Age of loss of walking ability in patients with Duchenne muscular dystrophy: A marker for the elective use of mechanical ventilation?

Abstract

Introduction: In adolescence of Duchenne muscular dystrophy (DMD) comes the cardioventilatory restrictive impairment (hypoventilation, sleep breathind disorder and respiratory effort), marked by the loss of ambulation. At that time, the institution may be required ventilatory support (VS). VS improve lung function, reducing need for tracheostomy and increasing quality of life in DMD. Public Program (Ventilar-VP) in John Paul II Child Hospital/Hospitalar Foundation of Minas Gerais State (JPIICH/HFMGS) assist DMD patients.

Objective: To evaluate loss of ambulation and the need to VS in patients with DMD in VP/JPIICH/HFMGS.

Patients and methods: Cohort study, between 2002-2010 in VP. Group A: 16 (25.8) VS users and group B: 46 (74.2) nonusers of VS. Likelihood of VS was estimated by survival analysis of Kaplan-Meier.

Results: Medians for the entire sample (years): last visit: 15.6 (6.4 to 30.2), monitored by the VP: 4.5 (0 to 6.5). Median age (years) loss of ambulation: A 8.1 (5-13), B 10 (6.7 to 15) (p=0.05). Majority in A lost early ambulation. Significant difference between the two groups (p=0.05). Survival curve of cumulative probability of VS: age <11 years: no patient needed VS, 16 years: 20%, 23 years: 50%, and 26 years: 100%. Statistically significant difference in the cumulative probability (p<0.001) in need of SV among patients with loss of ambulation before 10 years (group C) and with loss of ambulation after that age (group D). 15 years of age, 12% of patients in C required SV. 100% needed to SV in C, in D only after 23 years.

Conclusion: Age of loss of ambulation at age 10 is a marker for estimating the need of early VS in patients with DMD.