Frailty Index

What it is

The Rockwood frailty index counts the proportion of age-related “deficits” (symptoms, signs, lab abnormalities, functional limits, comorbid diagnoses) that an individual has, out of a list of 30–70 candidate items. Score = (deficits present) / (total assessed).

A score of >0.25 (i.e. more than 25% of items present) is broadly considered frail; intermediate scores indicate “pre-frail” status.

Why it matters

• The frailty index is one of the strongest predictors of mortality, hospitalisation, and post-procedural outcomes in older adults.
• It captures biological age in a way no single biomarker does — two 80-year-olds can differ in frailty index by a factor of 2 or more.
• It is responsive to interventions (exercise, nutrition, polypharmacy review).

The Fried phenotype (alternative)

The Fried physical-frailty phenotype is the alternative clinical-research instrument, using five criteria:

1. Unintentional weight loss.
2. Self-reported exhaustion.
3. Low grip strength.
4. Slow gait speed.
5. Low physical activity.

≥3 = frail; 1–2 = pre-frail.

What reduces frailty

• Resistance + aerobic exercise.
• Adequate protein intake.
• Treatment of depression, polypharmacy review.
• Vitamin D in deficient adults.
• Social engagement.

Related entries

Grip strength, VO2max, Sarcopenia.