Burden of Wilson Disease among patients and care partners in the United States: results from a cross-sectional survey

Figures & data

Table 1. Sociodemographic and health characteristics among survey participants (patients with WD and WD-CPs) and matched NHWS general population cohorts.

Characteristics	Patients with WD n = 37	Matched GP (NHWS)^a n = 111	WD-CPs n = 53	Matched GP-CPs (NHWS)^a n = 159
Age, years
Mean (SD)	44.7 (17.4)	45.4 (16.6)	44.6 (9.2)	45.0 (10.7)
Median (min-max)	45.0 (18.0-75.0)	45.0 (19.0-75.0)	42.0 (35.0-78.0)	42.0 (21.0-80.0)
Gender, n (%)^b
Female	25 (67.6)	73 (65.8)	36 (67.9)	108 (67.9)
Employment status, n (%)
Employed	18 (48.6)	75 (67.6)	43 (81.1)	113 (71.1)
Retired	8 (21.6)	17 (15.3)	2 (3.8)	12 (7.5)
Not employed	11 (29.7)	19 (17.1)	8 (15.1)	34 (21.4)
BMI, n (%)
Underweight (<18.5 kg/m^2)	0	2 (1.8)	0	18 (11.3)
Normal weight (18.5-24.9 kg/m^2)	27 (73.0)	77 (69.4)	6 (11.3)	42 (26.4)
Overweight (25.0-29.9 kg/m^2)	7 (18.9)	22 (19.8)	1 (1.9)	36 (22.6)
Obese (≥30.0 kg/m^2)	1 (2.7)	4 (3.6)	1 (1.9)	50 (31.4)
Decline to provide height or weight	2 (5.4)	6 (5.4)	45 (84.9)	13 (8.2)
Patient’s insurance status, n (%)
Private insurer	26 (70.3)	67 (60.4)	36 (67.9)	–
Public insurer^c	11 (29.7)	26 (23.4)	17 (32.1)	–
Not sure	0	1 (0.9)	0	–
Not insured	0	17 (15.3)	0	–

Abbreviations. BMI, body mass index; GP, general population; GP-CPs, general population care partners; NHWS, National Health and Wellness Survey; SD, standard deviation; WD, Wilson disease; WD-CPs, Wilson disease care partners.

^a Note: NHWS cohorts were matched in a ratio of 3:1 to WD cohorts using propensity scoring. The multivariable logistic regression model used to estimate propensity scores included age, sex, region, education level, marital status, children living in households, and BMI category (for patients only) as explanatory variables.

^b One WD-CP declined to report their gender.

^c Public insurance includes: Medicaid, Medicare, Veterans Affairs (VA)/CHAMPVA, CHAMPUS/TRICARE.

Table 2. Diagnostic, clinical, and treatment characteristics of patients with WD and patients of WD-CPs.

