Limitations of 6‐minute walk test reference values for spinal muscular atrophy

Introduction The 6‐minute walk test (6MWT) is a well‐established clinical assessment of functional endurance, validated as a measure of walking ability in spinal muscular atrophy (SMA). The current availability of disease‐modifying therapies for SMA indicates a growing need for normative reference data to compare SMA patients with healthy controls. Methods The literature was searched in two scientific databases. Studies were evaluated and selected based on adherence to American Thoracic Society guidelines for administering the 6MWT. Reference equations from the selected studies were applied to 6MWT data collected from SMA patients to calculate and compare % predicted values. Results Three pediatric and six adult studies were selected for comparison. The % predicted values using the pediatric and adult equations ranged from 47.7 ± 18.2% to 67.6 ± 26.2% and 43.0 ± 17.9% to 59.5 ± 26.2%, respectively, and were significantly different (P