THE IMPACT OF DIFFERENT STAGES OF MULTIPLE SCLEROSIS ON HEALTH UTILITIES- A SYSTEMATIC REVIEW OF THE LITERATURE

OBJECTIVES Multiple Sclerosis (MS) causes neurological disability of varying severity. Disability in MS is measured by the Kurtzke Expanded Disability Status Scale (EDSS), a clinician-based neurological impairment rating scale (scale from 1 to 10, with 10 being death). For most patients, MS will progress from an episodic disorder (relapsing-remitting MS) to a more progressive state (secondary progressive MS). We conducted a systematic review of the literature to determine how health related quality of life, as measured by health utilities, changes with the increasing neurological disability associated with different stages of MS. METHODS Employing pre-defined search terms and inclusion/exclusion criteria, systematic searches were conducted in MEDLINE, EMBASE, PsycINFO, Health Economic Evaluation Database (HEED), NHS Economic Evaluations Database (NHS/EED), and the UK National Institute for Health and Clinical Excellence (NICE) website. All databases were searched from 1 January 1993 to 5 August 2008. Data extraction was validated by an independent reviewer. RESULTS We identified 16 studies reporting health utilities associated with health states of MS. EQ-5D was the most common preference elicitation instrument. Health utilities ranged from 0.80 to 0.89 for patients with an EDSS score of 1, from 0.49 to 0.71 for patients with an EDSS score of 3, from 0.39 to 0.54 for patients with an EDSS score of 6.5, and from -0.19 to 0.08 for patients with an EDSS score of 9 with some patients valuing their health states as worse than death. CONCLUSIONS MS has a significant impact on quality of life. Utilities decrease significantly with increasing neurological disability. Without taking into consideration EDSS score, there appears to be no difference in health utilities between RRMS and SPMS patients and the variation in health utilities appears to be mainly explained by the severity of the disability. Utilities also decreased significantly during relapse phases.