They included Fernie Penning-van Beest, PhD, of the Pharmo Institute, located in Utrecht, Netherlands. The institute's clients include drug companies.
"Drugs are only really effective if they are used properly and persistently," Penning-van Beest says in a news release.
The study is scheduled to appear in the European Heart Journal's Dec. 7 edition.
Data came from the Pharmo Institute's records on more than 59,000 Dutch patients who were prescribed statin drugs between 1991 and 2004.
More than half of the patients (53%) stopped using statins within the first two years of statin treatment, the study shows.
Those patients were 30% more likely to be hospitalized for a heart attack during the study period than those who kept taking statin drugs.
Based on those numbers, the researchers estimate that "persistent, high-dose" statin treatment can prevent 300-400 heart attacks per year among statin users in the Netherlands.
For instance, the data don't show whether the patients who quit taking statins also quit taking other drugs, or why they stopped taking statins.
The study was funded by Nefarma, a Dutch pharmaceutical association.