Lung function changes with initiation of noninvasive ventilation in childhood duchenne muscular dystrophy

Abstract

Introduction/Aim. The use of non-invasive ventilation (NIV) support in children has increased rapidly over the past decade. The aim of this study was to describe and analyse lung function (LF) changes with initiation of NIV in children with Duchenne Muscular Dystrophy (DMD), and assess for differences between Steroid Users and Steroid Naïve subjects. Method. A retrospective clinical audit of children with DMD who were initiated on NIV in the past ten years was conducted. Serial LF data was collected for individuals throughout adolescence, including the period before and following NIV initiation. Results. Twenty-nine males with DMD started NIV during the ten year study period. Nine subjects were using steroids, with a median age of commencement of 6 years (IQR 2.5, range 4-8). The median age that NIV was initiated was 14.66 years (IQR 2.35, 10.47-17.96) with no significant differences in initiation seen been Steroid Users vs. Steroid Naïve groups. Lung function is better (FVC z-score-3.26 vs-5.41, P < 0.02) and the rate of decline is slower (FVC z-score-0.58 vs-0.68, P < 0.001) in Steroid Users, compared to those who are Steroid Naïve. The median rate of decline in FVC z-score prior to NIV initiation was-0.72 z-score pa (95% CI-0.79,-0.64, SE 0.04, P < 0.01) and following NIV initiation it was-0.46 z-scores pa (95% CI-0.54,-0.38, SE 0.04, P < 0.01). This reduction in rate of decline following NIV initiation was significantly different, P < 0.001. The rate of decline in FVC is significantly reduced following NIV initiation in the steroid Naïve group, but increased in the Steroid User group and this reaches significance for z-scores (P < 0.001) and % predicted values (P < 0.001) Conclusion. The rates of decline in FVC are higher in boys with DMD prior to NIV than they are following NIV initiation. Long-term steroid use did not affect the age of NIV initiation in this cohort. However, Steroid Naïve patients have lower LF, and an increased rate of decline in LF prior to NIV initiation, which slows following NIV initiation.L6269392862019-04-02 <br />