People who later develop multiple sclerosis (MS) have increased health
care use during the five years before their
first demyelinating events, compared with
healthy individuals, according to research
published online ahead of print April 20
in Lancet Neurology. This finding suggests
the existence of a measurable MS prodrome, said Helen Tremlett, PhD, Professor of Neurology at the University of
British Columbia in Vancouver, Canada.
A Large Case–Control Analysis
Previous studies have provided evidence for an MS prodrome that occurs years before a demyelinating event or
the onset of clinical symptoms. Many of these studies,
however, have been limited by a retrospective design or
by the absence of a control group.
To analyze the question further, Dr. Tremlett and
colleagues examined data from linked health administrative and clinical databases in the Canadian provinces
of British Columbia, Saskatchewan, Manitoba, and Nova
Scotia, which were chosen for their geographic diversity
and comprehensive data. The researchers created a health
administrative cohort, which was based on administrative data, and an MS clinic-derived cohort, which used
administrative and clinical data. The study’s primary outcome was all-cause use of health care during each of the
five years before the health administrative index date (ie,
the first demyelinating disease-related claim) or clinical
index date (ie, the date of MS symptom onset).
Health Care Use Increased in Prodromal MS
The health administrative cohort included 14,428
people with MS and 72,059 matched controls. In all,
10,525 (73%) of the patients with MS were women, and
their mean age at the health administrative index date
was 43. Compared with controls, annual
health care use increased steadily between
five years and one year before the first de-
myelinating disease claim in these patients.
The mean number of hospital admis-
sions was 26% higher in people with MS
than in controls in the fifth year before the
index date, and 78% higher in the year
before the index date. The mean number
of physician claims was 24% higher in
people with MS than in controls in the
fifth year before the index date, and 88%
higher in people with MS than in controls in the year
before the index date. Also, the mean number of pre-
scribed drug classes was 23% higher in people with MS
than in matched controls in the fifth year before the
index date, and 49% higher in people with MS than in
controls in the year before the index date.
The MS clinic cohort included 3,202 people with MS
and 16,006 matched controls. In all, 2,368 (74%) of
people with MS were women, and the mean age at the
clinical index date was approximately 37. Compared
with the health administrative cohort, this cohort had
similar patterns for physician claims and prescriptions,
although the differences in use in each of the five years
mostly did not reach statistical significance.
“To gain a better insight into the MS prodrome, the
complex reasons for increased health care use will need
to be established, for example, through access of additional administrative data such as the specific diagnostic codes related to a hospital admission or physician
visit, or the therapeutic drug class for a prescription,”
Dr. Tremlett concluded. NR
Wijnands JMA, Kingwell E, Zhu F, et al. Health-care use before a first demyelinating event suggestive of a multiple sclerosis prodrome: a matched cohort
study. Lancet Neurol. 2017 Apr 20 [Epub ahead of print].
MS May Have a Measurable Prodrome
Patients who develop MS have increased physician visits and hospital admissions
before symptom onset, compared with healthy controls.
Helen Tremlett, PhD