Original ArticlesAntibiotic Use in Cold and Flu Season and Prescribing Quality A Retrospective Cohort StudyAlsan, Marcella MD, MPH, PhD*,†; Morden, Nancy E. MD, MPH‡,§; Gottlieb, Joshua D. PhD†,∥; Zhou, Weiping MS‡; Skinner, Jonathan PhD†,‡,§,¶ Author Information *Center for Health Policy and the Center for Primary Care and Outcomes Research, Stanford University, Stanford, CA †National Bureau of Economic Research, Cambridge, MA ‡Dartmouth Institute for Health Policy and Clinical Practice, Lebanon, NH §Department of Community and Family Medicine, Geisel School of Medicine at Dartmouth, Hanover, NH ∥Vancouver School of Economics, University of British Columbia, Vancouver, BC, Canada ¶Department of Economics, Dartmouth College, Hanover, NH Supplemental Digital Content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Website, www.lww-medicalcare.com. Supported by the National Institutes of Aging (P01-AG019783). Additional funding from the National Institutes of Health Common Fund (U01-AG046830). J.S. is an investor in Dorsata Inc., a startup clinical pathway software company. The remaining authors declare no conflict of interest. Reprints: Marcella Alsan, MD, MPH, PhD, Stanford University School of Medicine, 117 Encina Commons, Stanford, CA 94305. E-mail: [email protected]. Medical Care: December 2015 - Volume 53 - Issue 12 - p 1066-1071 doi: 10.1097/MLR.0000000000000440 Buy SDC Metrics Abstract Background: Excessive antibiotic use in cold and flu season is costly and contributes to antibiotic resistance. The study objective was to develop an index of excessive antibiotic use in cold and flu season and determine its correlation with other indicators of prescribing quality. Methods and Findings: We included Medicare beneficiaries in the 40% random sample denominator file continuously enrolled in fee-for-service benefits for 2010 or 2011 (7,961,201 person-years) and extracted data on prescription fills for oral antibiotics that treat respiratory pathogens. We collapsed the data to the state level so they could be merged with monthly flu activity data from the Centers for Disease Control and Prevention. Linear regression, adjusted for state-specific mean antibiotic use and demographic characteristics, was used to estimate how antibiotic prescribing responded to state-specific flu activity. Flu-activity associated antibiotic use varied substantially across states—lowest in Vermont and Connecticut, highest in Mississippi and Florida. There was a robust positive correlation between flu-activity associated prescribing and use of medications that often cause adverse events in the elderly (0.755; P<0.001), whereas there was a strong negative correlation with beta-blocker use after a myocardial infarction (−0.413; P=0.003). Conclusions: Adjusted flu-activity associated antibiotic use was positively correlated with prescribing high-risk medications to the elderly and negatively correlated with beta-blocker use after myocardial infarction. These findings suggest that excessive antibiotic use reflects low-quality prescribing. They imply that practice and policy solutions should go beyond narrow, antibiotic specific, approaches to encourage evidence-based prescribing for the elderly Medicare population. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.