DURHAM, N.C. -- While a class of cholesterol-lowering drugs known as statins are effective in reducing the chances of a second heart event for patients with coronary artery disease, a new analysis shows that only patients whose cholesterol levels are above the recommended guidelines are likely to benefit from receiving these drugs earlier than usual.
"While we know the benefits of statins in preventing subsequent heart events, few have looked at whether starting heart attack patients on the therapy earlier would have any benefit," said Duke University Medical Center cardiologist L. Kristin Newby, M.D., who published the results of her analysis today (June 19, 2002) in the Journal of the American Medical Association.
"Our analysis indicates that physicians should use caution in prescribing statins during the early phase of an acute coronary syndrome if their patients' LDL-cholesterol levels are lower than the 130 mg/dL guidelines," she continued. "Since it appears that there is a relationship between the LDL-cholesterol levels and the outcomes of early statin use, large clinical trials should be conducted to further refine which patients would benefit from this strategy."
Currently, physicians routinely prescribe statins to heart attack patients at or shortly after discharge from the hospital if their levels of LDL-cholesterol, the so-called "bad" form of cholesterol, are 130 milligrams per deciliter (mg/dL) or greater. Statins have proven to reduce LDL-cholesterol levels from 20 percent to 60 percent and can even increase the levels of the so-called 'good' HDL-cholesterol. The Duke researchers wanted to determine whether there would be any additional benefit to giving statins sooner while patients were still in the hospital after a heart attack.
The scientists found no difference in the 90-day and one-year rates of subsequent death or heart attack between patients who received early statins and those who received no statins. Additionally, they found, that patients with cholesterol levels below the 130 mg/dL threshold showed increased rates of death and heart attack.
Statins work by slowing down the liver's production of cholesterol, high levels of which are implicated in atherosclerosis, a disease process that leads to clogging of the arteries. Typically, heart attack patients are given one of the five Food and Drug Administration-approved statins at the time of discharge or within months of discharge from the hospital as a preventative measure against future heart attacks.
For her analysis, Newby pooled and analyzed the data gathered from two related international trials -- SYMPHONY and 2nd SYMPHONY (Sibrafabin vs. aspirin to yield maximum protection from ischemic heart events post-acute coronary syndromes) that enrolled a total of 15,904 patients. While these trials were designed to compare the effectiveness of aspirin to a new class of drugs that dissolves blood clots, researchers at the 931 participating centers also collected data on each patient's medication history, including the use of statins.
After reviewing the data collected for these trials, Newby found that 12,365 patients were not taking statins prior to their heart attack. Of these patients, 3,952 received statins within three days of their heart attack, and the remaining 8,413 survived more than five days after their heart attack but did not receive statins.
"While we were unable to prove that early use of statins had any effect on mortality, one encouraging result was that 91 percent of the patients started on statins were still taking them 90 days later," Newby said. "Compliance is the key for success in using statins, because it can take awhile for the benefits to be seen. A compliance rate of 91 percent is really high."
In addition to their ability to lower LDL-cholesterol and increase HDL-cholesterol, statins appear to have other beneficial effects as well, Newby explained. Studies in animal models and in humans suggest that they may have properties that decrease inflammation, limit blood clotting and improve blood vessel function.
"While I don't think the results of this study are enough yet to change the practice patterns of cardiologists, I do believe that the results of a randomized clinical trial will be required to determine if earlier initiation of early stain use translates into earlier realization of benefit in preventing another heart attack," Newby said.
Both of the SYMPHONY trials were funded by F. Hoffmann-La Roche, Basel, Switzerland. Newby's analysis was supported by the Duke Clinical Research Institute.