An observational study of a large United Kingdom primary care
database showed that switching patients from Pfizer's Lipitor(R)
(atorvastatin calcium) Tablets to simvastatin was associated with a 30
percent increase in the relative risk of major cardiovascular events,
including heart attacks, strokes and certain types of heart surgeries,
or death compared to patients who remained on Lipitor therapy.
This analysis was presented today at the European Society of
Cardiology Congress 2007 and is also in press at The British Journal
of Cardiology.
The data, which included records from October 1997 to June 2005,
were generated from a retrospective analysis of a medical database of
anonymous patient records entered by general practitioners in the
United Kingdom known as The Health Improvement Network (THIN). The
analysis included 11,520 patients (2,511 patients who had taken
Lipitor for six months or more and were switched to simvastatin vs.
9,009 patients who were taking Lipitor for six months or more and then
remained on Lipitor therapy). Reasons for switching were not available
from the database. Since patients were not randomly assigned to each
group, the two treatment groups were matched based on certain risk
factors and statistical adjustments were made to address any residual
imbalances. As with all observational studies, the findings should be
regarded as hypothesis generating.
"Today, many health care payors including governments and managed
care companies are encouraging patients who are well-established on
one therapy to switch to a different statin therapy," said Dr. Michael
Berelowitz, senior vice president of Pfizer's global medical division.
"This study raises concerns about those policies. It suggests the
potential for poorer cardiovascular outcomes associated with switching
patients from established Lipitor therapy to simvastatin."
A secondary analysis of the same data showed that patients who
were switched from Lipitor to simvastatin were more than twice as
likely to discontinue their treatment compared to those who remained
on Lipitor therapy (20.5 percent versus 7.62 percent, p(less
than)0.001). The reasons for discontinuation were not available from
the database, though disruption in treatment has been associated with
poor adherence in previous studies of statins and other medications.
"The results of this analysis complement the large body of
evidence from multiple clinical trials demonstrating the
cardiovascular benefits of Lipitor," said Dr. Berelowitz.
"Observational studies help the medical community better appreciate
what is really happening in doctors' offices, and are commonly used by
healthcare payors to set medical practice guidelines. This analysis
highlights the need to carefully consider individual patient
circumstances and cardiovascular risk because indiscriminate switching
may adversely affect some patients."
Additional Study Information
The primary endpoint was time to a first major cardiovascular
event, defined as heart attack, stroke, or coronary revascularization
(a type of heart surgery), or all-cause death. There was a
statistically significant 30 percent increase in the relative risk of
the primary endpoint (p=0.03).
-- The individual components making up the primary endpoint were
analyzed as secondary endpoints. Compared with patients who
did not switch therapy, switching was associated with the
following:
-0-
*T
-- Significant 43 percent increase in the relative risk of
major cardiovascular events (p=0.008)
-- No difference in all-cause death (p=0.369)
*T
-- The two treatment groups were matched based on the following:
gender, history of heart attack, diabetes, time since last
statin exposure and general practitioner treatment center.
-- The following statistical adjustments were made to address any
residual imbalances: age, gender, prior statin exposure, time
since last statin exposure, diabetes, history of heart attack,
and baseline cholesterol levels.
-- Relative risk is the ratio of the risk of major cardiovascular
events or death occurring in the group who switched from
Lipitor to simvastatin versus the risk in the group who
remained on Lipitor.
About Lipitor
Lipitor is the only statin with all the following criteria most
important for many physicians, patients and payors: significant and
proven cardiovascular event reductions, impressive average LDL
lowering of 39 percent to 60 percent, and a proven safety profile
across a broad range of patients.
Lipitor is the most prescribed cholesterol-lowering therapy in the
world, with nearly 139 million patient-years of experience. It is
supported by an extensive clinical trial program involving more than
400 ongoing and completed trials with more than 80,000 patients. There
have been more than ten cardiovascular outcomes trials with more then
50,000 patients.
Important Safety Information
Lipitor is a prescription medication. It is used in patients with
multiple risk factors for heart disease such as family history, high
blood pressure, age, low HDL ("good" cholesterol) or smoking to reduce
the risk of heart attack, stroke, certain kinds of heart surgery, and
chest pain. When diet and exercise alone are not enough, Lipitor is
used along with a low-fat diet and exercise to lower cholesterol.
Lipitor is also used in patients with type 2 diabetes and at least
one other risk factor for heart disease such as high blood pressure,
smoking or complications of diabetes, including eye disease and
protein in urine, to reduce the risk of heart attack and stroke.
Lipitor is not for everyone. It is not for those with liver
problems. And it is not for women who are nursing, pregnant or may
become pregnant.
Patients taking Lipitor should tell their doctors if they feel any
new muscle pain or weakness. This could be a sign of rare but serious
muscle side effects. Patients should tell their doctors about all
medications they take. This may help avoid serious drug interactions.
Doctors should do blood tests to check liver function before and
during treatment and may adjust the dose. The most common side effects
are gas, constipation, stomach pain and heartburn. They tend to be
mild and often go away.
For additional product information, visit www.Lipitor.com.
