Table 2.

Performance of Claims-Based Surrogates of Frailty Against Clinical Frailty Assessment in the Health and Retirement Study-Medicare Data

Claims-Based Surrogates of Frailtya	Sample Size (%)	Clinical FI Mean (SD)	Clinical Frailty Phenotype
			Sensitivity	Specificity	PPV	NPV
Hospital beds and associated supplies	44 (1.4%)	0.49 (0.14)	0.06	0.99	0.73	0.82
Pressure ulcer	39 (1.3%)	0.43 (0.17)	0.04	0.99	0.59	0.82
Cachexia	< 10 (< 0.3%)	0.43 (0.11)	0.01	> 0.99	0.75	0.81
Wheelchairs, components, and accessories	63 (2.6%)	0.41 (0.15)	0.09	0.99	0.63	0.82
Adult failure to thrive	< 10 (< 0.3%)	0.36 (0.17)	0.01	> 0.99	0.57	0.81
Muscle weakness	164 (5.3%)	0.34 (0.16)	0.12	0.96	0.44	0.82
Accessories for oxygen delivery devices	149 (4.8%)	0.34 (0.16)	0.11	0.97	0.44	0.82
Debility	50 (1.6%)	0.34 (0.15)	0.04	0.99	0.48	0.81
Difficulty in walking	135 (4.4%)	0.32 (0.15)	0.10	0.97	0.44	0.82
Walking aids and attachments	130 (4.2%)	0.32 (0.14)	0.10	0.97	0.47	0.82
History of fall	56 (1.8%)	0.31 (0.16)	0.04	0.99	0.41	0.81
Transportation services including ambulance	300 (9.7%)	0.31 (0.16)	0.24	0.93	0.46	0.84
Abnormality of gait	231 (7.5%)	0.31 (0.15)	0.18	0.95	0.45	0.83
Anorexia	15 (0.5%)	0.30 (0.22)	0.01	> 0.99	0.33	0.81
Abnormal loss of weight and underweight	112 (3.6%)	0.28 (0.16)	0.08	0.97	0.44	0.82
Muscular wasting and disuse atrophy	23 (0.7%)	0.28 (0.12)	0.02	0.99	0.39	0.81
Senility without mention of psychosis	< 10 (< 0.3%)	0.26 (0.21)	< 0.01	> 0.99	0.33	0.81
Malaise and fatigue	740 (23.9%)	0.25 (0.15)	0.38	0.79	0.30	0.84

Abbreviations: FI frailty index, HCPCS Healthcare Common Procedure Coding System, ICD International Classification of Diseases, NPV negative predictive value, PPV positive predictive value, SD standard deviation

^aClaims-based surrogates of frailty were defined as occurrence of the respective codes in a 12-month period in any of the inpatient, outpatient, skilled nursing facility, home health, carrier, and durable medical equipment datasets