Health-related quality of life in patients with lower limb amputation – an assessment of the measurement properties of EQ-5D-3L and EQ-5D-5L using data from the Swedish Amputation and Prosthetics Registry

Figures & data

Table 1. Background characteristics for patients with complete responses on the EQ-5D descriptive system at the six-month follow-up after unilateral lower limb amputation, by subsample.

	Total sample	Subsamples
	All respondents n = 685	EQ-5D-3L n = 425	EQ-5D-5L n = 260	p-value
Sex, n (%)				0.627^a
Men	464 (67.7)	285 (67.1)	179 (68.8)
Women	221 (32.3)	140 (32.9)	81 (31.2)
Age at amputation (years), mean (SD)	72.0 (13.5)	71.3 (14.4)	73.2 (11.9)	0.070^b
Age at amputation (years), n (%)				0.180^c
<50	41 (6.0)	29 (6.8)	12 (4.6)
50–59	66 (9.6)	43 (10.1)	23 (8.8)
60–69	153 (22.3)	104 (24.5)	49 (18.8)
70–79	213 (31.1)	117 (27.5)	96 (36.9)
80–89	156 (22.8)	96 (22.6)	60 (23.1)
90–100	56 (8.2)	36 (8.5)	20 (7.7)
Amputation procedure, n (%)				0.182^a
Primary amputation	661 (96.5)	407 (95.8)	254 (97.7)
Re-amputation	24 (3.5)	18 (4.2)	6 (2.3)
Level of amputation, n (%)				0.359^a
TTA	519 (75.8)	327 (76.9)	192 (73.8)
TFA/KD	166 (24.2)	98 (23.1)	68 (26.2)
Underlying diagnosis^d, n (%)				0.590^a
Diabetes and/or vascular disease	551 (82.9)	338 (82.2)	213 (83.9)
Other	114 (17.1)	73 (17.8)	14 (16.1)

^aChi-square test.

^bIndependent sample t-test.

^cMann-Whitney U test.

^dThe number of patients with unknown underlying diagnosis was 14 (3%) EQ-5D-3L respondents and 6 (2%) EQ-5D-5L respondents.

Note: SD: Standard Deviation; TTA: transtibial amputation; TFA: transfemoral amputation; KD: knee disarticulation. Diabetes/vascular disease includes “diabetes with or without vascular disease,” “atherosclerosis without diabetes,” “other peripheral vascular diseases.” Other includes “trauma,” “tumor,” “infection unrelated to diabetes or vascular disease,” “acquired deformity,” “congenital deformity,” “other,” and “unknown.”

Table 2. Self-reported health outcomes at six-month follow-up after unilateral lower limb amputation, by subsample.

		Subsamples
	Total sample	EQ-5D-3L	EQ-5D-5L	p-value
Overall situation as amputee, n (%)				0.348^a
Very good	78 (12.0)	52 (13.2)	26 (10.2)
Good	314 (48.3)	188 (47.7)	126 (49.2)
Neither good nor bad	165 (25.4)	101 (25.6)	64 (25.0)
Bad	64 (9.8)	38 (9.6)	26 (10.2)
Very bad	29 (4.5)	15 (3.8)	14 (5.5)
Residual limb pain, n (%)				0.049^a
None	334 (50.0)	213 (52.1)	121 (46.7)
Yes, a little	157 (23.5)	100 (24.4)	57 (22.0)
Yes, moderate	126 (18.9)	73 (17.8)	53 (20.5)
Yes, a lot	51 (7.6)	23 (5.6)	28 (10.8)
Phantom limb pain, n (%)				<0.0001^a
None	218 (32.7)	159 (39.1)	59 (22.7)
Yes, a little	209 (31.3)	121 (29.7)	88 (33.8)
Yes, moderate	164 (24.6)	87 (21.4)	77 (29.6)
Yes, a lot	76 (11.4)	40 (9.8)	36 (13.8)
LCI-5, median (IQR)
LCI-5 basic	20 (24–9)	21 (23–10)	19 (24–9)	0.835^a
LCI-5 advanced	9 (19–2)	9 (20–2)	9 (18–1)	0.387^a
LCI-5 total	28 (43–12)	28.5 (43.75–12)	27 (42–11)	0.642^a
Prosthetic use score, median (IQR)	32 (51–6)	32 (51–8)	32 (52–4)	0.395^a

^aMann-Whitney U test.

Note: IQR: interquartile range; LCI-5: Locomotor Capabilities Index-5.

Figure 1. Distribution of responses on the EQ-5D dimensions at six-month follow-up after a unilateral amputation, among EQ-5D-3L (3L) respondents (n = 425) and EQ-5D-5L (5L) respondents (n = 260).

Histograms presenting patients’ responses to EQ-5D-3L and EQ-5D-5L, respectively. The response patterns show that reported problems were more commonly related to mobility, usual activities, and pain/discomfort, than to self-care and anxiety/depression, and that EQ-5D-5L provides more detailed information about the severity of problems.

