A comorbidity is the presence of two or more underlying illnesses in a patient. Underlying illnesses include chronic conditions like cancer and hypertension.
Comorbid conditions can be related or unrelated to each other. With related comorbidities, one condition often presents as a result of the first condition. An example of this is diabetes or heart disease. Common heart failure comorbidities are renal insufficiency, anemia and chronic obstructive pulmonary disease.
Individuals living with comorbidities may also have a compromised immune system, require more care and experience complications, such as kidney disease or depression.