Characteristic	Patients with WD	WD-CPs
Age at the date of onset of first symptoms related to WD^a, years	n = 37	n = 6
Mean (SD)	20.0 (11.3)	8.8 (3.9)
Median (min–max)	18.0 (5.0-47.0)	9.0 (2.0-13.0)
Age at date diagnosed with WD by physician, years^a	n = 34	n = 7
Mean (SD)	20.9 (12.4)	11.6 (4.4)
Median (min–max)	18.0 (4.0-49.0)	10.0 (7.0-20.0)
Age at date diagnosed with WD by physician, split at 18^a, n (%)	n = 34	–
<18 years	18 (52.9)	–
≥18 years	16 (47.1)	–
Age at date diagnosed with WD by physician, split at 26^a, n (%)	n = 34	–
<26 years	22 (64.7)	–
≥26 years	12 (35.3)	–
Years since diagnosed with WD by physician^b	n = 34	–
Mean (SD)	25.1 (14.9)	–
Median (min-max)	21.5 (3.0-53.0)
Months between the date of first symptoms leading to seek medical help/treatment and date diagnosed with WD by physician^b	n = 26	–
Mean (SD)	12.9 (31.7)	–
Median (min-max)	2.5 (0.0-161.0)	–
Type of physician that diagnosed WD, n (%)	n = 37	n = 53
Gastroenterologist	15 (40.5)	6 (11.3)
Hepatologist	8 (21.6)	31 (58.5)
Medical geneticist	3 (8.1)	11 (20.8)
General practitioner	3 (8.1)	2 (3.8)
Others^c	7 (18.9)	0
Not sure	1 (2.7)	3 (5.7)
Medications ever taken for WD, n (%)	n = 37	n = 53
Penicillamine	25 (67.6)	46 (86.8)
Trientine	21 (56.8)	45 (84.9)
Zinc acetate, Rx	26 (70.3)	49 (92.5)
Zinc acetate, OTC	17 (45.9)	23 (43.4)
Others	2 (5.4)	0
Not sure	0	2 (3.8)
Medications currently taken for WD, n (%)	n = 37	–
Penicillamine	8 (21.6)	–
Trientine	11 (29.7)	–
Zinc acetate, Rx	14 (37.8)	–
Zinc acetate, OTC	9 (24.3)	–
Others	2 (5.4)	–
None	1 (2.7)	–
Time from WD diagnosis to date started prescription medication, months^b	–	n = 7
Mean (SD)	–	0.1 (0.4)
Median (min–max)	–	0.0 (0.0–1.0)
Time from WD diagnosis to date started penicillamine, months^d	n = 15	–
Mean (SD)	12.5 (47.2)	–
Median (min-max)	0.0 (0.0–183.0)	–
Time from WD diagnosis to date started trientine, months^d	n = 11	–
Mean (SD)	47 (103.8)	–
Median (min-max)	3.0 (0.0–323.0)
Time from WD diagnosis to date started zinc, months^d	n = 17	–
Mean (SD)	100.1 (139.5)	–
Median (minmax)	5.0 (0.0-371.0)	–

Abbreviations. OTC, over-the-counter; Rx, prescription; SD, standard deviation; WD, Wilson disease; WD-CPs, Wilson disease care partners.

^a Patients with WD were asked about the date they first begin experiencing symptoms related to their Wilson disease that made them want to seek medical help/treatment, and WD-CPs were asked about the date when the person they care for first began to show signs and symptoms of WD.

^b Data provided for 34 WD (3 unsure) and/or 7 WD-CP (46 unsure).

^c Patients with WD: Other diagnosing physicians included neurologist (n = 2), opthamologist (n = 2), and ‘other’ category (n = 3).

^d Data missing due to being unsure for 2, 3, and 6 patients with WD for pencillamine, trientine, and, zinc, respectively.

Table 3. Comorbidity and humanistic burden among patients with WD and WD-CPs and matched NHWS general population cohorts.

