Systemic lupus erythematosus (SLE)
— or lupus, as it's more commonly known —
is far less deadly than it used to be, according to
a new Canadian study published in the August edition
of Arthritis and Rheumatism. But one of its deadliest
complications — cardiovascular disease — is
still killing many more lupus patients than it should.
While the risk of death from kidney
disease and infections has been reduced to approximately
one-fifth its level from the 1970s, the danger of cardiovascular
(CV)-related mortality seems to have actually risen
slightly. "The reasons for that are not at all clear,"
said study author Dr Sasha Bernatsky.
HEART
OF THE MATTER
Dr Bernatsky and her team from McGill University studied
over three decades of data on the largest cohort of
SLE patients ever surveyed: nearly 10,000 from seven
countries. Though the results were mostly positive,
she was surprised by the findings relating to cardiovascular
mortality. She suggested that prednisone — a corticosteroid
commonly prescribed to lupus patients — could be
contributing to hypertension. And, given that lupus
often causes persistent illness, patients aren't likely
to be very active, leading to high cholesterol, obesity
and atherosclerosis.
The association between lupus and
heart disease isn't new. A Cornell University study
published in the NEJM in 2003 showed that lupus
patients under 40 had a 140% higher risk of atherosclerosis
compared to healthy patients with similar demographic
and medical factors — and that number rose to a
staggering 480% for lupus patients over 40 years old.
MAKING
PROGRESS
Lupus is a systemic autoimmune rheumatic disease. Researchers
are still unable to pinpoint what causes it and there
is no known cure. Patients with SLE — by far the
most common variety of lupus — may suffer from
debilitating fatigue, joint problems, damaged organs
and tissues, and a host of other problems throughout
the body. But infections and kidney disease are the
most important complications associated with the disease.
And luckily, doctors are getting better at treating
both.
"Specialists are likely more aware
now of the need to aggressively treat the overactive
immune system," explained Dr Bernatsky, "and this may
be leading to fewer deaths in SLE due to renal disease
and related conditions." And, she added, it's possible
that advances in recognition and treatment, along with
more effective management of potentially harmful immunosuppressant
and anti-inflammatory drugs, have led to fewer SLE patients
suffering from serious infections.
"I think it's logical," said Dr
Ross Petty, a pediatric rheumatologist and lupus expert
from the University of British Columbia. "Infections
are now treated more rigorously and kidney disease is
treated earlier on."
CANADIANS
AT RISK
The number of people affected by lupus is still unknown,
but Dr Bernatsky cites a growing body of research that
puts the prevalence at about one in 2,000, or about
15,000 Canadians.
Interestingly, she also found that
Canadian lupus patients, who accounted for more than
a quarter of the group, suffered a slightly higher risk
of death than their peers from any of the six other
countries surveyed, including the US and England. Hesitant
to draw any conclusions from this finding, Dr Bernatsky
suggests different demographic and clinical factors,
including the racial composition of the study's subjects,
may account for the disparity.
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