Adult patients with late-onset Pompe disease (PD) receiving enzyme replacement therapy (ERT) perceive improvements in physical aspects of their quality of life (QoL) and their ability to carry out activities of daily living when their pulmonary function increases according to a study published in the Journal of Inherited Metabolic Disease.
Using Bayesian multivariate mixed-effects models adjusted for time, sex, age, and disease duration at the start of ERT, a theoretical 1% increase in forced vital capacity in the upright position (FVCup) would be expected to result in a .14 point increase in the physical component summary score (PCS) of the Medical Outcome Study 36-Item Short-Form Health Survey (SF-36).
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A theoretical increase of 1% in FVCup would also be expected to cause a .41 point increase on the Rasch-Built Pompe-Specific Activity (R-PACT) scale, a measurement of activities of daily living.
R-PACT and PCS were also found to be nonlinearly associated with time when FVCup was held constant. These scores generally increased during the first 5 years following the initiation of ERT but then decreased over time. FVCup was found to remain roughly stable during the first 5 years of ERT but decrease after that.
Because of the negative association of factors with time, the positive effects from the improvement in FVCup can be overshadowed by the decreases over time.
“This study has shown that there is a correlation between FVCup and the reports of patients [patient-reported outcome measures (PROMs)], suggesting that we might be able to deduce a minimum level of change that is relevant for a patient (MCID) that could be used to interpret the results of trials or in clinical evaluation,” the authors wrote.
Post-hoc analysis on data from 2 prospective observational cohort studies was performed and included data from 101 Dutch adult patients with late-onset PD. R-PACT data was available for 94 of the patients and PCS was available for 100 patients. The median age at the start of ERT was 50 years while the median age of symptom onset was 33 years. The median follow-up time in the study was 9.3 years.
Reference
Lika A, Andrinopoulou ER, van der Beek NAME, et al. Association between changes in pulmonary function and in patient reported outcomes during enzyme therapy of adult patients with late-onset Pompe disease. J Inherit Metab Dis. Published online March 26, 2023. doi:10.1002/jimd.12606
