Association of Muscle Strength and Walking Performance in Adult Patients With Pompe Disease

Abstract

BackgroundThe loss of the ability to walk is among the most prominent signs of Pompe disease. The associations with muscle strength have not been described.ObjectiveThe objective of this study was to estimate the associations of walking performance with muscle strength in 4 specific lower extremity muscle groups along with other factors in adult patients with Pompe disease.DesignThis was a single-center, cross-sectional study.MethodsMuscle strength (hand-held dynamometry of hip flexion and abduction and knee extension and flexion) and walking performance (unable to walk, able with aids, walking without aids but with a waddling gait, or walking without aids and with a normal gait) were assessed in 107 patients at their first visit. Relationships between walking performance and muscle strength were studied through multivariate analyses and regression modeling. Age, sex, body mass index (BMI), disease duration, and use of ventilator support were taken into account as potential confounders. The results were transformed into a nomogram to allow the probability of a patient having a certain level of walking performance to be calculated based on the values of the independent variables.ResultsWalking performance declined significantly with decreasing muscle strength of hip flexion and abduction and knee extension and flexion. The final selected model, including strength of the hip abductor and knee extensor, BMI, age, sex, and use of ventilation, predicted 66% of the cases accurately.LimitationsThese results are based on cross-sectional data and do not predict future changes.ConclusionsIn adult people with Pompe disease, walking performance can be explained by muscle strength, BMI, age, sex, and ventilation use. The proposed model gives insight into how an individual is expected to walk based on his or her risk factors and serves as a starting point to unraveling factors associated with walking performance and ultimately to developing a prognostic model.

Are there common walking gait characteristics in patients diagnosed with late-onset Pompe disease?

“…There is some evidence to suggest that females are likely to have better walking performance compared to males (i.e. a higher proportion of females walk with a more typical gait) (Favejee et al, 2018) however, this was crosssectional study and therefore would be difficult to draw predictive conclusions. To our knowledge there is limited evidence exploring differences in strength and walking characteristics between males and females who are diagnosed with LOPD.…”

“…Future research should explore the lumbar spine posture and motion during walking. indicates exercise tolerance (Chetta et al, 2006;Gibbons, Fruchter, Sloan, & Levy, 2001) and has shown to reduce with the progression of late-onset Pompe disease in association with reduced strength and respiratory capacity (Favejee et al, 2018;Schüller et al, 2012;Wokke et al, 2008). Furthermore, inclusion criteria for LOPD patients in this study required individuals to be able to walk unaided for 50 m. However, McIntosh et al (2015) recruited individuals who were able to walk at least 10 m with or without a walking aid, with 50% of participants using a walking aid during their study.…”

“…Whilst currently, 200 individuals are estimated to be diagnosed with LOPD in the UK ("Pompe Disease (GSD2)," 2019), only six adult metabolic services are available in the UK. Approximately 39 -47% of individuals with LOPD use walking aids (Favejee et al, 2018;Van Der Beek et al, 2012) therefore the remaining individuals who walk independently are likely to be significantly lower than the 200 estimated individuals.…”

“…The authors also concluded that these finding correlated with the corresponding muscle MRI scans. Hip abductor weakness(Favejee et al, 2018) and hip flexor weakness(Van Den Berg et al, 2015) has also been reported. Such muscle atrophy is likely to reduce an individual's ability to stabilise the pelvis and trunk, resulting in a 'waddling' or myopathic gait.…”

“…Progressive weakness and reduced respiratory function limit the distance an individual can walk and their ability to perform daily activities (Case & Kishnani, 2006;Favejee et al, 2018;Wokke et al, 2008). As the disease progresses individuals become more reliant on medical devices such as walking aids and ventilatory support devices (Hagemans et al, 2005;van der Ploeg & Reuser, 2008;Wokke et al, 2008).…”