LONG-TERM AND SHORT-TERM OUTCOME OF MULTIPLE-SCLEROSIS - A 3-YEAR FOLLOW-UP-STUDY

Background: The anticipated rate of short-term worsening of disability scores is the basis of power estimations in clinical trials of progre ssive multiple sclerosis (MS). While the clinician is most concerned i n modifying the long-term outcome (eg, time to reach the Expanded Disa bility Status Scale [EDSS] 6), the end points studied in clinical tria ls are those describing short-term outcome (eg, worsening of EDSS scor es over 1 to 3 years). However, short-term outcome of MS may not be co rrelated with long-term outcome. Objectives: To validate previously pu blished models predicting time to EDSS 6. To establish predictors of s hort-term outcome of MS. Setting: The Ottawa, Ontario, Regional Multip le Sclerosis Clinic. Patients: Two hundred fifty-nine patients were fo llowed up prospectively by a single neurologist. Main Outcome Measures : Actuarial analysis of time to reach EDSS 6 and change in EDSS scores over a follow-up period of 1 to 3 years. Results: The long-term outco me in the Ottawa population was more favorable than published data fro m London, Ontario. Predictions of time to EDSS 6 were not strongly cor related with the degree of short-term worsening over the follow-up per iod. Parameters associated with a higher probability of short-term wor sening were proximity of the baseline EDSS score to 4.5 and duration o f MS less than 20 years. Conclusion: Baseline EDSS and duration of MS must be considered in the design of clinical trials of progressive MS.