Urban-rural differences in the uptake of new oral bisphosphonate formulations

Abstract

We identified significantly slower uptake, and consistently lower proportions of new oral bisphosphonate formulations dispensed in rural regions compared to urban regions of Ontario. Further research examining regional differences in outcomes may provide insight as to whether urban-rural differences in prescribing translate into health disparities between regions.

Purpose: The aim of this study was to examine urban-rural differences in the uptake of new oral bisphosphonate formulations available on the Ontario drug formulary: alendronate + vitamin D3 (January 2007), monthly risedronate (June 2009), and risedronate delayed-release (February 2012).

Methods: We plotted the monthly proportion of new formulation claims of all claims with the same drug molecule, from their formulary listing date until March 2014. Results were stratified by major urban, nonmajor urban, and rural regions as defined by the Rurality Index of Ontario. We compared the rate of uptake over the first year of formulary availability using linear regression, and compared proportions dispensed between regions using chi-squared tests.

Results: We identified a regional gradient in uptake for alendronate + vitamin D3 and monthly risedronate; major urban regions had the fastest uptake, followed by nonmajor urban regions, and rural regions had the slowest uptake. Rural regions also had the slowest uptake of risedronate delayed-release; however, uptake in major urban and nonmajor urban regions were similar. Rural regions dispensed the lowest proportions for all new formulations 1 year after formulary availability: alendronate + vitamin D3 (32% major urban, 23% nonmajor urban, 12% rural), monthly risedronate (26% major urban, 21% nonmajor urban, 16% rural), and risedronate delayed-release (21% major urban, 22 % nonmajor urban, 13% rural). This pattern persisted throughout our study.

Conclusion: We identified significantly slower uptake and lower proportions of new formulations dispensed in rural regions compared to urban regions. Further research examining regional differences in outcomes may demonstrate whether urban-rural differences in prescribing translate into health disparities between regions.

Keywords: Drug utilization; Oral bisphosphonates; Osteoporosis treatment; Urban–rural health.