Factors Associated to Quality of Life (QoL) in Patients Affected by Amyotrophic Lateral Sclerosis (ALS) and Duchenne Muscular Dystrophy (DMD)

Background: ALS and DMD are neuromuscular disorders leading to physical disability, respiratory failure, and altered quality of life. These diseases are often associated with an altered sleep quality and autonomic dysfunction, even under noninvasive ventilation (NIV). In this study, relationships of quality of life with quality of sleep and autonomic disturbances, as well as with age and spirometric values in ALS and DMD were investigated. Methods: Forty patients with ALS (age 64.9± 8.7 years, forced vital capacity [FVC] 56.4 ±27.5% predicted) and 29 patients with DMD (age 29.3±10.1 years, FVC 22.2 ± 16.9 % predicted) were evaluated. Individualized neuromuscular quality of life questionnaire (INQoL), Pittsburgh sleep quality index (PSQI) and Compass 31 questionnaire were used to assess quality of life, subjective sleep quality and autonomic function, respectively. Results: Worse mean scores were obtained from all questionnaires in the ALS patients (INQoL: 63.9±18.1 vs 42.8±21.1, p<0.0001; PSQI: 10.5±5.2 vs 6.4±3.0, p=0.0004; Compass 31: 20.5±14.2 vs. 12.9±10.1, p=0.01 [ALS vs. DMD, respectively]). INQoL was not significantly correlated either to the PSQI or to the Compass 31 total scores in any group, although in the DMD patients it showed a borderline correlation with the PSQI (r=0.36, p=0.052). Among the INQoL domains, pain was correlated to sleep disturbances (r=0.36 p=0.02) and age (r=0.41, p=0.008) in the ALS patients, and to worse sleep efficiency (r=0.57 p=0.001) and bladder dysfunction in the DMD patients (r=0.37 p=0.04). Besides, in the ALS group independence was significantly correlated with FVC (r=-0.44 p= 0.009), and fatigue was significantly correlated with sleep disturbances (r=0.34 p=0.02) and gastrointestinal problems (r=0.34 p=0.02). In addition, in the DMD group muscle weakness was correlated with sleep efficiency (r=0.46 p=0.01) and FVC (r=-0.44 p= 0.009), and locking with age (r=0.47 p= 0.01) Conclusions: Quality of life components are differently associated with quality of sleep, autonomic function, age and lung function in ALS and DMD. That suggests that alteration of quality of life may recognise different pathogenic mechanisms in the two diseases.