Characteristics of patients with Wilson disease in the United States: An insurance claims database study

Table 1 Annual number of patients with Wilson disease

Calendar year	Patients with WD in the database
20161	1887
2017	2239
2018	2253
2019	2356
2020	2220
2021	2277

¹2016 was the first full year in which the specific International Classification of Diseases 10 (ICD-10) code for Wilson disease (WD) was used as a claim label in the Clarivate clearinghouse. Because two successive claims with an ICD-10 code for WD are required for case identification, it is possible that the number of incident cases in 2016 was underestimated.

Table 2 Clinical manifestations during follow-up

Type of manifestation	All patients	Patients with documented treatment	Patients with no documented treatment	P value by χ² test
	n = 5376	n = 885	n = 4491
Hepatic manifestations	1796 (33.4)	389 (44.0)	1288 (28.7)	< 0.001
Neurological manifestations	1935 (36.0)	302 (34.1)	1577 (35.1)	0.572
Psychiatric manifestations	2433 (45.3)	383 (43.3)	1977 (44.0)	0.683
At least one of the above	3829 (71.2)	649 (73.3)	3060 (68.1)	0.002

Data are n (%).

Table 3 Hospitalisations

Parameter	All patients		Patients with documented treatment	Patients with no documented treatment	P value by χ² test
	n = 5376		n = 885	n = 4491
Day hospitalisations, n (%)	4991 (92.8)	865 (97.7)		4126 (91.9)	< 0.0001
Overnight hospitalisations, n (%)	1564 (29.1)	295 (33.3)		1269 (28.3)	0.0023
Length of stay1, median (IQR)	6 (2–16)	6 (2–17)		6 (2–17)	NA
Liver transplantation, n (%)	121 (2.3)	23 (2.6)		98 (2.2)	NA

¹Excluding day hospitalisations. IQR: Interquartile range; NA: Not analysed.

Table 4 Mortality

	Insurees with WD			All insurees
Year	Total n	Deaths	Mortality rate, %	Total n	Deaths	Mortality rate, %
20161	1887	27	1.43	203060882	1991215	0.98
2017	2239	51	2.28	223313801	2341297	1.05
2018	2253	58	2.57	223828962	2420297	1.08
2019	2356	61	2.59	219088011	2390049	1.09
2020	2220	63	2.84	215457629	2461627	1.14
20212	2277	13	0.57	239164264	205313	0.09
Total	5376	273	5.08	431039425	11809798	2.74

¹2016 was the first full year in which the specific International Classification of Diseases 10 (ICD-10) code for Wilson disease (WD) was used as a claim label in the Clarivate clearinghouse. Because two successive claims with an ICD-10 code for WD are required for case identification, it is possible that the number of incident cases in 2016 was underestimated.

²As there is a lag time before all deaths are uploaded into the clearinghouse from death registries, the number of deaths documented for 2021 will be underestimated.