Minimal clinically important differences in six-minute walking distance in late-onset Pompe disease

• Published in: Orphanet journal of rare diseases Vol. 19; no. 1; p. 154
• Main Authors: Claeys, Kristl G, Kushlaf, Hani, Raza, Syed, Hummel, Noemi, Shohet, Simon, Keyzor, Ian, Kopiec, Agnieszka, Graham, Ryan, Fox, Brian, Schoser, Benedikt
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 11.04.2024; BioMed Central; BMC
• Subjects: 6MWD; Body mass index; Care and treatment; Causes of; Complications and side effects; Disease; Disease severity; Exercise tests; Glycogenosis; Late-onset Pompe disease; MCID; Medical prognosis; Methods; Minimal clinically important difference; Musculoskeletal diseases; Neuromuscular diseases; Outcome and process assessment (Health Care); Patient outcomes; Patients; Six-minute walk distance; Walking; United States; Disease severity; Six-minute walk distance; MCID; 6MWD; Late-onset Pompe disease; Minimal clinically important difference
• ISSN: 1750-1172; 1750-1172
• DOI: 10.1186/s13023-024-03156-3

The minimal clinically important difference (MCID) is the smallest change in outcome that physicians or patients would consider meaningful and is relevant when evaluating disease progression or the efficacy of interventions. Studies of patients with late-onset Pompe disease (LOPD) have used the 6-min walk distance (6MWD) as an endpoint to assess motor function. However, an MCID for 6MWD (% predicted and meters) has yet to be established in LOPD. The objective of the study was to derive 6MWD MCID (% predicted and meters) with different analysis methods and for subgroups of different disease severity for LOPD. Data from the PROPEL trial were used to calculate 6MWD MCID in the overall PROPEL population and subgroups of baseline severity as assessed by walking distance and body mass index (BMI), using anchor- and distribution-based approaches. The 6MWD MCIDs varied widely, depending on the method and subgroup, ranging from 2.27%-8.11% predicted for the overall LOPD population (23.7 m-57.2 m). For patients with baseline 6MWD < 150 m, MCIDs ranged from -0.74%-3.37% (-2.1 m-11.3 m). MCIDs increased with distance walked at baseline until a plateau was reached. For BMI subgroups, the MCIDs were generally lowest in obese patients. Our analysis shows that MCID depends on the chosen method and disease severity. The findings suggest that applying a single MCID to all patients can be misleading; consequently, a range of possible MCIDs should be considered. This may also be highly relevant for other neuromuscular diseases. This study provides a range of 6MWD MCIDs for LOPD, with lower MCIDs for more severe patients.