Burden of Illness in Acid Sphingomyelinase Deficiency: A Retrospective Chart Review of 100 Patients

Abstract

Acid sphingomyelinase deficiency (ASMD) is a rare, progressive, and often fatal lysosomal storage disease caused by the deficiency of the enzyme acid sphingomyelinase (ASM) resulting in accumulation of sphingomyelin in target tissues. Little is known regarding predictors of disease-related morbidity, healthcare use, and lifestyle impact in adults with chronic disease. A multinational retrospective study collected data on the burden of illness and healthcare resource use for 100 patients across the clinical spectrum of ASMD, including those with rapidly progressive infantile neurovisceral disease (n = 13) and those with the more slowly progressive chronic neurovisceral (n = 6) and chronic visceral (n = 81) disease. Growth was subnormal throughout childhood for all patients with chronic neurovisceral disease and for 50% of patients with chronic visceral disease. Developmental delay, regression, and/or learning disabilities were reported in 40% of patients with chronic neurovisceral ASMD and 21% of patients with chronic visceral ASMD. Outpatient therapy or home healthcare was required for 50% of patients with chronic neurovisceral disease and 12% of patients with chronic visceral disease. Disease-related disability for patients with chronic disease resulted in need for home schooling for 16% of patients and compromised work ability for 22% of patients. Grade school was the highest level of education for 22% of patients older than 13 years of age.

Keywords: Acid sphingomyelinase deficiency; Burden of illness; Disease manifestations; Lysosomal storage disorder; Natural history; Niemann-Pick disease types A and B.

Fig. 1

Z-scores for height/length and weight over time. Z-scores are plotted for the indicated time points across all three ASMD phenotypes. Number of patients (n) and number and percent with subnormal growth (defined as <5th percentile of the reference population based on NCHS/WHO international reference data for weight and height of children) at each time point are indicated below the graphs

Fig. 2

Burden of chronic ASMD on patient lifestyle. (a) Highest grade levels attained by patients with chronic ASMD. (b) Impact of disability on ability to work in patients with chronic visceral ASMD