Ali Mohajer, PhD, Qral Group, discusses the age-stratified burden of post-allogeneic hematopoietic stem cell transplantation (post-allo-HSCT) complications in Hurler syndrome (MPS IH).
MPS IH is the most severe form of mucopolysaccharidosis type I, caused by a deficiency of α-L-iduronidase, resulting in progressive accumulation of the glycosaminoglycans dermatan sulfate and heparan sulfate. It is characterized by skeletal abnormalities, cognitive impairment, heart disease, respiratory problems, enlarged liver and spleen, characteristic facial disformaties, and reduced life expectancy. Allo-HSCT is widely used to improve survival and attenuate aspects of disease progression in MPS IH.
The objective of this cross-sectional retrospective claims-based analysis was to characterize the prevalence and multisystem breadth of post-allo-HSCT complications among children and young adults with MPS IH and to describe how complication profiles vary across chronological age bands. The study used commercially available, de-identified US medical claims data spanning 1 January 2017 to 1 October 2024. Post-allo-HSCT complications were identified through ICD-10-CM diagnosis codes and mapped to 10 clinically meaningful problem categories: Orthopedic, Spinal, Motor, Cardiovascular, Auditory, Visual, Cognitive, Developmental, Endocrine/growth (auxological), and Hepatosplenomegaly.
The analysis included 299 patients and 10,268 diagnosis–category records corresponding to 932 unique ICD-10-CM diagnosis codes. Post-allo-HSCT complications were common and multisystemic. The most prevalent categories were: Orthopedic: 87.6%; Cognitive: 80.6%; Auditory: 77.3%; Cardiovascular: 76.6%; Developmental: 76.3%; and Visual: 73.2%.
Age-band stratification showed distinct patterns:
- At ages 0 to 2 (n=17), cardiovascular complications were the most prevalent category in 58.8%, followed by auditory in 41.2% and orthopedic, cognitive, developmental, and visual complications, each in 35.3%.
- At ages 3 to 7 (n = 83), orthopedic and cognitive complications were each present in 77.1%, with high prevalence of developmental in 73.5%, cardiovascular in 66.3%, auditory in 63.9%, and visual in 62.7%.
- At ages 8 to 15 (n = 126), orthopedic complications were observed in 95.2% and multiple domains were highly prevalent including auditory in 88.9%, cognitive in 88.1%, developmental in 84.9%, cardiovascular in 84.1%, and visual in 82.5%. Notably, spinal complications were frequent in this band, observed in 63.5% of patients.
- At ages 16 to 24 (n = 73), orthopedic complications occurred in 98.6% with continued high prevalence of cognitive in 82.2%, auditory in 80.8%, cardiovascular in 79.5%, and visual in 78.1%. Spinal complications remained common, occurring in 57.5% of patients.
Multisystem involvement was typical. Considering the 10 clinical complication categories, patients had a median of 7 categories. Overall, 77.3% had evidence of 5 or more clinical categories and 57.9% had 7 or more categories. Evidence of concurrent involvement across six high prevalence domains (orthopedic, cognitive, developmental, auditory, cardiovascular, and visual), were observed in 47.8% of patients.
To learn more about MPS and other rare lysosomal storage disorders, visit https://checkrare.com/diseases/lysosomal-storage-disorders/
