Rapid disease course in African Americans with multiple sclerosis.
OBJECTIVE
To investigate utility of a Multiple Sclerosis Severity Scale (MSSS)-based classification system for comparing African American (AA) and white American (WA) multiple sclerosis (MS) subpopulations in the New York State Multiple Sclerosis Consortium (NYSMSC) database. MSSS is a frequency-rank algorithm relating MS disability to disease duration in a large, untreated reference population. Design/


METHODS
Distributions of patients in 6 MSSS-based severity grades were calculated for AA and WA registrants.


RESULTS
There were 419 AA and 5,809 WA patients in the NYSMSC, who had EDSS recorded during years 1-30 since symptom onset. Median EDSS was not different in AA and WA (3.5 vs 3.0, p = 0.60), whereas median MSSS in AA was higher than in WA (6.0 vs 4.8, p = 0.001). AA patients were overrepresented in the 2 most severe grades (41.5% vs 29.3% for WA) and underrepresented in the 2 lowest grades (23.4% vs 35.4%; p < 0.001). In multivariable analysis (ordered logistic and median regression), MSSS for AA remained significantly higher than in WA after adjusting for age, gender, disease duration, disease type distribution, and treatment with disease-modifying therapies.


CONCLUSIONS
The 6-tiered MSSS grading system is a powerful tool for comparing rate of disease progression in subpopulations of interest. MSSS-based analysis demonstrates that African ancestry is a risk factor for a more rapidly disabling disease course.
Kister
I
I
Department of Neurology, NYU School of Medicine, Multiple Sclerosis Care Center, New York, NY 10003-3804, USA. ilya.kister@gmail.com
Chamot
E
E
Bacon
J H
JH
Niewczyk
P M
PM
De Guzman
R A
RA
Apatoff
B
B
Coyle
P
P
Goodman
A D
AD
Gottesman
M
M
Granger
C
C
Jubelt
B
B
Krupp
L
L
Lenihan
M
M
Lublin
F
F
Mihai
C
C
Miller
A
A
Munschauer
F E
FE
Perel
A B
AB
Teter
B E
BE
Weinstock-Guttman
B
B
Zivadinov
R
R
Herbert
J
J
D000328:Adult; D001741:Black or African American / Q000208:ethnology*; D017668:Age of Onset; D004185:Disability Evaluation; D018450:Disease Progression; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000453:epidemiology* / Q000208:ethnology* / Q000503:physiopathology; D015999:Multivariate Analysis; D009518:New York / Q000453:epidemiology; D011379:Prognosis; D012720:Severity of Illness Index