Patterns of use for brand-name versus generic oral bisphosphonate drugs in Ontario over a 13-year period: a descriptive study

Self-sacrificial MOFs for ultra-long controlled release of bisphosphonate anti-osteoporotic drugs

Metal-bisphosphonates are self-sacrificial controlled delivery systems that achieve ultra-long release of anti-osteoporotic bisphosphonate drugs.

Time trends in oral bisphosphonate initiation in Ontario, Canada over 20 years reflect drug policy and healthcare delivery changes

Characteristics of patients starting oral bisphosphonate therapy changed over time, reflecting trends in osteoporosis management (e.g., new drugs to market), and general healthcare delivery (e.g., benzodiazepine use declined, statin use increased). When designing studies that examine osteoporosis drug effects, potential time-related biases must be considered.

INTRODUCTION

To describe the type of oral bisphosphonate initiated and characteristics of patients starting oral bisphosphonate therapy over time.

METHODS

We identified community-dwelling older adults (ages ≥ 66 years) initiating oral bisphosphonate therapy from April 1996 to March 2016 (1996 to 2015 fiscal years) using healthcare administrative data in Ontario. Patients with conditions other than osteoporosis that may impact bisphosphonate prescribing were excluded. The bisphosphonate initiated and patient characteristics were summarized by fiscal year and stratified by sex.

RESULTS

We identified 560,817 eligible patients (81% women). Most patients initiated cyclical etidronate from 1996 until 2005, and then weekly regimens became dominant. In 2008, risedronate became the main oral bisphosphonate (46% risedronate, 43% alendronate, 11% etidronate); with its use increasing after availability of monthly and delayed-release risedronate formulations. In 2015, 71% of patients started risedronate, 28% started alendronate, and less than 2% started etidronate. Characteristics of patients changed over time, reflecting changes in osteoporosis management and general healthcare delivery. Over time, a larger proportion of men (9% to 28%) and patients with diabetes (women 10% to 17%, men 14% to 22%) initiated therapy; benzodiazepine (women 22% to 13%, men 20% to 10%) and estrogen-based hormone replacement therapy (12% to 15% of women 1996-2002 to 3% since 2008) decreased, while statin use increased (women 15% to 39%, men 14% to 52%).

CONCLUSIONS

The characteristics of patients starting oral bisphosphonate therapy have changed over time. Consideration must be given to these time trends when designing studies that examine osteoporosis drug effects.

Effectiveness of Oral Bisphosphonates in Reducing Fracture Risk Among Oral Glucocorticoid Users: Three Matched Cohort Analyses

The benefit of oral bisphosphonates in reducing fracture risk in glucocorticoid-induced osteoporosis is controversial. We aimed to estimate the effectiveness of oral bisphosphonates in reducing fracture risk in a cohort of new chronic oral glucocorticoid users. We created three matched cohorts using health care administrative data from Ontario, Canada. We included residents aged 66 years and older initiating chronic oral glucocorticoids (≥450 mg prednisone equivalent and ≥2 glucocorticoid prescriptions within a 6-month window) between January 1998 and September 2014. Exposed patients were those who initiated an oral bisphosphonate (alendronate, etidronate, or risedronate) within the first 6 months of starting chronic oral glucocorticoid therapy. Exposed cohorts (3945 alendronate, 5825 risedronate, and 8464 etidronate) were each matched 1:1 to unexposed patients on glucocorticoid exposure, fracture risk factors, and propensity score. We examined incident hip (primary outcome), vertebral, forearm, and humerus fractures using Cox proportional hazard models. Alendronate (hazard ratio [HR] = 0.46, 95% confidence interval [CI] 0.25-0.80) and risedronate (HR = 0.58, 95% CI 0.36-0.90) were associated with reduced hip fracture risk. Alendronate (HR =  0.52, 95% CI 0.39-0.68), etidronate (HR = 0.59, 95% CI 0.48-0.73) and risedronate (HR = 0.47 95% CI 0.36-0.60) were associated with reduced vertebral fracture risk. No risk reduction in forearm or humerus fractures was apparent for any bisphosphonate. Among older chronic glucocorticoid initiators, all oral bisphosphonates reduced vertebral fracture risk, yet only alendronate and risedronate reduced hip fracture risk. Results were similar between men and women. We provided compelling evidence that early initiation of oral bisphosphonates during chronic oral glucocorticoid therapy is beneficial to prevent osteoporotic fractures. © 2017 American Society for Bone and Mineral Research.

Brand and generic use of inhalation medication and frequency of switching in children and adults: A population-based cohort study

BACKGROUND

The expiration of patents of brand inhalation medications and the ongoing pressure on healthcare budgets resulted in a growing market for generics.

AIM

To study the use of brand and generic inhalation medication and the frequency of switching between brand and generic and between devices. In addition, we investigated whether switching affected adherence.

METHODS

From dispensing data from the Dutch PHARMO Database Network a cohort aged ≥ 5 years, using ≥ 1 year of inhalation medication between 2003 and 2012 was selected. Switching was defined as changing from brand to generic or vice versa. In addition, we studied change in aerosol delivery device type (e.g., DPI, pMDI, and nebulizers). Adherence was calculated using the medication possession ratio (MPR).

RESULTS

The total cohort comprised 70,053 patients with 1,604,488 dispensations. Per calendar year, 5% switched between brand and generic inhalation medication and 5% switched between devices. Median MPRs over the first 12 months ranged between 33 and 55%. Median MPR over the total period was lower after switch from brand to generic and vice versa for formoterol (44.5 vs. 42.1 and 63.5 vs. 53.8) and beclomethasone (93.8 vs. 59.8 and 81.3 vs. 55.9).

CONCLUSION

Per year, switching between brand and generic inhalation medication was limited to 5% of the patients, switching between device types was observed in 5% as well. Adherence to both generic and brand inhalation medication was low. Effect of switching on adherence was contradictory; depending on time period, medication and type, and direction of switching. Further research on reasons for switching and potential impact on clinical outcomes is warranted.

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

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.