Associations between onset age and disability in multiple sclerosis patients studied using MSSS and a progression model.
BACKGROUND
While many factors have been examined, male gender and older age at multiple sclerosis onset are among few variables consistently associated with increased disability. Interestingly, the association between onset age and disability may not be linear with some data suggesting a faster rate of accumulation of disability in patients aged more than 30 years at onset.


OBJECTIVE
Explore the relationship between onset age and disability.


METHODS
We studied 500 MS patients grouped by cut-offs in onset age. Disability was assessed using Multiple Sclerosis Severity Scale (MSSS) and, a model based on time to reach an Extended Disability Severity Score (EDSS) (progression model). Data were analyzed using linear and logistic regression.


RESULTS
The association between disability (assessed by both MSSS and the progression model) and onset age was different in patients whose MS onset occurred after an age band of 30-35 years. Before this age range, changing age was not associated with changes in disability while during and after this age range, disability was increased.


CONCLUSIONS
We found a significant change in the relationship between disability and onset age after about 31 years supporting the idea that while onset age does not define a sharp cut-off, it can help define subgroups of patients with differing rates of accumulation of disability.
Keele Multiple Sclerosis Research Group, Department of Neurology, University Hospital of North Staffordshire, Stoke-on-Trent, ST4 7LN Staffordshire, England, United Kingdom; Department of Biochemistry, Good Hope Hospital, Heart of England Foundation Trust, Sutton Coldfield B75 7RR, England, United Kingdom.
Sudarshan
S
Ramachandran
Keele Multiple Sclerosis Research Group, Department of Neurology, University Hospital of North Staffordshire, Stoke-on-Trent, ST4 7LN Staffordshire, England, United Kingdom; Institute for Science and Technology in Medicine, Keele University Medical School, Hartshill Campus, Stoke-on-Trent ST4 7QB, England, United Kingdom.
Richard C
RC
Strange
Keele Multiple Sclerosis Research Group, Department of Neurology, University Hospital of North Staffordshire, Stoke-on-Trent, ST4 7LN Staffordshire, England, United Kingdom; Institute for Science and Technology in Medicine, Keele University Medical School, Hartshill Campus, Stoke-on-Trent ST4 7QB, England, United Kingdom.
Peter W
PW
Jones
Keele Multiple Sclerosis Research Group, Department of Neurology, University Hospital of North Staffordshire, Stoke-on-Trent, ST4 7LN Staffordshire, England, United Kingdom; Institute for Science and Technology in Medicine, Keele University Medical School, Hartshill Campus, Stoke-on-Trent ST4 7QB, England, United Kingdom.
Seema
S
Kalra
Keele Multiple Sclerosis Research Group, Department of Neurology, University Hospital of North Staffordshire, Stoke-on-Trent, ST4 7LN Staffordshire, England, United Kingdom; Institute for Science and Technology in Medicine, Keele University Medical School, Hartshill Campus, Stoke-on-Trent ST4 7QB, England, United Kingdom.
Devaki
D
Nayak
Keele Multiple Sclerosis Research Group, Department of Neurology, University Hospital of North Staffordshire, Stoke-on-Trent, ST4 7LN Staffordshire, England, United Kingdom; Institute for Science and Technology in Medicine, Keele University Medical School, Hartshill Campus, Stoke-on-Trent ST4 7QB, England, United Kingdom. Electronic address: c.p.hawkins@pmed.keele.ac.uk.
Clive P
CP
Hawkins
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D017668:Age of Onset; D003198:Computer Simulation; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D009103:Multiple Sclerosis / Q000175:diagnosis* / Q000401:mortality*; D011379:Prognosis; D015203:Reproducibility of Results; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D017678:Sex Distribution; D013223:Statistics as Topic; D015996:Survival Rate; D013548:Sweden / Q000453:epidemiology; D055815:Young Adult
Disability evaluation; EDSS; Multiple sclerosis; Progression model