Annals of Neurology
Volume 51, Issue 4, 2002. Pages: 475-480
Maria Trojano, MD 1 *, Maria Liguori, MD 1, Giovanni Bosco Zimatore, MD 1, Roberto Bugarini, Dstat 2, Carlo Avolio, MD 3, Damiano Paolicelli, MD 1, Fabrizio Giuliani, MD 1, Francesca De Robertis, MD 1, Maria Giovanna Marrosu, MD 4, Paolo Livrea, MD 1
(1) Department of Neurological and Psychiatric Sciences, University of Bari, Bari
(2) Laboratory of Epidemiology and Biostatistics, Istituto Superiore Sanità, Rome
(3) Department of Neurology, University of Foggia, Foggia
(4) Multiple Sclerosis Center, Department of Neuroscience, University of Cagliari, Cagliari, Italy
Funded by: Fondazione Italiana Sclerosi Multipla (M.T.), Istituto Superiore di Sanità (M.T.); MIUR Piano Biomedicina (P.L.)
There is evidence that the clinical course of multiple sclerosis is age related.
The present study evaluated the relationship between age and rate of disability progression in a large hospital-based cohort of definite cases of multiple sclerosis (n= 1,463).
Patients were followed every 6 to 12 months for a total period of observation of 11,387.8 person-years. Expanded Disability Status Scale scores increased significantly with increasing current age and longer duration of disease (p=0.007).
Median times to reach Expanded Disability Status Scale scores of 4.0 and 6.0, assessed using an extended Kaplan-Meier method with age as a categorical time-varying covariate, were significantly longer among patients aged 20 to 35 years compared with patients aged 36 to 50 and 51 to 65 years (p < 0.0001). Significant associations were observed between mean Expanded Disability Status Scale scores and age at disease onset, current age, and the interaction of age at disease onset and current age (p < 0.001).
Current age had a greater effect (59% of variability in the model) on disease severity than did age at disease onset.
Furthermore, a multiplicative effect on Expanded Disability Status Scale score was observed for age at disease onset and current age combined, indicating a faster rate of disease progression in older patients.
In conclusion, the results of the current study demonstrate
the impact of age on rate of disability progression in multiple sclerosis
and suggest that an age-adjusted progression index may be a more relevant
criterion for defining differences between multiple sclerosis groups.
Copyright © 2002 Wiley-Liss, Inc.