Dont Stop Taking Your Statin!

Summarized by Robert W. Griffith, MD
October 25, 2005

Introduction

Taking statins lowers the chances of having a heart attack, stroke, or angina, even if your lipid levels are normal. But what happens to people who stop taking their statin medication, for one reason or another? This question has been researched by a group of Canadian scientists, who've published their findings in the journal Pharmacotherapy. Here's a summary of their results.

What they did

Information was obtained from the Saskatchewan Government databases, which carry data on prescription drug use, as well as other pertinent facts. Patients were included in the study if they got a new prescription for a statin between 1994 and 2001, within one year of their first cardiovascular event (heart attack, unstable angina¹, coronary angioplasty, or bypass surgery). They were excluded from the analysis if they had, or developed, a serious non-cardiovascular medical condition, or if their first cardiovascular event occurred within 10 months of starting a statin. Registered patients were followed until the first occurrence of either a cardiovascular event, or a stroke, or death. Statins are normally dispensed in one-month allotments.

Adherence to taking their statin medication was done by examining the "fill frequency" of prescriptions i.e. the number of prescriptions filled divided by the months of observation. Switching from one statin to another didn't alter this estimation of adherence. To analyze a possible effect of discontinuing statins on the outcome, the patients were allocated to two groups (called cohorts) - those with 60% or less adherence, called the nonadherent group, and those with 80% or better adherence, called the adherent group. (Those with 60% to 80% were not allocated, or analyzed further.)

What they found

There were 1501 patients enrolled; however, 280 were eliminated as they had less than 10 months follow-up. The average of the remaining1221 subjects was 58; 77% were men; 26% had diabetes; and the average period of follow-up was just over 3 years. There were 661 patients (54%) in the adherent group and 395 (32% in the nonadherent group.

The two groups were similar in nearly all respects, except that the adherent group received slightly more drugs, including ACE inhibitors and beta-blockers, and had more angioplasties, compared to the non-adherent group. Adherence to taking prescribed ACE inhibitors and/or beta blockers was significantly less in the nonadherent group.

• Heart attacks (myocardial infarction, or MI) were half as frequent in the adherent as in the nonadherent patients; they occurred in 2.1% (14 cases) of the adherent group, and in 4.1% (16 cases) of the nonadherent group. These results were statistically significant i.e. they would not have occurred by chance alone.

In patients under 65, both heart attacks and unstable angina were reduced in those patients who adhered to taking their statins; for heart attacks, the difference was 1.5% vs. 4.1% for nonadherent subjects.

In the 300-odd patients over 65, statin adherence was not linked to any significant reductions in cardiovascular events.

What the results mean

It seems clear that not taking a prescribed statin drug regularly (i.e. less than 60% of the time) exposes someone to twice the risk of having a heart attack, and, in those under 65, to an increased risk of developing unstable angina as well. It's likely that if there had been more people in the study, other benefits of sticking to taking statins would have emerged, such as a decrease in death rate.

We've emphasized the benefits of statin drugs in these pages before, especially for diabetic patients. However, one must be aware that all drugs - including statins -have side effects. Some patients may experience severe side effects with statins, although this is very rare. So, take heed of what the side effects are (they're usually listed on the paper the pharmacist gives you with your medication), keep alert, and visit your doctor if you develop any of the described symptoms. Otherwise, take your statin regularly - it's worth it!

Source

• Cardiovascular morbidity associated with nonadherence to statin therapy. BDF. Blackburn , DRT. Dobson , BJL. Blackburn , WTL. Wilson , Pharmacotherapy , 2005, vol. 25, pp. 1035--1043

Footnotes
1. Unstable angina is characterized by a change in the usual pattern of stable angina, chest pain that occurs at rest or with less and less exertion, chest pain that may be more severe and last longer, chest pain that doesn't respond as well to nitroglycerin, or the onset of angina in a person who previously did not have it.

Related Links
Should We Put Statins in the Drinking Water?
Statins Work Even When the Cholesterol Isn't Raised
Double the Effectiveness of Your Statin?

Please take a moment to give us your comments. For questions about Health matters you may check our "Questions & Answers" Portal and Service.