Study Compares Cardiovascular Events, Stroke in Patients Prescribed Beta-Blockers for Hypertension

CHICAGO – A study that compared the incidence of myocardial infarction (MI, heart attack), stroke and heart failure in patients with hypertension who were newly prescribed two β (beta)-blocker drugs suggests there were no significant differences in cardiovascular events between patients who took atenolol or metoprolol tartrate, according to a report published Online First by Archives of Internal Medicine, a JAMA Network publication. Randomized controlled trials have shown selected β-blockers to be effective for preventing cardiovascular (CV) events in patients after MI or with heart failure (HF), but the effectiveness of the medications for preventing CV events in patients with hypertension has been questioned, although it is unclear whether that applies to the entire β-blocker class. Two large clinical trials have suggested that atenolol-based regimens were less effective than other antihypertensive drugs for preventing CV events in patients with hypertension, according to the study background. Emily D. Parker, M.P.H., Ph.D., of HealthPartners Institute for Education and Research, Minneapolis, Minn., and colleagues used electronic medical record and health data from the Cardiovascular Research Network Hypertension Registry (which includes patients from three large integrated health care delivery systems in Minnesota, Colorado and California) to compare the occurrence of MI, HF and stroke in patients who were new β-blocker users between 2000 and 2009. A total of 120,978 patients without a history of cardiovascular disease (CVD) events started treatment. Atenolol was used by approximately 10 times more patients than metoprolol tartrate, according to study results. “In this retrospective cohort study comparing patients initiating β-blocker treatment with either atenolol or metoprolol tartrate, there were no statistically significant differences in rates of incident MI, HF or stroke after adjusting for potential confounders,” the authors comment. During follow-up (median 5.2 years), there were 3,517 incident MIs, 3,272 HF hospitalizations and 3,664 incident strokes. Hazard ratios for MI, HF and stroke in metoprolol tartrate users were 0.99 for each, respectively, the results indicate. “In conclusion, we found no differences in CV event rates when comparing patients without a history of CV events who were initiating treatment with either atenolol or metoprolol tartrate,” the authors conclude. “These findings suggest that hypertension trial outcomes with atenolol may not relate to unfavorable characteristics of this particular drug. These results should be interpreted cautiously, since there have been no trials comparing these two β-blockers directly.” (Arch Intern Med. Published online August 27, 2012. doi:10.1001/archinternmed.2012.4276.) Editor’s Note: The project was funded by a grant from the National Heart, Lung and Blood Institute and subcontract to HealthPartners Institute for Education and Research. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.