Validity and measurement equivalence of EQ-5D-5L questionnaire among heart failure patients in Malaysia: a cohort study

Figures & data

Figure 1. Flow diagram for patient recruitment.

Table 1. Baseline demographics of heart failure patients.

Variables	Total (N = 200)	Malay (n = 98)	English (n = 52)	Chinese (n = 50)	p-value^a
Mean age (SD)	61.4 (13.7)	59.9 (12.9)	60.9 (11.9)	64.7 (16.4)	0.090
≥60 years, n (%)	121 (60.5)	54 (55.1)	34 (65.4)	33 (66.0)	0.309
Gender, n (%)					0.070
Male	148 (74.0)	75 (76.5)	42 (80.8)	31 (62.0)
Female	52 (26.0)	23 (23.5)	10 (19.2)	19 (38.0)
Ethnicity, n (%)					<0.05*^#
Malay	110 (55.0)	85 (86.7)	25 (48.1)	–
Chinese	56 (28.0)	–	6 (11.5)	50 (100.0)
Indian	33 (16.5)	12 (12.2)	21 (40.4)	–
Others	1 (0.5)	1 (1.0)	–	–
Married, n (%)					<0.05*
No	28 (14.0)	6 (6.1)	7 (13.5)	15 (30.0)
Yes	169 (84.5)	77 (78.6)	44 (84.6)	34 (68.0)
Unknown	3 (1.5)	1 (2.0)	1 (1.9)	1 (2.0)
Employed (n, %)					0.236
No	147 (73.5)	38 (76.0)	35 (71.2)	33 (66.0)
Yes	53 (26.5)	12 (24.0)	15 (28.8)	17 (34.0)
Income group (n, %)					0.466^#
B40 (<USD 1,017)	185 (92.5)	91 (92.9)	49 (94.2)	45 (90.0)
M40 (USD 1,017 - USD 2,299)	4 (2.0)	2 (2.0)	2 (3.8)	–
T20 (≥USD 2,299)	6 (3.0)	2 (2.0)	1 (1.9)	3 (6.0)
Unknown	5 (2.5)	3 (3.1)	–	2 (4.0)
Smoking (n, %)					0.710
Non-smoker	97 (48.5)	46 (46.9)	23 (44.2)	28 (56.0)
Active smoker	42 (21.0)	20 (20.4)	13 (25.0)	9 (18.0)
Ex-smoker	59 (29.5)	31 (31.6)	16 (30.8)	12 (24.0)
Unknown	2 (1.0)	1 (1.0)	–	1 (2.0)
Mean BMI, kg/m^2 (SD)	26.4 (6.1)	26.9 (6.2)	27.2 (6.2)	24.7 (5.7)	0.076
Underweight (<18.5 kg/m^2), n (%)	9 (4.5)	2 (2.0)	1 (1.9)	6 (12.0)
Normal (18.5-22.9 kg/m^2), n (%)	47 (23.5)	22 (22.4)	12 (23.1)	13 (26.0)
Overweight (23-27.4 kg/m^2), n (%)	62 (31.0)	33 (33.7)	12 (23.1)	17 (34.0)
Obese (≥27.5 kg/m^2), n (%)	71 (35.5)	35 (35.7)	24 (46.1)	12 (24.0)
Unknown, n (%)	11 (5.5)	6 (6.1)	3 (5.8)	2 (4.0)
Reason for HF hospitalization					0.240
De novo	64 (32.5)	26 (26.5)	18 (34.6)	21 (42.0)
Recurrent	135 (67.5)	72 (73.5)	34 (65.4)	29 (58.0)
Primary cause of heart failure, n (%)					0.176
Non-ischemic	67 (33.5)	37 (37.8)	12 (23.1)	18 (36.0)
Ischemic	133 (66.5)	61 (62.2)	40 (76.9)	32 (64.0)
Years since HF diagnosis, n (%)					0.405^#
<1 year	125 (62.5)	56 (57.1)	34 (65.4)	35 (70.0)
1-4 years	58 (29.0)	33 (33.7)	13 (25.0)	12 (24.0)
≥5 years	13 (6.5)	9 (9.2)	2 (3.8)	2 (4.0)
Unknown	4 (2.0)	–	3 (5.8)	1 (2.0)
