It has been noted in patients with infectious diseases, such as HIV/AIDS, malaria, and tuberculosis, as well as many chronic conditions like cystic fibrosis, liver cirrhosis, Crohn’s disease, rheumatoid arthritis, stroke, and neurological degenerative disease. It has also been noted in patients after extensive traumatic injury and sepsis.
Using data from the Nationwide Inpatient Sample, the annual prevalence of cachexia admissions to community hospitals in the USA has been estimated at over 160,000 cases. In this study, the median duration of stay was 6 days, compared with 3 days for non-cachexia admissions. These patients also experienced greater loss of function than those admitted with other diagnoses. Globally, the overall prevalence of cachexia (due to any disease and not necessarily leading to hospital admission) is around 1% of the patient population, i.e. around 9 million people are affected.
Focus on cancer cachexia
Many forms of cancer present with a complex metabolic profile characterised by loss of lean body mass specifically known as cancer cachexia. The physical impact of this contributes to decreased patient quality of life, treatment success and survival due to gross alterations in protein metabolism, increased oxidative stress and systemic inflammation. The psychological impact also contributes to decreased quality of life for both patients and their families. Combination therapies that target multiple pathways, such as eicosapentaenoic acid administered in combination with exercise, appetite stimulants, antioxidants or anti-inflammatories, have potential in the treatment of this complex syndrome and require further development.
It affects 50–80% of cancer patients, depending on the tumour type, and that leads to substantial weight loss, primarily from loss of skeletal muscle and body fat.
A total of 390 patients with advanced cancer were included in a recent study. The prevalence was 35.9%. The prevalence was highest in pancreatic cancer (88.9%), followed by gastric cancer (76.5%) and esophageal cancer (52.9%). Cachectic patients have a significantly lower overall quality of life and a higher symptom burden. Cancer cachexia was rarely recognized and clinical management for this was very inadequate.
Moreover, it may account for up to 20% of cancer deaths.
In this perspective, cancer cachexia may be identified as both a causal and a complicating comorbidity of cancer because of its strict association with the pathophysiological changes induced by the tumour in the host. Unlike other comorbidities, however, there is now compelling evidence suggesting that cancer cachexia may be prevented or at least delayed in its presentation, provided that a comprehensive tailored medical approach is adopted.