[The importance of patient reported outcome measures in Pompe disease]

In recent decades it has become increasingly important to involve patients in their diagnostic and treatment process to improve treatment outcomes and optimize compliance. By their involvement, patients can become active participants in therapeutic developments and their observations can be utilized in determining the unmet needs and priorities in clinical research. This is especially true in rare diseases such as Pompe disease. Pompe disease is a genetically determined lysosomal storage disease featuring severe limb-girdle and axial muscle weakness accompanied with respiratory insufficiency, in which enzyme replacement therapy (ERT) now has been available for 15 years.

In our present study, patient reported outcome measures (PROMs) for individuals affected with Pompe disease were developed which included questionnaires assessing general quality of life (EuroQoL, EQ-5D, SF36), daily activities and motor performance (Fatigue Severity Score, R-PAct-Scale, Rotterdam and Bartel disability scale). Data were collected for three subsequent years. The PROM questionnaires were a good complement to the physician-recorded condition assessment, and on certain aspects only PROMs provided information (e.g. fatigue in excess of patients' objective muscle weakness; deteriorating social activities despite stagnant physical abilities; significant individual differences in certain domains). The psychological effects of disease burden were also reflected in PROMs.

In addition to medical examination and certain endpoints monitored by physicians, patient perspectives need to be taken into account when assessing the effectiveness of new, innovative treatments. With involvement of patients, information can be obtained that might remain uncovered during regular medical visits, although it is essential in determining the directions and priorities of clinical research.

For all orphan medicines we emphasize to include patients in a compulsory manner to obtain general and disease-specific multidimensional outcome measures and use them as a quality indicator to monitor treatment effectiveness.