Multiple Sclerosis Journal - October 2017 - 1556

Multiple Sclerosis Journal 23(11)
For the NYU cohort, for whom insurance information
was available, we ran an ANCOVA controlling for
age, gender, and insurance type in order to account for
socioeconomic status. We found that insurance type
(F = 93.8, p < 0.0001) had a direct impact on P-MSSS,
but that race was still significant predictor of P-MSSS
after controlling for age, gender, and insurance
(p < 0.0001). Age- and gender-adjusted P-MSSS for
AA and HA were both significantly higher than that of
CA (p < 0.0001 for each), but there was no significant
difference between HA and AA (p = 0.17).
Discussion
In our outpatient MS clinic cohort, HA had younger
age of onset and a more severe disease course compared to CA and similar age of onset and disease
severity as compared to AA (though there was a
trend for higher severity in AA relative to HA). The
differences between the three ethnic groups could
not be ascribed to socioeconomic factors alone,
inasmuch as higher disease severity in HA relative
to CA as well as of AA versus CA was maintained
even after controlling for insurance type.
Nonetheless, insurance type was a statistically significant factor in P-MSSS and this highlights potential healthcare disparities between the ethnic groups
that could have some impact on disease severity.
Further study on the complex relationship between
insurance type and such factors as the distribution
of disease-modifying therapies or amount of ancillary care prescribed is merited.
Our finding of more aggressive disease course in HA
compared to CA is at variance with an analysis of
MSBase registry that did not detect a difference
between MSSS among patients enrolled in Latin
America versus Europe and North America. The discrepancy between the two studies could be due to the
fact that we are comparing patients of different ethnicities within two NY area outpatient centers, rather
than between centers in different countries, which
may be subject to regional enrollment biases.10
Alternatively, our HA population with MS in the
New York metropolitan area may have an intrinsically more aggressive form of MS compared to
Hispanics residing in Latin America. Or our cohort
may have an over-representation of Hispanics from
particular Latin American countries that are associated with more aggressive disease. Unfortunately,
factors such as country of ancestry and age of migration to the United States, all of which may affect disease severity13, were not included in our analysis as
this information was not routinely recorded for our
patients.
1556

Our finding of higher disease severity in AA versus
CA corroborates a previous study with a different
patient population that utilized the MSSS.5 In this
study, there was a 1.3-point increase in P-MSSS in AA
versus CA women in our cohort, while in NY State MS
Consortium, AA had 1.5-point higher MSSS than CA.5
The observed differences in disease severity among
the three ethnic groups in our study may be due to
environmental factors, such as diet and its effect on
the microbiome, comorbidities such as obesity,
amount of exercise, genetic factors, or socioeconomic and cultural factors that were not controlled
by insurance type. Potential differences in disease
pathophysiology among ethnic groups merit further
study and may have implications for treatment and
management of MS patients. Our study also illustrates the utility of using P-MSSS, a readily obtainable measure of disease severity that, unlike
EDSS-based MSSS, does not impose additional time
demands on the busy clinician.
Declaration of Conflicting Interests
The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: R.E.V. has
received research support from EMD Serono; A.O.A.
has served as speaker for Biogen Idec and Genzyme;
T.B. reports no disclosures; I.K. is on the scientific
advisory board for Biogen Idec and Genentech, and
received research support from Biogen Idec, Serono,
Novartis, Guthy-Jackson Charitable Foundation, and
National Multiple Sclerosis Society.
Funding
The author(s) declared receipt of the following financial support for the research, authorship, and/or publication of this article: REV received salary support
through a Founda-tion Supporting the Consortium of
MS Centers/EMD Serono Donald W. Paty ClinicianScientist Development Fellowship Award.

References
1. Kaufman MD, Johnson SK, Moyer D, et al. Multiple
sclerosis: Severity and progression rate in African
Americans compared with whites. Am J Phys Med
Rehabil 2003; 82(8): 582-590.
2. Marrie RA, Cutter G, Tyry T, et al. Does multiple
sclerosis-associated disability differ between races?
Neurology 2006; 66(8): 1235-1240.
3. Naismith RT, Trinkaus K and Cross AH. Phenotype
and prognosis in African-Americans with multiple
sclerosis: A retrospective chart review. Mult Scler
2006; 12(6): 775-781.

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Table of Contents for the Digital Edition of Multiple Sclerosis Journal - October 2017