Outcome measures in multiple sclerosis

Abstract

The physicians'perspective. The clinical assessment of outcome in patients with multiple sclerosis (MS) is problematic because the disease can affect different parts of the central nervous system (CNS). The Kurtzke expanded disability status scale (EDSS), the most universally employed scoring system used in MS studies, has shortcomings since some dimensions of impairment and disability such as manual dexterity, neuropsychological functions and fatigue are not measured. In 1997 the National MS Society of the United States Clinical Outcomes Assessment Task Force issued recommendations on the use of composite outcomes to determine the effects of treatment in MS clinical trials. Nonetheless, EDSS scores continued to be the major outcome measure in all clinical trials reported to show clinical effects of Interferon beta and glatiramer acetate. The patients' pers/fective. The need for measures of health-related quality of life ( HRQOL) that include physical, mental and social health and therefore express the patients' rather than the physicians' assessments of disability and MS is being increasingly recognized. Both generic HRQOL measures, which are applicable to a wide range of illnesses, and MS-targeted instruments which are more sensitive to changes specific to MS, arc coming into more general use. However, the lack of a satisfactory definition of HRQOL and the absence of consensus on which of the many instruments should be used remains a problem. The few interferon trials that assess HRQOL as an outcome measure failed to detect a beneficial effect. The economic perspective. In the face of limited resources, decision-makers in the health care systems are forced to demand cost-benefit analyses of therapeutic interventions in MS. Methods to estimate cost-effectiveness and cost-benefit ratios are in the process of being developed. The quality-adjusted life year (QALY). which allows tor comparisons of results across different diseases, has become a common outcome measure for MS treatment. Several studies indicate that the cost per QALY gained is very high in interferon therapy compared to therapeutic interventions in other chronic diseases. ©Springer-Verlag 2001.