Characteristic	Patients with WD n = 37	Matched GP (NHWS) n = 111	WD-CPs n = 53	Matched GP-CPs (NHWS) n = 159
CCI score, mean (SD)	1.5 (2.0)**	0.3 (0.7)	0.2 (0.7)**	0.8 (1.2)
CCI score, n (%)
0	18 (48.6)**	87 (78.4)	49 (92.5)**	97 (61.0)
1	6 (16.2)**	18 (16.2)	1 (1.9)**	41 (25.8)
2	3 (8.1)**	3 (2.7)	2 (3.8)**	9 (5.7)
≥3	10 (27.0)**	3 (2.7)	1 (1.9)**	12 (7.5)
Comorbidities, n (%)
Chronic liver disease	10 (27.0)**	0	–	–
Cirrhosis	10 (27.0)**	0	–	–
Migraine	8 (21.6)*	8 (7.2)	–	–
High cholesterol	7 (18.9)	24 (21.6)	–	–
High blood pressure	7 (18.9)	13 (11.7)	–	–
Depression	6 (16.2)	20 (18.0)	–	–
NASH	5 (13.5)**	1 (0.9)	–	–
Sleep conditions experienced in past 12 months, n (%)
Any sleep problem	22 (59.5)**	37 (33.3)	20 (37.7)	–
Insomnia	10 (27.0)	17 (15.3)	3 (5.7)	–
Idiopathic hypersomnia	1 (2.7)	3 (2.7)	–	–
Narcolepsy	1 (2.7)	3 (2.7)	–	–
Sleep apnea	2 (5.4)	4 (3.6)	–	–
Sleep difficulties (others)^a	13 (35.1)*	17 (15.3)	18 (34.0)	–
PHQ-9 score, mean (SD)	5.1 (5.7)	6.6 (7.9)	3.0 (3.2)**	9.6 (8.0)
PHQ-9 score segment, n (%)
0–4, none-minimal depression	22 (59.5)	59 (53.2)	37 (69.8)**	56 (35.2)
5–9, mild depression	11 (29.7)	21 (18.9)	15 (28.3)**	30 (18.9)
10–14, moderate depression	1 (2.7)	11 (9.9)	1 (1.9)**	30 (18.9)
15–19, moderately severe depression	1 (2.7)	8 (7.2)	0	22 (13.8)
20–27, severe depression	2 (5.4)	12 (10.8)	0	21 (13.2)
GAD-7, mean (SD)	4.4 (5.6)	5.1 (5.8)	3.7 (3.9)**	8.2 (6.2)
GAD-7 score segment, n (%)
0–4, none-minimal anxiety	24 (64.9)	60 (54.1)	34 (64.2)**	56 (35.2)
5–9, mild anxiety	7 (18.9)	29 (26.1)	14 (26.4)**	32 (20.1)
10–14, moderate anxiety	2 (5.4)	11 (9.9)	5 (9.4)**	45 (28.3)
15–21, severe anxiety	4 (10.8)	11 (9.9)	0	26 (16.4)
EQ-5D index score, mean (SD)	0.845 (0.146)	0.806 (0.195)	0.886 (0.086)**	0.705 (0.235)
EQ VAS, mean (SD)	75.5 (17.8)	76.5 (22.6)	68.0 (12.9)	64.7 (28.6)
EQ-5D-5L, n (%)
Mobility, any problems	7 (18.9)	25 (22.5)	2 (3.8)**	77 (48.4)
Self-care, any problems	4 (10.8)	12 (10.8)	0	56 (35.2)
Usual activities, any problems	14 (37.8)	35 (31.5)	2 (3.8)**	79 (49.7)
Pain/discomfort, yes	18 (48.6)	63 (56.7)	15 (28.3)**	123 (77.4)
Anxiety/depression, yes	15 (40.5)	62 (55.8)	30 (56.6)*	105 (66.0)
CRA^b, mean (SD), n (%)
Impact on health subscale	–	–	11.2 (1.8)	10.8 (2.5)
Caregiver’s esteem subscale	–	–	23 (3.3)**	25.7 (5.1)
Impact on schedule subscale	–	–	15.8 (3.9)	17.21 (5.0)
Impact on finance subscale	–	–	10 (1.9)	9.5 (2.5)
Lack of family support subscale	–	–	14.4 (3.5)	15.5 (4.3)

Abbreviations. CCI, Charlson Comorbidity Index; CRA, Caregiver Reaction Assessment; EQ-5D-5L, 5-Level EQ-5D version; GAD-7, 7-item Generalized Anxiety Disorder Assessment; GP, general population; GP-CPs, general population care partners; NASH, non-alcoholic steatohepatitis; NHWS, National Health & Wellness Survey; PHQ-9, 9-item Patient Health Questionnaire; SD, standard deviation; VAS, Visual Analog Scale; WD, Wilson disease; WD-CPs, Wilson disease care partners.

^a “Sleep difficulties (others)” category for patients with WD and matched NHWS GP included difficulties other than insomnia, idiopathic hypersomnia, narcolepsy, and sleep apnea; for WD-CPs it included difficulties other than insomnia, narcolepsy and apnea.

