What is the Difference Between Cachexia and Sarcopenia?

Cachexia and sarcopenia are both muscle wasting disorders, but they have distinct differences in their definitions, mechanisms, and associated conditions. Here are the main differences between cachexia and sarcopenia:

  • Definition: Sarcopenia is defined as the loss of muscle mass and function associated with aging, while cachexia is defined as weight loss due to an underlying illness.
  • Mechanism: Sarcopenia is associated with the aging process, while cachexia is associated with a pathological, underlying condition.
  • Comorbid Condition: Sarcopenia can be present with or without other comorbid conditions, while cachexia is characterized by the presence of other comorbid conditions.
  • Functional Limitation: Both conditions are associated with functional limitations, but the limitations are more severe in cachexia.
  • Inflammation: Inflammation is a key feature in cachexia, while it is not as prominent in sarcopenia.
  • Fat Mass: Fat mass is increased in sarcopenia and decreased in cachexia.
  • Protein Degradation: Protein degradation is increased in both conditions, but it is more prominent in cachexia.
  • Resting Energy Expenditure: Resting energy expenditure is decreased in sarcopenia and increased in cachexia.
  • Anorexia: Anorexia is present in both conditions, but it is more severe in cachexia.

In summary, sarcopenia is an age-related muscle loss and function decline, while cachexia is a weight loss due to an underlying illness, often characterized by increased inflammation and a more severe functional limitation.

Comparative Table: Cachexia vs Sarcopenia

Cachexia and sarcopenia are both conditions characterized by muscle loss, but they have distinct differences in their definitions, mechanisms, and clinical implications. Here is a table summarizing the differences between cachexia and sarcopenia:

Feature Cachexia Sarcopenia
Definition Weight loss >5% in 6 months, with depletion of muscle and/or fat mass Muscle mass <2SD of young healthy population, decreased muscle function
Mechanism Pathologic, associated with underlying illness Aging-related
Comorbid condition +++ +/−
Functional limitation +++ ++
Inflammation ++ -
Fat mass Decreased Increased
Protein degradation ++++ -/+
Resting Energy Expenditure Increased Decreased
Anorexia ++ +

Cachexia is a metabolic syndrome associated with underlying illness and is characterized by weight loss and muscle depletion, while sarcopenia is an age-related loss of muscle mass and function. Inflammation is a key feature of cachexia, whereas it is not a prominent factor in sarcopenia. Sarcopenia is more commonly observed in older adults and is associated with decreased muscle function, while cachexia often co-occurs with other medical conditions and is associated with increased functional limitations.