Older persons live longer and healthier lives than ever before. Persons over the age of 85 are the most rapidly growing segment of the population and those over 65 will account for 20% of the population by 2030. Most clinicians will spend half or more of their time caring for older adults. Older persons vary widely in health status, prognosis, and preferences for care. Many persons in their 60s are healthy and can expect to live another 30 years or longer. Yet, chronic diseases that will cause disability and death will develop in nearly all older persons. Therefore, clinicians caring for older adults must have skills in managing multiple comorbidities and wisely guiding the patient in both "curative" and "palliative care." Comorbidities are common in older people, and the diagnostic "law of parsimony" often does not apply. For example, fever, anemia, and a heart murmur suggest endocarditic in a younger patient; however, in an older patient, three different explanations—a viral illness, unexplained anemia of aging, and aortic sclerosis—are more likely than endocarditic alone.
Disease presentation is often atypical in elderly patients. A disorder in one organ system may lead to symptoms in another, especially one that is compromised by preexisting disease. A limited number of presenting symptoms like confusion, falling, incontinence, dizziness, and functional decline predominate irrespective of the underlying disease. Thus, regardless of the presenting symptom in older people, the differential diagnosis is often similar. An 80-year-old person with new falls and confusion could have pneumonia, an acute myocardial infarction, a stroke, or a urinary tract infection. Many abnormal findings are relatively common in older people and may not be responsible for a particular symptom. Such findings can include asymptomatic bacteriuria, premature ventricular contractions, and slowed reaction time. In addition, many older patients with multiple comorbidities may have laboratory abnormalities that, while pathologic, may not be clinically important.