^b CRA was reported only for n = 71 matched NHWS GP-CPs because the NHWS respondents only took the CRA if the respondent was a caregiver of an adult relative with Alzheimer’s disease, autism, bipolar disorder, cancer, Crohn’s disease, chronic kidney disease on dialysis, dementia, epilepsy, macular degeneration, multiple sclerosis, muscular dystrophy, osteoporosis, Parkinson’s disease, schizophrenia, or stroke.

* p < .05;

** p < .01.

all statistics reported relative to GP or GP-CP cohorts, for patients and WD-CP analyses, respectively.

Table 4. Economic burden among patients with WD and WD-CPs and matched NHWS general population cohorts.

Characteristics	Patients with WD	Matched GP (NHWS)	WD-CPs	Matched GP-CPs (NHWS)
HCRU, visits in past 6 months, n (%)	n = 37	n = 111	n = 53^a	n = 159
ER visits	8 (21.6)	20 (18.0)	0	50 (31.5)
Hospitalizations	3 (8.1)	13 (11.7)	1 (1.9)**	53 (33.3)
Traditional HCP visits^b	34 (91.9)**	71 (64.0)	5 (9.4)**	134 (84.3)
HCP seen in past 6 months, n (%)	n = 37	n = 111	–	–
Gastroenterologist	16 (43.2)**	5 (4.5)	–	–
General practitioner/family practitioner/internist	24 (64.9)	57 (51.4)	–	–
Hepatologist	12 (32.4)**	1 (0.9)	–	–
Ophthalmologist	6 (16.2)**	2 (1.8)	–	–
None of the above	2 (5.4)**	38 (34.2)	–	–
HCRU, number of visits in past 6 months, mean (SD)	n = 36	n = 111	n = 9	n = 159
ER visits	0.3 (0.5)	0.3 (0.7)	0	0.8 (1.6)
Hospitalizations	0.2 (0.7)	0.2 (0.6)	0.1 (0.3)**	0.8 (1.7)
Traditional HCP visits^a	n = 37	n = 111	n = 8	n = 159
	2.9 (2.7)*	1.6 (3.1)	2 (2.1)*	4.2 (7.1)
	n = 37	n = 111	–	–
Gastroenterologist	0.6 (0.8)**	0.05 (0.2)	–	–
General practitioner/family practitioner/internist	1.1 (1.1)	0.70 (1.0)	–	–
Hepatologist	0.4 (0.6)**	0.01 (0.1)	–	–
Ophthalmologist	0.2 (0.5)*	0.02 (0.1)	–	–

Abbreviations. ER, emergency room; GP, general population; GP-CPs, general population care partners; HCP, healthcare provider; HCRU, healthcare resource utilization; NHWS, National Health & Wellness Survey; SD, standard deviation; WD, Wilson disease; WD-CPs, Wilson disease care partners.

^a N = 44 WD-CPs reported not being able to recall how many times they went to an ER or were hospitalized for their own medical conditions in the past 6 months, and N = 45 WD-CPs reported not being able to recall how many times they had an HCP visit in the past 6 months.

^b Traditional providers include gastroenterologists, general practitioners/family practitioners/internists, gynecologist/obstetricians, hepatologists, neurologists, ophthalmologists, psychiatrists/psychologists/counselors.

* p < .05;

** p < .01.

all statistics reported relative to GP or GP-CP cohorts, for patients and WD-CP analyses, respectively.

Figure 1. WPAI among survey participants (patients with WD and WD-CPs) and matched NHWS general population cohorts GP, general population; GP-CPs, general population care partners; NHWS, National Health & wellness Survey; WD, Wilson disease; WD-CPs, Wilson disease care partners; WPAI, work productivity and activity impairment.

Data availability statement

The participants of this study did not give written consent for their data to be shared publicly, so due to the sensitive nature of the research supporting data is not available.