Perceived Fatigue and Physiological Fatigue in Spinal Muscular Atrophy (SMA): Are They Related? (P7.117)

Abstract

OBJECTIVE: To assess the relationship of perceived fatigue to physiologic fatigue, function, and quality of life in SMA. BACKGROUND: Fatigue is a common subjective complaint in SMA. Physiologic fatigue is well described in ambulatory SMA patients but perceived fatigue has not been systematically evaluated. Perceived fatigue and physiologic fatigue are not only different but potentially independent of each other. Understanding this relationship has been a key objective for clinical research, but has proven challenging for most disorders. METHODS: Thirty-two patients with SMA Type 3 (78.1%) and Type 2 (21.9%) ranging from 5 to 49 years were recruited from an on-going natural history study. Perceived and physiologic fatigue, function, and quality of life were assessed using standardized questionnaires and assessments. Associations between perceived fatigue and other outcomes were analyzed using Pearson correlation coefficients (p < .05). The effect of age, SMA Type, and ambulatory status on fatigue was determined using ANOVA. RESULTS: All SMA patients reported perceived fatigue (Fatigue Severity Scale=42.43 and PedsQL™ Multidimensional Fatigue Scale=72.41%). Perceived fatigue was not associated with function or quality of life in SMA patients, or with physiologic fatigue in ambulatory patients. Quality of life (Short-form 36) in adults was positively associated with the six-minute walk test (R=0.719, p=0.029). Age, SMA type, or ambulatory status did not influence perceived fatigue. CONCLUSIONS: Perceived fatigue can be quantified in children and adults with SMA. Interestingly, perceived fatigue is not related to physiologic fatigue or function in SMA, suggesting that cognitive, homeostatic, or psychologic factors may more likely be linked as co-morbid factors. For clinical trials designed to target perceived fatigue in SMA, these patient-reported assessments should be included. Quality of life is associated with function in adults with SMA. For clinical trials designed to improve function in adults, quality of life assessments may help determine clinically meaningful benefit.

Disclosure: Dr. Dunaway has nothing to disclose. Dr. Montes has received personal compensation for activities with Isis Pharmeceuticals as a consultant. Dr. Kramer has nothing to disclose. Dr. Podwika has nothing to disclose. Dr. Rao has nothing to disclose. Dr. De Vivo has received personal compensation for activities with Isis Pharmaceuticals and Ultragenyx Pharmaceuticals.