Patients Who Switched from Established Lipitor Therapy to Simvastatin Experienced a Significant 30 Percent Increase in Relative Risk of Cardiovascular Events or Death, New Observational Study Shows
VIENNA, Austria--(BUSINESS WIRE)--An observational study of a large United Kingdom primary care database showed that switching patients from Pfizerâ€™s LipitorÂ® (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.
â€œToday, 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,â€ said Dr. Michael Berelowitz, senior vice president of Pfizerâ€™s global medical division. â€œThis study raises concerns about those policies. It suggests the potential for poorer cardiovascular outcomes associated with switching patients from established Lipitor therapy to simvastatin.â€
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<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.
â€œThe results of this analysis complement the large body of evidence from multiple clinical trials demonstrating the cardiovascular benefits of Lipitor,â€ said Dr. Berelowitz. â€œObservational studies help the medical community better appreciate what is really happening in doctorsâ€™ 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.â€
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:
-- Significant 43 percent increase in the relative risk of
major cardiovascular events (p=0.008)
-- No difference in all-cause death (p=0.369)
* 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.
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 (â€œgoodâ€ 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.