Alvan Feinstein coined the term comorbidity in 1970,1 defining it as the presence of ‘a distinct additional clinical entity’. Charlson's index sought to measure the health impact of various comorbidities and more recently others have underlined the difficulties that comorbidity presents for the production and implementation of clinical guidelines, for the delivery of whole-person care, and for the assessment of the quality of care.3,4 In this month's BJGP, chronic disease and comorbidity are examined from various different standpoints, with consideration of important aspects of the management of chronic renal disease, of cardiovascular disease, and of diabetes.
Comorbidity can be thought of in a number of ways. Some comorbidities are contingent on pre-existing conditions, such as heart failure in patients …