Disability profile of MS did not change over 10 years in a population-based prevalence cohort.

OBJECTIVE: To assess whether the level of multiple sclerosis (MS) -related disability in the Olmsted County population has changed over a decade, and to evaluate how the rate of initial progression to moderate disability impacts further disability. METHODS: The Minimal Record of Disability (MRD) measured impairment, disability, and handicap for the 2000 (n = 201) prevalence cohort. The authors compared these results with the 1991 (n = 162) cohort; 115 patients were in both cohorts. The authors assessed retrospectively intervals at which Expanded Disability Status Scale (EDSS) scores of 3 (moderate disability), 6 (cane), and 8 (wheelchair) were reached. RESULTS: The distribution of the 2000 EDSS and MRD scores were not significantly different from the 1991 distribution. The median time from MS diagnosis, for the entire cohort, to EDSS scores of 3 and 6 was 17 and 24 years, respectively. At 20 years after onset, only 25% of those with relapsing-remitting MS had EDSS scores > or =3. The median time from diagnosis to EDSS score of 6 for the secondary and primary progressive groups was 10 and 3 years, respectively. Rate of progression from onset or diagnosis to EDSS score of 3 did not affect the rate of further disease progression. However, once an EDSS score of 3 was reached, progression of disability was more likely, and rate of progression increased. CONCLUSIONS: The distribution of multiple sclerosis disability in the Olmsted community has remained stable for 10 years. Progression of disability for patients with relapsing-remitting multiple sclerosis or secondary progressive multiple sclerosis may be more favorable than reported previously. Once a clinical threshold of disability is reached, rate of progression increased.

Change in MS-related disability in a population-based cohort: a 10-year follow-up study.

OBJECTIVE: S: To study the change in disability over 10 years in individual patients constituting the 1991 Olmsted County, MN, multiple sclerosis (MS) prevalence cohort. METHODS: The authors reassessed this 1991 cohort in 2001. The authors determined the Expanded Disability Status Scale scores (EDSS) for each patient still alive, and within the year prior to death for those who died. The authors analyzed determinants of potential prognostic significance on change in disability. RESULTS: Follow-up information was available for 161 of 162 patients in the 1991 cohort. Only 15% had received immunomodulatory therapy. The mean change in EDSS for the entire cohort over 10 years was 1 point and 20% worsened by >or=2 points. For patients with EDSS <3 in 1991 (n = 66), 83% were ambulatory without a cane 10 years later. For patients with EDSS of 3 through 5 in 1991 (n = 33), 51% required a cane to ambulate (48%) or worse (3%). For patients with EDSS 6 to 7 in 1991 (n = 39), 51% required a wheelchair or worse in 2001. Gait impairment at onset, progressive disease, or longer duration of disease were associated with more worsening of disability (p < 0.002). The 10-year survival was decreased compared with the Minnesota white population for both men and women. CONCLUSIONS: Although survival was reduced and 30% of patients progressed to needing a cane or wheelchair or worse over the 10-year follow-up period, most remained stable or minimally progressed. Patients within the EDSS 3.0 through 5.0 range are at moderate risk of developing important gait limitations over the 10-year period. The authors did not identify factors strongly predictive of worsening disability in this study.

Incidence and prevalence of multiple sclerosis in Olmsted County, Minnesota, 1985-2000.

BACKGROUND: Epidemiologic data for multiple sclerosis (MS) in Olmsted County, MN, have been recorded for almost 100 years and have indicated that the increasing prevalence rate was likely due in part to an increasing incidence rate. METHODS: All cases of MS diagnosed from 1985 to 2000 were identified using the centralized diagnostic index at the Mayo Clinic and the Rochester Epidemiology Program Project, a shared database of all medical practitioners in the county. Patients were required to have established residency at least 1 year prior to diagnosis of MS. Results were also age- and sex-adjusted to control for shifts in the population structure. RESULTS: The raw prevalence of MS was determined to be 177 per 100,000 on December 1, 2000, and the raw incidence rate was 7.5 per 100,000 person-years at risk from 1985 to 2000. CONCLUSIONS: After age and sex adjustment to a common population, these prevalence and incidence rates of MS appear to have been stable rather than increasing over the past 20 years.