Mean length of hospital stay, days (SD)	5.2 (4.0)	5.0 (4.4)	5.2 (3.2)	5.7 (3.9)	0.240
Mean CCI, scores (SD)	3.7 (1.7)	3.7 (1.6)	3.8 (1.7)	3.6 (1.7)	0.815
Comorbidities, n (%)
Hypertension	130 (65.0)	69 (70.4)	34 (65.4)	27 (54.0)	0.1407
Dyslipidemia	73 (36.5)	36 (36.7)	24 (46.2)	13 (26.0)	0.1069
Type 2 Diabetes	128 (64.0)	68 (69.4)	36 (69.2)	24 (48.0)	<0.05*
Obesity	71 (35.5)	35 (35.7)	24 (46.2)	12 (24.0)	0.051
Prior ischemic heart disease	118 (59.0)	54 (55.1)	35 (67.3)	29 (58.0)	0.347
Prior stroke / TIA	23 (11.5)	13 (13.3)	5 (9.6)	5 (10.0)	0.744
Atrial fibrillation	49 (24.5)	20 (20.4)	14 (26.9)	15 (30.0)	0.393
Prior CABG	15 (7.5)	5 (5.1)	4 (7.7)	6 (12.0)	0.297^#
Prior PCI	41 (20.5)	22 (22.4)	15 (28.8)	4 (8.0)	<0.05*
Prior device implantation	12 (6.0)	4 (4.1)	5 (9.6)	3 (6.0)	0.404^#
Liver diseases	23 (11.5)	8 (8.2)	6 (11.5)	9 (18.0)	0.207
Lung diseases (COPD / Asthma)	17 (8.5)	6 (6.1)	6 (11.5)	5 (10.0)	0.406
Anemia	103 (51.5)	52 (53.1)	22 (42.3)	29 (58.0)	0.259
Mean eGFR at admission, ml/min/1.73m^2	58.6 (25.0)	55.5 (26.3)	63.9 (21.7)	59.0 (25.2)	0.186
>90, n (%)	38 (19.0)	17 (17.3)	13 (25.0)	8 (15.4)
60–89, n (%)	67 (33.5)	31 (31.6)	15 (28.8)	21 (40.4)
30–59, n (%)	62 (31.0)	30 (30.6)	20 (38.5)	12 (23.1)
15–29, n (%)	25 (12.5)	15 (15.3)	4 (7.7)	6 (11.5)
<15, n (%)	8 (4.0)	5 (5.1)	0 (0)	3 (5.8)
Mean LVEF, % (SD)	26.6 (7.6)	27.0 (7.6)	25.9 (8.1)	26.4 (7.3)	0.677
≤10%, n (%)	3 (1.5)	1 (1.0)	1 (1.9)	1 (2.0)
11–20%, n (%)	52 (26.0)	25 (25.5)	14 (26.9)	13 (26.0)
21–30%, n (%)	87 (43.5)	42 (42.9)	21 (40.4)	24 (48.0)
31–40%, n (%)	58 (29.0)	30 (30.6)	16 (30.8)	12 (24.0)
NYHA at 1-month post-discharge, n (%)					0.611
Class I	72 (36.0)	32 (32.7)	19 (36.5)	21 (42.0)
Class II	55 (27.5)	29 (27.5)	13 (25.0)	13 (26.0)
Class III	20 (10.0)	13 (10.0)	5 (9.6)	2 (4.0)
Class IV	26 (13.0)	11 (13.0)	7 (13.5)	8 (16.0)
Missing	27 (13.5)	13 (13.3)	8 (15.4)	6 (12.0)
Median utility score (IQR)
Admission	0.09 (-0.17, 0.48)	0.11 (-0.18, 0.48)	0.03 (-0.23, 0.21)	0.18 (-0.09, 0.51)	0.091
Discharge	0.77 (0.50, 0.92)	0.76 (0.41, 0.92)	0.72 (0.63, 0.94)	0.80 (0.65, 0.92)	0.376
1-month post-discharge^b	0.85 (0.59, 1.00)	0.85 (0.58, 1.00)	0.93 (0.56, 1.00)	0.85 (0.65, 1.00)	0.479
Mean VAS score (SD)
Admission	40 (20, 50)	45 (20, 50)	30 (19.3, 42.5)	40 (30, 50)	0.080
Discharge	70 (50, 80)	70 (51.3, 80)	65 (50, 80)	70 (55, 80)	0.173
1-month post-discharge^b	75 (60, 85)	75 (60, 85)	75 (67.5, 86.3)	70 (58.8, 80)	0.395

