Polypharmacy prevalence in older adults seen in United States physician offices from 2009 to 2016

Abstract

Background/objectives: With an aging population suffering from increased prevalence of chronic conditions in the United States (U.S.), a large portion of these patients are on multiple medications. High-risk medications can increase the risk for drug-drug interactions and medication nonadherence. This study aims to describe the prevalence of polypharmacy and high-risk medication prescribing in U.S. physician offices.

Methods: This was a cross-sectional study of the Centers for Disease Control and Prevention's National Ambulatory Medical Care Survey from 2009 to 2016. All patients over 65 years old were included. Polypharmacy was categorized as no polypharmacy (< 2 medications), minor polypharmacy (2-3 medications), moderate polypharmacy (4-5 medications), and major polypharmacy (>5 medications). Medications were further categorized into high-risk medication categories (anticholinergics, cardiovascular agents, central nervous system (CNS) medications, pain medications, and other). Comparisons between the degrees of polypharmacy were performed utilizing chi-square or Wilcoxon rank-sum tests with JMP Pro 14® (SAS Institute, Cary, NC).

Results: Over 2 billion patient visits were included. Overall, Polypharmacy was common (65.1%): minor polypharmacy (16.2%), moderate polypharmacy (12.1%), and major polypharmacy (36.8%). Patients with major polypharmacy were older compared to those with moderate or minor polypharmacy (75 vs. 73 years, respectively) and were most frequently prescribed pain medications (477.3 per 1,000 total visits). NSAIDs were the most frequently prescribed, with 232.4 per 1,000 total visits resulting in one high-risk NSAID prescription, while 21.9 per 1,000 total visits resulted in two or more high-risk NSAIDs.

Conclusion: Most patients over 65 years experienced some degree of polypharmacy, with many experiencing major polypharmacy. This indicates an increased need for expanded pharmacist roles through medication therapy management and safety monitoring in this patient population.

Fig 1. High-risk medication prescription rates by medication category.

⁺ All comparisons between no polypharmacy vs. minor polypharmacy vs. moderate polypharmacy vs. major polypharmacy groups were deemed statistically significant (p<0.0001).

Fig 2. Rate of patients prescribed at least one high-risk medication overall and by medication class.

⁺ All comparisons between one medication and two or more medications were deemed statistically significant (p<0.0001).