Health-related quality of life in multiple sclerosis: current evidence, measurement and effects of disease severity and treatment.

Health-related quality of life (HR-QOL) is an important measure of health in patients with multiple sclerosis (MS), given that MS symptoms affect many aspects of everyday living. Physicians may tend to focus on physical or cognitive changes in patients with MS because these measures involve physician- or psychologist-administered tests rather than patient self-reporting. However, a number of validated instruments are available to evaluate HR-QOL in clinical studies. Several studies have used these instruments to evaluate the effects of traditional disease-modifying therapies (DMTs), i.e. interferon-beta and glatiramer acetate on HR-QOL in patients with MS. The results of many of these studies showed that DMTs improved some aspects of patients' HR-QOL, but study design issues such as small patient numbers or lack of placebo control for comparison have made it difficult to interpret these results. Two large, randomized, placebo-controlled studies of the newest DMT, natalizumab, showed that this therapy resulted in significant improvements in HR-QOL in patients with relapsing MS. Furthermore, the effects of natalizumab on HR-QOL were apparent, regardless of disease characteristics. The natalizumab studies definitively show that HR-QOL measures can be informative in a clinical trial setting and support the position that patient-reported outcomes, including HR-QOL measures, should be included in clinical trials to more fully assess therapeutic efficacy.