Data presented in n (%) unless otherwise stated. eGFR was calculated based on MDRD equation. 1MPD: 1-month post-discharge; BMI, body mass index; BP, blood pressure; CABG, coronary artery bypass graft; CCI, Charles Comorbidity Index, COPD, chronic obstructive pulmonary disease; eGFR, estimated glomerular filtration rate; HF, heart failure; LVEF, left ventricular ejection fraction; MI, myocardial infarction; n, number of patients; N, total number of patients; PCI, percutaneous coronary intervention; SD, standard deviation; TIA, transient ischemic attack. MYR to USD conversion using the exchange rate of MYR1 = USD 0.21 as of 19/10/2023.

^aChi-square test (when each cell frequency ≥ 5%) and Fisher’s test (when each cell frequency < 5%) were used for categorical variables; Kruskal-Wallis test (non-parametric) were used for numerical variables.

^#Fisher’s test was used to examine the differences among different languages.

*Statistically significant with p-value <0.05.

^bn = 129 for 1-month follow up (Malay: 43; English: 42; Chinese: 44).

Figure 2. Confirmatory factor analysis of EQ-5D-5L dimensional scores.

Table 2. Known group validity of EQ-5D-5L utility and VAS scores.

Groups	Utility scores		VAS scores
	Coeff. Estimates (95%CI)	p-value	Coeff. Estimates (95%CI)	p-value
(A) Unadjusted model
Age
<60 years old	Reference		Reference
≥60 years old	−0.093 (−0.175, −0.010)	0.027	−5.47 (−9.59, −1.34)	0.009
NYHA
Class I	Reference		Reference
Class II	−0.151 (−0.224, −0.079)	<0.001	−10.61 (−15.03, −6.20)	<0.001
Class III	−0.382 (−0.485, −0.280)	<0.001	−13.49 (−19.72, −7.26)	<0.001
Class IV	−0.532 (−0.625, −0.439)	<0.001	−19.03 (−24.67, −13.39)	<0.001
(B) Adjusted model 1^a
Age
<60 years old	Reference		Reference
≥60 years old	−0.114 (−0.195, −0.033)	0.006	−5.28 (−9.46, −1.11)	0.013
NYHA
Class I	Reference		Reference
Class II	−0.164 (−0.236, −0.092)	<0.001	−11.01 (−15.47, −6.56)	<0.001
Class III	−0.373 (−0.474, −0.271)	<0.001	−13.77 (−20.04, −7.49)	<0.001
Class IV	−0.536 (−0.628, −0.444)	<0.001	−18.84 (−24.54, −13.14)	<0.001
(C) Adjusted model 2^b
Age
<60 years old	Reference		Reference
≥60 years old	−0.099 (−0.180, −0.018)	0.016	−9.53 (−9.53, −1.14)	0.013
NYHA
Class I	Reference		Reference
Class II	−0.161 (−0.234, −0.088)	<0.001	−10.61 (−15.10, −6.12)	<0.001
Class III	−0.348 (−0.455, −0.242)	<0.001	−13.43 (−19.95, −6.91)	<0.001
Class IV	−0.533 (−0.629, −0.437)	<0.001	−17.24 (−23.13, −11.35)	<0.001

Coeff: coefficient; 95%CI = 95% confidence interval; 1MPD: 1-month post discharge.

^aAdjusted for language, rater, and center for each group, accounting for repeated measures and within-patient variance.

^bAdjusted for age, gender, ethnicity, language, rater, center for each group, accounted for repeated measures and within-patient variance.

Table 3. Responsiveness and minimal clinically important difference of EQ-5D-5L at different time-points.

	Utility score				VAS score
Responsiveness	Admission vs Discharge^a		Discharge VS 1MPD^b^f		Admission vs Discharge^a		Discharge VS 1MPD^b^f
Effect size (95% CI)^c
Glass’ delta	1.30 (1.07, 1.52)		0.15 (−0.06, 0.36)		1.38 (1.15, 1.61)		0.17 (−0.05, 0.38)
Cohen’s D	1.38 (1.16, 1.60)		0.15 (−0.05, 0.35)		1.44 (1.22, 1.66)		0.16 (−0.04, 0.36)
Hedges G	1.38 (1.16, 1.60)		0.15 (−0.05, 0.35)		1.44 (1.22, 1.65)		0.16 (−0.04, 0.36)
SRM	1.27 (1.08, 1.45)		0.06 (−0.08, 0.20)		1.20 (1.02, 1.38)		0.14 (0.00, 0.28)
MCID	Admission	Discharge	1MPD^f	Mean	Admission	Discharge	1MPD^f	Mean
MCID (half SD)	0.20			0.20	10.40			10.40
MCID (one SEM)^d	0.20	0.18	0.19	0.19	11.98	11.04	11.84	11.62
Mean MCID				0.19				11.01
MDCi	0.56	0.49	0.52	0.53	33.21	30.60	32.81	32.21
MDCg	0.04	0.03	0.04	0.04	2.35	2.16	2.49	2.34
MCID:MDC (half SD)^e				5.16				4.45
MCID:MDC (one SEM)^e				4.98				4.97

CI: confidence interval; MCID: minimal clinically important difference; MDC: minimal detectable change; MDC_i: minimal detectable change for individual; MDC_g: minimal detectable change for group. SEM: standard error measurement.

^aEffect size is measured by the mean change of scores between discharge and admission.

^bEffect size is measured by the mean change of scores between 1-MPD and discharge.

^cEffect size was interpreted as large (≥0.8), moderate (0.5–0.79) or small (<0.5) with 95% confidence interval.

^dMCID (one SEM) was calculated using r = 0.731 (utility scores) and r = 0.668 (VAS scores).

^eMCID:MDC >1 indicates real minimal important change, instead of measurement error.

^fAll data involving 1MPD were calculated using the complete datasets, where N = 173.

Figure 3. Response distribution of utility and VAS scores for different languages.

Figure 4. Influence of language versions of EQ-5D-5L on utility and VAS scores.