Fatigue: an important feature of late-onset Pompe disease

OBJECTIVE: To investigate the prevalence and severity of fatigue in adult patients with Pompe disease. METHODS: The Fatigue Severity Scale (FSS) was assessed in an international population of 225 adults with Pompe disease, a metabolic disorder presenting as a slowly progressive proximal myopathy. The FSS scores were compared to those of healthy controls and the relationship between the level of fatigue and other patient characteristics was investigated. RESULTS: The mean age of the participants was 47 (SD 13) years and the mean disease duration 11 (SD 8) years. 43% used a wheelchair and 46% had respiratory support, 29% needed both. 67% of the participants had a FSS score ≥5, indicating severe fatigue. The mean FSS score was 5.2 (SD 1.5), which was significantly higher than that of healthy controls (p < 0.001). Fatigue was not related to age, sex or disease duration. Patients who used a wheelchair or respiratory support were on average more fatigued than those who did not (p = 0.01). However, of the patients who did not use these aids, 59% also had a FSS score ≥5. FSS scores were highest among patients who reported a high frequency of sleep disorders, but patients who never experienced sleep difficulties were also fatigued (mean FSS score = 4.8). CONCLUSION: Fatigue is highly prevalent among both mildly and severely affected adult patients with Pompe disease. The FSS appears a useful tool in assessing fatigue in Pompe disease.