Table 3. Informativity, as assessed by Shannon’s indices, by EQ-5D version.

	Shannon’s index (H΄)		Shannon’s Evenness index (J΄)
	EQ-5D-3L	EQ-5D-5L	EQ-5D-3L	EQ-5D-5L
Mobility	1.09	2.21	0.69	0.95
Self-care	1.15	1.83	0.73	0.79
Usual activities	1.45	2.23	0.91	0.96
Pain/discomfort	1.30	1.96	0.82	0.85
Anxiety/depression	1.22	1.80	0.77	0.78

Note: The range for Shannon’s index (H΄) depends on the number of possible response options per dimension, i.e., min–max is 0–1.58 (0–2.32) for the EQ-5D-3L (EQ-5D-5L). The range for Shannon’s Evenness index (J΄) is 0–1.

Table 4. Spearman’s rank correlation coefficients (rho) between responses to the EQ-5D versions (sum score, dimensions, and EQ VAS [5L]), and LCI-5, prosthetic use score, residual limb pain, phantom limb pain, and overall situation as an amputee.

	EQ-5D-3L						EQ-5D-5L
	Sum score	Mo	Sc	Ua	Pd	Ad	Sum score	Mo	Sc	Ua	Pd	Ad	EQ VAS
LCI-5 basic	−0.426**	−0.467**	−0.468**	−0.306**	−0.028	−0.099*	−0.484**	−0.530**	−0.490**	−0.362**	−0.050	−0.102	0.215**
LCI-5 advanced	−0.408**	−0.424**	−0.459**	−0.321**	−0.031	−0.078	−0.479**	−0.462**	−0.501**	−0.344**	−0.118	−0.091	0.275**
LCI-5 total	−0.429**	−0.456**	−0.477**	−0.317**	−0.036	−0.093	−0.492**	−0.511**	−0.516**	−0.358**	−0.080	−0.095	0.240**
Prosthetic use score	−0.420**	−0.449**	−0.289**	−0.253**	−0.134**	−0.206**	−0.504**	−0.488**	−0.384**	−0.323**	−0.246**	−0.148*	0.334**
Residual limb pain^a	0.156**	0.063	−0.103*	−0.015	0.386**	0.096	0.353**	0.143*	0.196**	0.259**	0.438**	0.319**	−0.307**
Phantom limb pain^a	0.158**	0.085	−0.044	−0.014	0.391**	0.093	0.249**	0.072	0.005	0.194**	0.445**	0.219**	−0.114
Overall situation as amputee^a	0.482**	0.327**	0.186**	0.320**	0.224**	0.398**	0.522**	0.349**	0.286**	0.463**	0.339**	0.415**	−0.462**

*p < 0.05 (2-tailed), **p < 0.01 (2-tailed). Note: Mo: Mobility; Sc: Self-care; Ua: Usual activities; Pd: Pain/discomfort; Ad: Anxiety/depression. Bold numbers indicate variables between which a correlation was hypothesized. The thresholds used for interpreting the correlation coefficients (rho) were: absent (rho < 0.2), weak (0.2 ≤ rho < 0.35), moderate (0.35 ≤ rho < 0.5), and strong (rho ≥ 0.5) correlation.

^aSimilar to EQ-5D dimensions and sum score, high values indicate more problems or worse health.

Table 5. Mean EQ-5D index values, t-statistics, and relative efficiency of EQ-5D-3L and EQ-5D-5L, by known groups (amputation level and underlying diagnosis).

EQ-5D version	Classification	n	EQ-5D index, mean (SD)	t-statistics	p-value	RE
	Amputation level
EQ-5D-3L	TTA	327	0.564 (0.31)	1.469	0.134	0.538
	TFA/KD	98	0.512 (0.31)
EQ-5D-5L	TTA	192	0.550 (0.31)	2.003	0.046	1
	TFA/KD	68	0.462 (0.33)
	Underlying diagnosis
EQ-5D-3L	Diabetes and/or vascular disease	338	0.549 (0.31)	−0.210	0.834	–
	Other	73	0.558 (0.30)
EQ-5D-5L	Diabetes and/or vascular disease	213	0.531 (0.32)	0.143	0.886	–
	Other	41	0.524 (0.28)

Note: TTA: transtibial amputation; TFA: transfemoral amputation; KD: knee disarticulation; SD: standard deviation; RE: relative efficiency; 95% CI: confidence interval at the 0.05 level of significance. Relative efficiency was not calculated by groups of underlying diagnoses since the t-statistics were non-significant (p > 0.05) for both EQ-5D-3L and EQ-5D-5L.

Data availability statement

Access to data is restricted by Swedish law. General information about obtaining access to data is available from the corresponding author Olivia Ernstsson upon request.