Table 3 Frailty instruments used by eligible studies

11 Factor Modified Frailty Index (mFI-11)

Accumulating deficit model

This scale accounts for 11 variables, and 1 point is given for each variable present:

Non-independent functional status

History of diabetes mellitus

History of chronic obstructive pulmonary disease

History of congestive heart failure

History of myocardial infarction

History of percutaneous coronary intervention, cardiac surgery, or angina

Hypertension requiring the use of medication

Peripheral vascular disease or rest pain

Impaired sensorium

Transient ischemic attack or cerebrovascular accident without residual deficit

Cerebrovascular accident with deficit

Cloney et al. [35]

Imaoka et al. [36]

Youngerman, et al. [17]

5 Variable Modified Frailty index (mFI-5)

Accumulating deficit model

The mFI-5 is calculated using the following variables: -non-independent functional status,

-Diabetes mellitus,

-Chronic obstructive pulmonary disease or current pneumonia,

-Congestive heart failure, and

-Hypertension requiring medication.

Non-independent functional status is defined by the NSQIP database as requiring assistance for any activities of daily living, including feeding, dressing, bathing, and mobility.

Each factor contributes one point for an mFI-5 score between 0 and 5, with increasing scores implying increasing frailty.

Henry et al. [38]

Huq et al. [15]

Therioult et al. [40]

Sastry et al. [39]

John Hopkins Frailty Instrument

Phenotype deficit model

This phenotype model of frailty includes the 5 components of the HFS: shrinking, weakness, exhaustion, low activity, and slowed walking speed

Harland et al. [37]

Johns Hopkins

Adjusted Clinical Groups

(JHACG) frailty-defining

diagnosis indicator

Phenotype deficit model

Johns Hopkins Adjusted Clinical Groups frailty-defining diagnosis indicator. The JHACG frailty-defining diagnosis indicator uses a set of 10 clinical clusters:

malnutrition, dementia, vision impairment, decubitus ulcer, urine control, weight loss, fecal control, social support, difficulty walking, and history of a fall.

Shahrestani et al. [16]