Evaluation of two frailty indices, with practical application in a vaccine clinical trial

Figures & data

Table 1. Detail of SF-36 and EQ-5D components contribution to the retrospective frailty index

Item	Scoring method based on response to question	Maximum Contribution to Frailty Index
SF-36 Q1 (General Health)	Poor = 1 Fair = 0.5 Good = 0 Very good = 0 Excellent = 0	1
SF-36 Q11A-11D (General Health)	Q11A, Q11C Definitely true = 1 Mostly true = 0.5 Don’t know = 0 Mostly false = 0 Definitely false = 0 Q11B, Q11D Definitely true = 0 Mostly true = 0 Don’t know = 0 Mostly false = 0.5 Definitely false = 1	4
SF-36 Q3I – Q3J (Physical functioning)	Limited a lot = 1 Limited a little = 0.5 Not limited at all = 0	10
SF-36 Q9A – Q9I (Vitality and Mental health)	Q9A, Q9D, Q9E, Q9H All of the Time = 0 Most of the time = 0 Some of the time = 0 A little of the time = 0.5 None of the time = 1 Q9B, Q9C, Q9F, Q9G, Q9I All of the Time = 1 Most of the time = 0.5 Some of the time = 0 A little of the time = 0 None of the time = 0	9
SF-36 Q2 Compared to one week before, how did the subject rate his/her health in general?	Much worse = 1 Somewhat worse = 0.5 Same = 0 Somewhat better = 0 Better = 0	1
EQ-5D Mobility	No Problems = 0 Some Problems = 0.5 Confined to bed = 1	1
EQ-5D Anxiety	No Anxiety = 0 Moderate Anxiety = 0.5 Extreme Anxiety = 1	1
EQ-5D Self care	No Problems = 0 Some Problems = 0.5 Inability to wash or dress himself/herself = 1	1
EQ-5D Usual activities	No Problems = 0 Some Problems = 0.5 Inability to perform usual activities = 1	1
Total		29

Table 2. Distribution of age, SF-36 physical functioning score and EQ-5D scores by frailty status according to frailty index

		Non-frail N = 236	Pre-frail N = 143	Frail N = 22
Prospectively generated FI		n (%)	n (%)	n (%)
Age	50–59 YOA	111 (82.8)	21 (15.7)	2 (1.5)
	60–69 YOA	80 (60.2)	47 (35.3)	6 (4.5)
	≥70 YOA	45 (33.6)	75 (56.0)	14 (10.4)
		Statistic	Statistic	Statistic
SF-36	Mean	90.7	71.6	40.7
physical	Standard deviation	13.18	23.59	19.84
functioning	Median	95.0	75.0	35.0
	Interquartile range	(90.0–100.0)	(55.0–90.0)	(30.0–50.0)
	Range	(25.0–100.0)	(5.0–100.0)	(5.0–95.0)
EQ-5D	Mean	0.922	0.841	0.672
	Standard deviation	0.0960	0.1408	0.1633
	Median	1.000	0.827	0.699
	Interquartile range	(0.827–1.000)	(0.800–1.000)	(0.597–0.778)
	Range	(0.467–1.000)	(0.378–1.000)	(0.308–1.000)
		Non-frail N = 192	Pre-frail N = 169	Frail N = 40
Retrospectively generated FI		n (%)	n (%)	n (%)
Age	50–59 YOA	95 (70.9)	34 (25.4)	5 (3.7)
	60–69 YOA	64 (48.1)	57 (42.9)	12 (9.0)
	≥70 YOA	33 (24.6)	78 (58.2)	23 (17.2)
		Mean (SD)	Mean (SD)	Mean (SD)
SF-36 physical functioning	Physical Function	96.4 (4.49)	75.3 (16.47)	42.8 (18.44)
	Role Physical	97.6 (6.03)	80.5 (18.21)	53.7 (25.55)
	Bodily Pain	86.6 (12.23)	70.9 (18.76)	51.5 (25.57)
	General Health	86.9 (9.44)	73.1 (13.89)	52.7 (20.45)
	Vitality	80.6 (11.24)	68.5 (13.65)	44.8 (19.91)
	Social Functioning	97.5 (7.21)	91.4 (14.03)	71.1 (26.88)
	Role Emotional	98.1 (5.65)	90.6 (13.88)	66.5 (25.58)
	Mental Health	89.1 (8.10)	83.2 (13.00)	70.1 (19.50)
EQ-5D	Utility Score	0.957 (0.0664)	0.869 (0.0916)	0.699 (0.1690)
Deficits	Comorbidities	0.94 (0.84)	2.52 (1.35)	4.00 (1.84)
	SF-36	0.47 (0.55)	3.10 (1.73)	8.94 (2.42)
	EQ-5D	0.06 (0.20)	0.37 (0.43)	1.24 (0.70)
	Total	1.47 (0.99)	5.99 (2.06)	14.2 (2.73)

N = total number of participants by frailty category; n (%) = number (percentage) of participants by age group; YOA = years of age; SD = standard deviation; SF-36 = Short Form-36; EQ-5D = EuroQol-5 Dimension

Figure 1. Distribution of the retrospectively generated frailty index

Table 3. Comparison of frailty status according to the retrospectively generated vs. prospectively specified frailty status

Prospective	Non-frail	Pre-frail	Frail	Total prospective frailty
Retrospective	n (%)	n (%)	n (%)	n (%)
Non-frail	178 (75.4)	57 (24.2)	1 (0.4)	236 (58.9)
Pre-frail	14 (9.8)	108 (75.5)	21 (14.7)	143 (35.7)
Frail	0 (0.0)	4 (18.2)	18 (81.8)	22 (5.5)
Total retrospective frailty	192 (47.9)	169 (42.1)	40 (10.0)	401 (100)

n (%) = number (percentage) of participants by frailty status

Figure 2. Mean frailty index by age and type of frailty index, assuming a linear model

Figure 3. Mean SF-36 Physical functioning score (Panel A) and Mean EQ-5D Utility score (Panel B) by days post-dose 1 by prospectively specified frailty status