Lung function monitoring in patients with duchenne muscular dystrophy on steroid therapy

Abstract

Background: Duchenne muscular dystrophy (DMD) is a sex-linked inherited muscle disease characterized by a progressive loss in muscle strength and respiratory muscle involvement. After 12 years of age, lung function declines at a rate of 6 % to 10.7 % per year in patients with DMD. Steroid therapy has been proposed to delay the loss of motor function and also the respiratory involvement.

Method: In 21 patients with DMD aged between seven and 16 years, the forced vital capacity (FVC) and the forced expiratory volume in one second (FEV1) were evaluated at three different times during a period of two years.

Results: We observed in this period of evaluation the maintenance of the FVC and the FEV1 in this group of patients independently of chronological age, age at onset of steroid therapy, and walking capacity.

Conclusion: The steroid therapy has the potential to stabilize or delay the loss of lung function in DMD patients even if they are non-ambulant or older than 10 years, and in those in whom the medication was started after 7 years of age.

Figure 1

Individual values of Forced Vital Capacity (FVC) were expressed in % of the predicted value. After the Evaluation I (baseline), patients were followed yearly (evaluations II and III). Patients were divided in 2 groups according their age (7–10 years and 11–16 years).

Figure 2

Individual values of Forced Expiratory Volume in 1 sec (FEV₁) were expressed in % of the predicted value. After the Evaluation I (baseline), patients were followed yearly (evaluations II and III). Patients were divided in 2 groups according their age (7–10 years and 11–16 years).