http://www.cnn.com/2016/09/08/health/study-explores-pros-and-cons-of-statins/index.html
The thought that comes to mind when you hear the word "statin" may depend on your age. Below the age of 40 and you may not have come across them, but for everyone else, these drugs can be something they love, or equally as often, loathe.
Statins
are a class of drugs used to reduce low-density lipoprotein, LDL
cholesterol, within the body. They prescribed to people with high LDL
cholesterol, when levels are above two to three milliliters
of cholesterol per liter of blood. These individuals are at risk of
cardiovascular diseases such as heart disease, stroke and heart attack.
The drug works by inhibiting the enzyme involved in the body's ability to produce this form of cholesterol.
They are a common prescription among the 73.5 million adults
with high LDL cholesterol in the United States. Among the US
population, 26% of adults were using statins in 2012, according to the Centers for Disease Control and Prevention. Globally, raised cholesterol levels are estimated to cause 2.6 million deaths each year, according to the World Health Organization.
But
statins have a reputation that precedes them, with people often worried
about taking them, or going as far as declining them, without always
knowing the evidence behind their decision. There have been reports of
the drug causing side effects that include an increased risk of
hemorrhagic stroke, muscle pain and weakness and diabetes, causing
acceptance of the drug to be split.
A study
published Thursday conducted a major review of the available evidence
on the safety and efficacy of statin therapy, to provide the evidence
needed to help people make their decision. It was decidedly in their
favor.
"Statins have had a huge impact on reducing cardiovascular events," said Rory Collins, BHF professor of medicine and epidemiology at the Nuffield Department of Population Health, part of the University of Oxford.
"There are many misleading claims about statins ... [but] people tend to underestimate the benefits," he said.
How beneficial are they?
After
reviewing all the available evidence on the harms and benefits of
statins, the study had a few key findings, including one based on the
daily use of 40 mg of the drug atorvastatin for five years and by 10,000
patients. Among these 10,000 patients, the study predicted the drug
would prevent 1,000 people having major cardiovascular events (heart
attacks, strokes and coronary artery
bypasses) who had pre-existing heart conditions. The same regimen would
also prevent 500 cardiovascular events in people who are at increased
risk, due to diabetes or hypertension for example, but haven't had a
heart condition.
"You avoid 1,000 or 500 people having a heart attack, stroke or similar," said Collins.
When
put into perspective in the United Kingdom, Collins added that among
the 4 million people with previous heart events, and 2 million people at
increased risk in the country, 80,000 heart attacks would be prevented
each year, while 600 might develop myopathy (a rare condition involving
muscle pain, tenderness or weakness that can be severely disabling and
sometimes fatal).
A
further analysis found that for each 1 mmol/L reduction in LDL
cholesterol made using statin therapy, the risk of coronary deaths and
heart attacks, strokes and coronary bypass procedures is reduced by
approximately 25% for each year the drugs are taken after the first
year.
But one concern among some
experts, and opponents, is the eventual use of statins to treat people
who have high cholesterol, but have not had previous cardiovascular
issues and do not have diabetes of hypertension, meaning more people
take them than needed. Fewer studies have shown that statins reduce the
risk of cardiovascular diseases in healthy people with high cholesterol.
What about the harms?
The
study also reviewed the occurrence of side effects, such as muscle
pain, hemorrhagic stroke and myopathy, to identify whether the
controversies around the use of statins are warranted.
Among
the 10,000 patients, the researchers found the drug would cause five
cases of myopathy, as well as five to 10 hemorrhagic strokes -- caused
by weak blood vessels bursting -- 50 to 100 new cases of diabetes, and
up to 100 cases of symptomatic adverse events, such as muscle pain.
"The
reality is that the harms associated with statins are tiny," said
Collins, who emphasized that the harms should still be acknowledged and
informed to patients, but along with their likelihood. "There have been
problems of people believing the harms are common," he said.
Other
studies have also stated that statins may increase the likelihood of a
range of other conditions, including memory loss, cataracts, kidney
injury, liver disease, sleep disturbance, aggression, suicidal
behavioral, erectile disjunction and neuropathy, which the researchers
stress would be extremely rare and that evidence for them is not
sufficient.
"The best available scientific evidence tells us that statins are effective, safe drugs," said Liam Smeeth,
head of the Department of Non-Communicable Disease Epidemiology.
"[They] have a crucial role in helping prevent cardiovascular disease,
the leading cause of morbidity and mortality worldwide."
Other
experts not involved in the study agree. "A series of high-quality
clinical trials conducted over more than a quarter of a century and
originating in multiple populations have consistently demonstrated
reductions in cardiovascular death, and major complications in patients
taking statins," said Robin Choudhury, professor of Cardiovascular
Medicine, University of Oxford.
Statins
are, however, typically prescribed to those at greater risk of
developing heart disease and recommendations often made before this
stage are lifestyle based: a healthier diet, regular exercise and
reducing the amount of alcohol you drink and cigarettes you may smoke.
Other drug options are also available, including the drug Repatha, approved last year, which is prescribed on a more limited basis.
Understanding what's out there
"There
are a lot of high-risk patients who are not taking statins," said
Collins, who wants people to better understand the information available
to them regarding these drugs.
The
researchers highlight in the paper that studies based on observations
within a population do not produce reliable evidence about the effects
of drug treatments for common health conditions, such as heart disease,
and cannot attribute the cause of any benefits or side-effects
specifically to a drug.
They
instead highlight the credibility of randomized controlled trials, which
can directly link any benefits, or harms, to the drug being trialed.
For such trials, the evidence on statins was seen to be overwhelmingly
in favor of the treatment.
"[This
study] is an unusually comprehensive document that explains not only the
evidence derived from these studies but the rationale and relative
merits for evaluating drugs," added Choudhury, who was not involved in
the study. "Wrong decisions based on incomplete, misleading, or
misguided interpretation of the data and the consequent confusion leads
to the squandering of actual benefits to real patients."
"This
is really serious stuff ... and anything you can do to prevent them
really matters," said Smeeth. "The problem we have with statins is that
misleading claims that are not supported by scientific evidence have
really come to the fore ... and they're demonstrably wrong."
Collins
added that the team wanted to make people know which evidence they
should trust. "People should make informed choices," he said. "I hope
this helps recreate some of the balance."
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