Table 2.

Examples of instruments with predictive validity in the context of respiratory disease

Measure	Administration Type	Resources	Description	Scoring	Properties in Respiratory Disease
Clinical Frailty Scale (68, 85)	Clinician assessed	∼3–5 min	Comprises clinical descriptions to guide scoring of frailty. Scores are allocated on the basis of clinical judgment, considering physical fitness, active disease symptoms, dependency, and cognitive status.	1 (very fit) to 9 (terminally ill), with scores of ≥5 indicating frailty	Predictive of hospitalization and mortality in people with COPD (46).
Frailty index (46)	Chart review	∼3–5 min	Chart review of ≥30 items on the basis of presence of comorbidities, symptoms, disabilities, or deficiency in health. The number of items present is expressed as a proportion.	A cut point ≥0.25 is generally used to define frailty	Predictive of hospitalization (46) and mortality in people with COPD (46, 86) and ILD (87).
4-m gait speed	Single physical task	∼5 min Stopwatch Measured course	Speed of walking over a flat, unobstructed 4-m course, expressed in meters per second.	<0.8 m/s is commonly used to indicate frailty in community-dwelling older adults (44)	Reliable, valid, and predictive of hospitalization and mortality in people with COPD (88–90) and ILD (91, 92). Responsive to change after pulmonary rehabilitation in people with COPD (93) and ILD (94).
Timed Up and Go test	Single physical task	∼5 min Stopwatch Chair Measured course	Measures the time taken in seconds for a participant to stand from seated, walk to a marker 3 m away, turn, walk back to the chair, and then sit down again.	A threshold of >10 s is commonly used for community-dwelling older people (44); >8 s is suggested for people with COPD (41)	Valid and reliable in people with COPD (95) and ILD (96). Responsive to change after pulmonary rehabilitation (83) and can distinguish between people with COPD with and without frailty (41).
Short Physical Performance Battery (97)	Multiple physical tasks	∼8–10 min Stopwatch Chair Measured course	Comprises three physical tests: static balance, 4-m gait speed, and 5 sit-to-stands. Each is scored 0–4 and totaled, for a maximum score of 12.	Although thresholds vary, commonly, scores ⩽7 indicate frailty and 8 or 9 indicate prefrailty	Responsive to change after rehabilitation in people with COPD (98) and ILD (27, 99). Predictive of mortality in people with COPD (40, 43).
Physical frailty phenotype (34)	Multiple physical tasks and self-report	∼10–15 min Stopwatch Chair Measured course Handheld dynamometer Participant questionnaire	Measures the five phenotype components through self-report questions about weight loss, exhaustion, and physical activity and physical measurement of weakness (grip strength) and slowness (4-m gait speed).	Total scores range from 0 to 5; scores of ≥3 indicate frailty, and scores of 1 and 2 indicate prefrailty	Responsive to change after pulmonary rehabilitation (15) and predictive of adverse events (39, 43) in people with COPD. Predictive of mortality in people with COPD (11, 43, 100) and ILD (101, 102).

Definition of abbreviations: COPD = chronic obstructive pulmonary disease; ILD = interstitial lung disease.

Content was not derived from a systematic review.