Characterizing Physical Function and Activity in Adults With X-Linked Hypophosphatemia

According to a report, published in Osteoporosis International, there is a lack of literature on the physical function and activity in adult patients with X-linked hypophosphatemia (XLH). As such, G. Orlando and colleagues examined muscle strength and power, functional capacity, mobility, and physical activity level, and the relationships between them in adults with XLH. They found that this population had a “marked deficit in lower limb muscle power and a reduced functional capacity, with a high incidence of impaired mobility and inactivity.”

The participants were recruited as part of the UK-based prospective cohort study, RUDY. Patients completed the International Physical Activity Questionnaire (IPAQ), a clinical visit, and a physical examination assessing handgrip strength, jump power (mechanography), six-minute walk test (6MWT), and short physical performance battery (SPPB).

A total of 26 adults with XLH were recruited into the trial. Compared to individuals with normative values, patients with XLH had 54.4% and 38.6% lower jump power and 6MWT distances, respectively (p <0.0001). Additionally, the authors noted that “handgrip strength values were similar to expected values,” however, they also found that “deficits in muscle power were more pronounced than those reported at 6MWT (p <0.0001).” Finally, univariate analysis showed an association between the total physical activity and muscle power variables (r = 0.545; p = 0.019).

Orlando and the study’s contributors ultimately concluded that, for adults with XLH, low physical activity and impaired mobility were common features, and also that “deficits in lower limbs muscle power and functional capacity contribute to the loss of physical function in adults with XLH.”