Trends in off-label β-blocker use: A secondary data analysis

Abstract

Background: The off-label use of β-blockers might be prevalent, but no studies have provided empiric data on the off-label use based on utilization data. Objective: This secondary data analysis was conducted to describe the trends of off-label use of β-blockers among ambulatory visits made to office-based physicians in the United States. Methods: Data from the National Ambulatory Medical Care Surveys from 1999 to 2002 were used in this study. Physician visits at which β-blockers were prescribed ( β-blocker visits) were included and classified as within-label or off-label visits according to whether an approved indication for the β-blocker was coded for the visits. Variables of patient demographic characteristics, diagnosis, prescriber's specialty, and concomitant medication use were also analyzed. Logistic regression analysis was employed to investigate the potential determinants for the off-label use of β-blockers. Results: A total of 3349 million visits were made to office-based physicians during the study period. About 65% (2167 million) of all visits were prescribed with ≥1 medication ( medication visits). β-Blockers were prescribed in 5.9% (127.3 million) of all medication visits in the years 1999 to 2002. The 3 most frequently prescribed β-blockers in this study were atenolol, metoprolol, and propranolol. The proportions of off-label use among β-blocker visits were 44.3% (1999), 56.3% (2000), 62.3% (2001), and 46.9% (2002); overall, 52.0% (66.2 million). About 11% (75.7 million) of these off-label uses were prescribed to patients with concomitant conditions that required judicious use of β-blockers. Specialists, such as cardiologists, were more likely to prescribe β-blockers for off-label use than primary care physicians (odds ratio, 2.147; 95% CI, 2.1464–2.1473). Conclusions: Our study found that the off-label use rate of β-blockers was higher than what has been previously reported for other diseases and medications. Compared with visits made to general practitioners, visits made to specialists were more likely to be prescribed off-label use of β-blockers. Future studies are needed to understand the legal, economic, and clinical impact of off-label use.