To date, efforts also are ongoing to encourage patients to lose weight, but Go says Kaiser cannot produce data showing weight loss was significantly down. However, he says, that even in obese patients who have higher heart attack risks, methods to control blood pressure and lipid levels appear to be having an impact.
The report also is the first to note the influence of using a cardiac biomarker such as troponin to determine whether a person was having a heart attack, a test that may have increased sensitivity for capturing more patients, and in effect increased the number of heart attacks captured in the data. "Thus, the observed decreases in myocardial infarction since 20000 are even more striking" the authors wrote.
The Kaiser study received financial support from the Permanente Medical Group and from a Schering-Plough Future Leaders in Cardiovascular Medical Research Grant. Go's collaborating researchers, all of Kaiser Permanente, include Robert Yeh, MD; Stephen Sidney, MD, Malini Chandra, Michael Sorel, and Joseph Selby.
Heart disease is the biggest cause of U.S. mortality, with 631,636 in 2006.
In an accompanying Perspective article in the Journal, Jeremiah R. Brown, Ph.D., and Gerald T. O'Connor, of the Dartmouth Institute for Health Policy and Clinical Practice, wrote that the Kaiser paper demonstrates "the likely association between the increased use of statins, beta-blockers and angiotensin-converting-enzyme inhibitors or angiotensin-receptor blockers and a reduction in the rates of fatal and non-fatal heart attacks."
Go emphasizes that he and his colleagues who produced the report aren't absolutely sure that Kaiser's aggressive prevention efforts are responsible for the reductions in fatal and non-fatal heart attacks, although he believes that it must be partially responsible. "There are still unmeasured factors we aren't able to account for," such as inflammatory factors that could not be measured.
But, he said Kaiser is "in the process of analyzing through a collaboration, called the Cardiovascular Research Network, on trends documented within 15 participating health plans across the country. "We're looking to see if there are in fact similar trends during the same period of time," he says.
That project is funded by the National Heart Lung and Blood Institute.