Role of disease severity, illness perceptions, and mood on quality of life in muscle disease.

INTRODUCTION: The aim of this study was to describe the effect of muscle disease upon QoL and to explore the influence of disease severity, mood, and illness perception on the QoL of these patients. METHODS: Validated questionnaires assessing QoL (Individualized Neuromuscular QoL and SF-36), disease severity (Health Assessment Questionnaire), mood (Hospital Anxiety and Depression Scale) and illness perception (Illness Perception Questionnaire) were sent to adults with muscle disease. RESULTS: We received 302 responses (return rate 75%). QoL was reduced, particularly for "physical" domains, but "psychological" domains were also affected. Disease severity was the main determinant for the "physical" domains of QoL, but mood and illness perception played a part. Conversely, mood and illness perception were the main determinants for the "psychological" domains of QoL. CONCLUSIONS: Because mood and illness perception explain significant variance in QoL in muscle disease, there is scope for devising psychosocial interventions that may improve QoL for those with muscle disease.