How should clinical care of the aged differ?

1) begins in the third decade and occurs in each organ system independently of changes in other organ systems and is influenced by diet, environment, and personal habits as well as by genetic factors. From this concept it follows that individuals become more dissimilar as they age, belying any stereotype of age; that an abrupt decline in any system or function is always due to disease rather than “normal ageing”; that “normal ageing” can be attenuated by modification of risk factors such as increased blood pressure, smoking, and sedentary lifestyle; and that “healthy old age” is not a paradox for, in the absence of disease, homoeostenosis results in neither symptoms nor restrictions in activities of daily living at any age. These deceptively simple ideas have important implications for care, research, education, and health policy. We will focus on the clinical implications, summarised as six principles of care for the elderly. Because of impaired physiological reserve in older patients, disease often presents at an earlier stage At any age, symptoms reflect an imbalance between disease severity and intrinsic compensatory mechanisms (figure 1). Since these mechanisms are generally intact in younger individuals, disease can progress further before causing symptoms. In older patients compensatory mechanisms may be impaired by pre-existing disease or by physiological decline and even mild disease may tip the balance—eg, heart failure may be precipitated by mild hyperthyroidism, significant cognitive dysfunction by mild hypercalcaemia, urinary retention by mild prostatic enlargement, and nonketotic hyperosmolar coma by mild glucose intolerance. Thus treatment of the underlying disease may be easier. An old person with hypercalcaemia-induced cognitive dysfunction often needs a drug, not parathyroidectomy, those with hyperosmolar coma do not usually need chronic insulin, patients with urinary retention often do not require prostatectomy, and congestive heart failure often can be managed by diet or thiazides rather than potent diuretics. 2