Health-Related Quality of Life and Perception of Care of Mucopolysaccharidosis Type I - Hurler Syndrome Patients after Successful Hematopoietic Cell Transplantation: A Parents' Perspective

Background: Mucopolysaccharidosis type I - Hurler syndrome (MPS IH) is a lysosomal storage disease characterized by multi-system morbidity and death in early childhood. Hematopoietic cell transplantation (HCT) results in long-term survival, although with significant residual disease burden. The effect of this disease burden on the health-related quality of life of MPS IH patients after HCT is however still unknown. Furthermore, little is known about the perception of care of transplanted MPS IH patients.

Methods: 63 alive and engrafted MPS IH patients, transplanted at one of the seven participating centers within Europe were included in the study. The functional and psychosocial health were evaluated using two validated questionnaires: the Child Health Questionnaire (CHQ) and Pediatric Outcomes Data Collection Instrument (PODCI). Subscale and summary scores were compared to normative samples to derive z-scores and standard deviations (SD). The influence of various patient, donor, transplantation as well as disease-specific predictors was evaluated using univariate and multivariate linear regression analysis. Correlation analysis between the functional and psychosocial scores of the CHQ and PODCI was performed using Spearman's rank correlation. The perception of care was evaluated by a third validated questionnaire: the Measure of Processes of Care (MPOC) questionnaire.

Results: The functional health of transplanted MPS IH patients was significantly diminished compared with normative data; mean physical summary z-score -2.5 (SD 1.5), mean global functioning z-score -3.6 (SD 2.5) (figure 1 and 2). The psychosocial health appeared to be comparable or only slightly reduced compared to normative data; mean psychosocial summary z-score -0.1 (SD 1.3) (figure 1). A higher obtained IDUA enzyme level after HCT predicted for superior functional health, supporting the use of only non-carrier donors and approaches to achieve full-donor chimerism. There was a modest to strong correlation between the functional and psychosocial domain scores of the CHQ and PODCI. Furthermore, the parents were overall satisfied with the care received. The multidisciplinary follow-up setting with experienced specialists in all participating centers might have positively contributed to this high level of satisfaction.

Conclusion: The functional health of transplanted MPS IH patients was significantly more affected than the psychosocial health compared to their healthy peers. Assessing the functional as well as the psychosocial health can play an important role in the evaluation of outcomes in MPS IH patients receiving HCT as well as new therapeutic approaches.

Figure 1. Results of the Child Health Questionnaire (CHQ)

Figure 2. Results of the Pediatric Outcomes Data Collection Instrument (PODCI)