Association of factor expression levels with health-related quality of life and direct medical costs for people with haemophilia B

Figures & data

Table 1. Demographic and clinical characteristics of the study cohort.

Characteristic, n (%) unless noted	HRQoL (n = 191)	EU Costs (n = 226)	US Costs (n = 181)
Age
Mean (SD)	36.8 (15.0)	38.6 (16.5)	34.3 (14.3)
Median (range)	34 (18, 89)	35 (18, 84)	31 (18, 89)
Country
United States	79 (41)	–	181 (100)
France	43 (23)	55 (24)	–
Italy	36 (19)	69 (31)	–
Germany	20 (10)	42 (19)	–
Spain	8 (4)	30 (13)	–
United Kingdom	5 (3)	29 (13)	–
BMI
Mean (SD)	25.4 (7.2)	24.6 (4.3)	31.4 (19.9)
Haemophilia severity
Mild (>25–40%)	22 (12)	28 (12)	12 (7)
Mild-moderate (>5–25%)	62 (32)	72 (32)	94 (52)
Moderate (1–5%)	45 (24)	44 (19)	54 (30)
Severe (<1%)	62 (32)	82 (36)	21 (12)
Baseline FEL, IU/dL
Mean (SD)	10.1 (11.4)	9.6 (11.0)	10.4 (9.7)
Median (range)	4.0 (0.3, 40.0)	4.0 (0.2, 38.0)	7.0 (0.5, 40.0)
ABR
Mean (SD)	2.8 (4.6)	2.9 (4.5)	1.7 (2.0)
Median (range)	2 (0, 50)	2 (0, 50)	1 (0, 15)
Problem joints
None	109 (57)	115 (51)	107 (59)
1	42 (22)	64 (28)	54 (30)
≥2	40 (21)	47 (21)	20 (11)
Comorbidities
Anxiety	19 (10)	26 (12)	25 (14)
Depression	16 (8)	16 (7)	18 (10)
Type 2 diabetes mellitus	8 (4)	7 (3)	7 (4)
Osteoarthritis	15 (8)	12 (5)	8 (4)
Osteoporosis	3 (2)	2 (1)	1 (1)
HIV	1 (1)	0	1 (1)
Hepatitis B	4 (2)	3 (1)	1 (1)
Hepatitis C	3 (2)	7 (3)	1 (1)

BMI, body mass index; EU, European Union; FEL, factor expression level; HB, haemophilia B; HIV, human immunodeficiency virus; HRQoL, health-related quality of life; SD, standard deviation; US, United States.

Table 2. Association between FEL and HRQoL (Tobit model; AIC, 148.6126).

Covariate	Change in HRQoL (SE)^a (n = 191)	P value
FEL	0.006 (0.002)	.003
Age	–0.005 (0.001)	<.001
BMI	0.006 (0.003)	.062
HIV (present)	–0.590 (0.376)	.118
HBV (present)	0.029 (0.163)	.859
HCV (present)	0.081 (0.198)	.683

AIC, Akaike Information Criterion; BMI, body mass index; FEL, factor expression level; HBV, hepatitis B virus; HCV, hepatitis C virus; HIV, human immunodeficiency virus.

^aCoefficient represents the average marginal effect at the mean.

Table 3. Association between FEL and direct medical costs.

Covariate	Change in EU costs (SE)^a (n = 226)	P value	Change in US costs (SE)^a (n = 181)	P value
FEL	€–108.42 (21.10)	<.001	$–529.17 (288.80)	.067
Age	€8.02 (10.66)	.452	$98.73 (132.26)	.455
BMI	€11.36 (30.01)	.705	$145.45 (105.82)	.169
HIV (present)	€0	–	$–29,804.66 (25,299.13)	.239
HBV (present)	€–1,823.33 (1,582.98)	.249	$–9,175.74 (23,061.23)	.691
HCV (present)	€–609.16 (1,029.44)	.554	$–26,934.82 (24,792.09)	.277

AIC, Akaike Information Criterion; BMI, body mass index; FEL, factor expression level; HBV, hepatitis B virus; HCV, hepatitis C virus; HIV, human immunodeficiency virus; SE, standard error.

^aCoefficient represents the average marginal effect at the mean.

Figure A1. Scatterplot of FEL and HRQoL score.

Figure A2. HRQoL Tobit model RCS output. P-value to test for non-linear relationship between FEL and ABR: P = .7991

Figure A3. EU direct medical cost RCS output. P-value to test for non-linear relationship between FEL and ABR: P = .002

Figure B1. Second Tobit model RCS output. P-value to test for non-linear relationship between FEL and ABR: P < .0001

Table B1. Association between FEL and HRQoL (Second Tobit model; AIC, 97.1051).

Covariate	Coefficient^a	Standard error	P value
FEL	0.011	0.002	<.001
Age	–0.005	0.001	<.001
BMI	0.005	0.003	.078
HIV (present)	–0.618	0.343	.074
HBV (present)	–0.020	0.149	.893
HCV (present)	0.108	0.181	.552

AIC, Akaike Information Criterion; BMI, body mass index; FEL, factor expression level; HBV, hepatitis B virus; HCV, hepatitis C virus; HIV, human immunodeficiency virus.

^aCoefficient represents the average marginal effect at the mean.

Data availability statement

The data that support the findings of this study may be available from HCD Economics, Ltd but restrictions apply to the availability of these data, which were used under license for the current study, and so are not publicly available. Data may be available from the authors upon reasonable request and with permission of HCD Economics Ltd.