Becker muscular dystrophy (BMD) is a rare hereditary neuromuscular disease, caused by a genetic defect in the Duchenne Muscular Dystrophy (DMD) gene. We studied the natural history of respiratory function and its affecting factors in 23 adult BMD patients. These important data are needed for (future) clinical trials in BMD but are largely lacking. Patients had a median age of 51 years (28-78y) and median follow-up duration of 14 years (2-25y). We analysed 190 pulmonary function measurements with a median interval of one year (1-17y) and measured a 1.00% decline of Forced Vital Capacity percent predicted (FVC%pred) per year (p = 0.004). Loss of ambulation significantly increased the annual rate of FVC decline and was dependent of patient's body mass index (BMI; p = 0.015), with increases in BMI correlating with an even more rapid deterioration of FVC. A decline in Medical Research Council (MRC) sum score was significantly correlated with a decline in FVC (p = 0.003). We conclude that adult BMD patients experience a significant but mild respiratory decline. However, this decline is significantly more rapid and clinically relevant after loss of ambulation, which warrants a more vigilant follow-up of respiratory function in this subgroup.

中文翻译：

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成人贝克肌营养不良症患者呼吸功能下降：一项纵向研究

贝克肌营养不良症（BMD）是一种罕见的遗传性神经肌肉疾病，由杜氏肌营养不良症（DMD）基因的遗传缺陷引起。我们研究了 23 名成年 BMD 患者的呼吸功能自然史及其影响因素。这些重要数据是（未来）BMD 临床试验所需要的，但在很大程度上缺乏。患者的中位年龄为 51 岁（28-78 岁），中位随访时间为 14 年（2-25 岁）。我们分析了 190 次肺功能测量值，中位间隔为一年 (1-17 年)，并测量了强迫肺活量预测百分比 (FVC%pred) 每年下降 1.00% (p = 0.004)。不能走动显着增加了 FVC 的年下降率，并且取决于患者的体重指数 (BMI; p = 0.015)，BMI 的增加与 FVC 的更快恶化相关。医学研究委员会 (MRC) 总分的下降与 FVC 的下降显着相关 (p = 0.003)。我们得出结论，成年 BMD 患者经历了显着但轻微的呼吸下降。然而，这种下降在失去行走能力后明显更快且具有临床意义，因此需要对该亚组的呼吸功能进行更加警惕的随访。