Fatigue in Multiple Sclerosis and Its Relationship to Clinical Status

Multiple Sclerosis (MS) is the leading cause of permanent disability in young adults. Iran is considered a high risk zone for MS and its incidence has risen in recent years. Fatigue is a common and disabling symptom in MS and its timely diagnosis and treatment can markedly improve the quality of life in the affected patients. There is a considerable heterogeneity in the results of most reported studies on the prevalence of fatigue in MS and its contributing factors. Most of them did not pay attention specifically to the role of clinical parameters in the prevalence and severity of fatigue. To determine the relative frequency of fatigue in MS patients and the link between fatigue and clinical status In this cross-sectional study, 167 patients with definite relapsing MS, according to McDonald 2005 criteria, filled the questionnaires containing items on demographic data and main clinical symptoms of MS (visual, sensory, motor, balance, and sphincteric) and Fatigue Severity Scale (FSS). Then, they were examined to determine Expanded Disability Status Scale (EDSS) score. In 167 patients, 43 (25.7%) were male and 124 (74.3%) were female. Mean age, fatigue severity according to FSS and EDSS score were 32.34, 39.49, and 1.96, respectively. Relative frequency of fatigue was 60.5%. In univariate analysis, a significalnt correlation was found between fatigue severity and age, EDSS score, pyramidal involvement, imbalance, visual and sphincter involvement, however, in multivariate analysis a significant correlation was only found with EDSS score and age. Fatigue is a frequent symptom in the patients with MS. It is a heterogenous symptom with numerous etiologies; however, the clinical status of the patients can greatly help predict its occurance. It seems that EDSS score is an efficient and sufficient clinical indicator of fatigue severity.