Disability and survival of multiple sclerosis in Saskatoon, Saskatchewan

Abstract

Background: A population-based prevalent group of 150 clinical definite patients ascertained on 1 January 1977, in Saskatoon, Saskatchewan, was followed for 30 years.

Objectives: To outline the clinical characteristics, determine the levels of disability at 15, 25, 35, 40, and 45 years after onset, to estimate the survival after onset and life expectancy.

Methods: Clinical records were maintained, and the cohort reviewed each decade for 30 years. The disability levels according to the Kurtzke Extended Disability Status Scale were recorded and survival times were estimated. SPSS and Kaplan-Meier methods were used for analysis.

Results: On prevalence day, 1 January 1977, there were 48 (32%) men and 102 (68%) women, with an average age of onset of 32.2 +/- 10 years and 28.4 +/- 8.6 years. The average duration of disease was 15.7 years. On 1 January 2007, 39 (26%) patients were living, 105 (70%) deceased, and 6 (4%) were missing The disability levels recorded in 1977 and 2007, at 15 and 45 years after onset, were mild (EDSS < or = 2.5), 33.3% and 8.0%; moderate (EDSS3-5.5), 17.3% and 2.7%; severe (EDSS6-7.5), 6.6% and 4.7%; maximum (EDSS8-9.5), 22.7% and 10.7%. The median survival time after onset was 33 (95% CI: 27.3-38.6) years for men and 38 (95% CI: 34.1-41.9) years for women. The median duration of life was 68.9 years for men and 69.5 years for women, and a decreased life expectancy of 7.7 and 12.8 years.

Conclusions: Multiple sclerosis is a progressive neurological disorder and long-term survival is associated with moderate to severe disability and decreased life expectancy.