Rural-Urban Trends in Beta-3 Agonist Prescribing Patterns, 2013-2021

Objectives: The impact of anticholinergic medications on cognitive function in older adults has emerged over the last decade. While prior studies have examined prescription trends for antimuscarinics and their alternative, beta-3 agonists for overactive bladder (OAB), none include data incorporating the newest beta-3 agonist, Vibegron, approved for U.S. markets in December 2020. While some studies have described prescription rates by specialty and region, we sought to assess the interplay of these factors with urban-rural status.

Methods: Using Medicare Part D Prescribers data, we identified all outpatient pharmacy claims for anti-muscarinic and beta-3 agonist medications used to treat OAB between 2013-2021. Prescriber location was used to associate each claim with urban-rural status, using the National Center for Health Statistics Urban-Rural Classification Scheme. Provider region and specialty were also identified. Proportions of beta-3 agonists among all OAB medication claims were plotted over time. To compare overall trends, Z-tests with Bonferroni correction were used to compare the regression line fit to each group. For each comparator group, the difference in beta-agonist prescription rate from the overall rate was examined.

Results: From 2013-2021, beta-3 agonist claims increased from 64,500 to 1.44 million (1.6% to 36% of total OAB medication claims, respectively). While this upward trend was seen across all regions, the Midwest had the lowest rate of increase (P < 0.008, Figure 1). Large central metro areas had a significantly higher rate of increase than all other metro areas (large fringe, small, micropolitan/non-core) with the exception of medium metro areas. OBGYN and Geriatrics had greater rates of increase than all other specialties (p < 0.005).

Most rural areas lagged increasingly behind the average national prescribing rate over time (Fig 2). When controlling for region, the gap between the most rural and most urban counties persists, most clearly demonstrated in the Northeast and Midwest. Excluding the South, the fastest increase in this gap occurred over the most recent 3 years of data.

Family Medicine and Internal Medicine accounted for over 80% of all prescriptions in the most rural counties versus over 60% for all other counties; however, they were also persistently below national prescribing rates across every urban category for nearly every year since 2013. When controlling for specialty, differences in the most rural and urban counties were moderately preserved amongst all specialties except family medicine.

Figure 1. Share of beta-3 agonist prescriptions by region, urbanicity, and specialty
Figure 2. Difference between national rate of beta-3 agonist prescriptions and categories of urbanicity, stratified by region

Conclusions: Our study suggests that the most rural regions would benefit from educational interventions on beta-3 agonists for OAB, regardless of region and specialty. There was a notable increase in beta-agonist prescriptions by OBGYNs following the AUGS statement on anticholinergic use in 2018.