← Caregiver glossary · Medical concepts
A clinical syndrome of decreased physiologic reserve, often measured by unintentional weight loss, weakness (grip strength), exhaustion, slowness (gait speed), and low physical activity. Frailty drives many treatment decisions in older adults — frail patients tolerate surgery, chemotherapy, and aggressive interventions much less well, and outcomes data supports gentler approaches.
Frailty is a medical concept distinct from old age, illness, or disability. It's a syndrome of diminished reserve — the body's ability to recover from stressors (surgery, infection, hospitalization, dehydration, even a flu shot) is reduced. The two most-used measurement frameworks: the Fried Frailty Phenotype (5 criteria: weight loss, exhaustion, weakness, slow gait, low activity; 3+ = frail, 1-2 = pre-frail) and the Frailty Index (a count of accumulated deficits across 30-70 domains, expressed as a fraction).
Frailty matters because it predicts outcomes better than age alone. An 85-year-old who scores robust on the frailty assessment may tolerate a major surgery better than a 70-year-old who scores frail. Treatment decisions that have shifted with frailty-informed practice:
• **Surgery**: frail patients have higher complication rates, longer hospital stays, more nursing-home discharges. For elective procedures, frailty triggers more careful weighing of benefit vs. recovery burden. • **Cancer treatment**: frail patients tolerate full-dose chemotherapy poorly. Dose adjustments, less-intensive regimens, or palliative-focused care often produce better quality-of-life outcomes. • **Hospitalization**: frail patients are more likely to develop delirium, lose function, and not return to baseline. Hospital-at-home programs and ICU-avoidance strategies are growing precisely because of this. • **Medications**: deprescribing reviews (removing medications whose risks now outweigh benefits) are routine in frail patients.
Frailty is partially reversible. Resistance exercise (with PT or a properly-trained personal trainer), nutritional optimization (protein at every meal, vitamin D), and treatment of underlying conditions (anemia, depression, sleep apnea) can move patients from frail to pre-frail and from pre-frail to robust. For families: the geriatrician (not the regular PCP) is the right physician to run a frailty assessment and prescribe interventions.
In geriatric assessment ("she's scoring as frail"); in pre-operative consultations; in cancer treatment-planning discussions when chemotherapy intensity is being weighed.
Terms families frequently confuse with frailty.
Comorbidity is the LIST of other conditions a patient has. Frailty is a SYNDROME — a state of reduced physiologic reserve. A patient can have many comorbidities and not be frail; a patient can have few comorbidities and still be frail. Both matter but they're different lenses on the patient's clinical state.
ADLs are functional tasks (bathing, dressing, eating). Frailty is the underlying physiologic state that often leads to ADL deficits but isn't identical to them. A patient can be frail while still independent in ADLs (a warning sign); a patient can be ADL-dependent without being frail (e.g., post-stroke rehabilitating).
See also: all glossary terms · conditions by name · step-by-step playbooks