[Impact of fatigue in multiple sclerosis: study of a population-based series in Valladolid].

Introduction: Fatigue is one of the commonest findings in multiple sclerosis (MS) although it has scarcely been investigated as an independent symptom.
Objective: To evaluate the effect of fatigue in a population based series of patients with MS and to analyze its relation to other clinical variables.
Methods: A descriptive, transverse study based on a geographically defined population. Fatigue was measured using the Krupp scale in 48 patients with definite clinical MS. We analyzed the relation between the degree of fatigue and sex, age of onset, age at the time of the study, type of evolution, index of progression of disability, duration of illness and degree of impairment according to the Expanded Disability Status Scale (EDSS) and neurological functional systems.
Results: 64.6% of the patients had a significant degree of fatigue. Of these, 90% considered fatigue to be one of the three most disabling symptoms of their illness. There was no difference between men and women in their perception of fatigue. The patients with progressive illness, of greater age and those with higher EDSS scores had more fatigue. This aspect was not affected by age of onset, duration of illness nor index of progression.
Conclusions: Fatigue should be evaluated as an independent symptom of MS. Evaluation using specific scales may contribute to better understanding of the physiopathology and investigation of more effective treatment.