Ideally, the care of older patients should be grounded in the best available evidence about the benefits and harms of treatments. Unfortunately, high-quality evidence rarely exists. Good studies of a clinical condition often exclude older persons. Even when older persons are included, enrollment tends to be limited to healthy robust older persons who may little resemble the patient in front of you.
As a result, one can rarely practice true evidence-based medicine in older patients. Instead, one needs to examine available evidence and then critically assess the extent to which the evidence might apply to the patient being treated. To best make optimal clinical decisions, clinicians need to understand the limitations of applying the clinical research literature to their older patients, and thoughtfully apply existing evidence to the individual patient they are treating.
The Challenges With Current Evidence
Clinicians are generally trained to consider outcomes from clinical trials as the gold standard for how to apply evidence-based medicine to clinical care. Ideally, clinical trials would include any patient who is a logical candidate for the therapy being examined. Unfortunately, most clinical trials include only idealized patients, excluding patients in whom the therapy has a greater risk of side effects, or patients who are at risk for not completing the trial. However, these nonidealized patients who are commonly excluded from clinical research are just the type of patients seen in geriatric practice, and in whom the therapies will often be used and marketed.
Zulman et al have described a framework that outlines the reasons older persons may be excluded from clinical trials. These reasons include explicit age exclusions, implicit age exclusions, and unintentional age exclusions.
Many studies have age-specific cutoffs in which all subjects above a defined age are denied enrollment. Although these exclusions are common, they can almost never be justified. Most studies with explicit age exclusions present absolutely no rationale to justify the exclusion.
An explicit age exclusion is only justifiable if one clearly would not offer a therapy in clinical practice to persons older than a particular age. In actual practice, most therapies tested in younger patients are eventually offered to older patients. Furthermore explicit age exclusions ignore the vast heterogeneity in health in older persons.
More often, the reasons for excluding older subjects are more subtle. Many studies without an age cutoff have exclusion criteria that differentially restrict the entry of older patients, particularly older patients who are more medically complex. Examples of implicit age exclusions include comorbidity, functional impairments, cognitive impairments, and inability to give informed consent.
Treatment studies often focus on the effect of a specific treatment on health outcomes in persons with a specific condition. But most older people have multiple conditions. Yet ...