Once-monthly dosing: an effective step forward

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.

Persistence across weekly and monthly bisphosphonates: analysis of US retail pharmacy prescription refills

OBJECTIVE

Determine whether monthly dosing of bisphosphonates has an impact on persistence relative to weekly dosing.

METHODS

We used the IMS Longitudinal Prescription database of retail prescription records to study 165,955 women aged 50 years or older newly initiated on therapy between September and November 2005 with no bisphosphonate prescriptions in the prior 12 months. All patients were followed for 365 days from their initial prescription and were considered persistent until they had a refill gap greater than 30 days between the end of the day's supply of one prescription and the beginning of the next. Proportional-hazards regression models were executed to compare persistence across bisphosphonates. Persistence may be underestimated because of the following: (1) we had no information on the receipt of samples; (2) we had no information about refills at pharmacies that did not participate in the IMS prescription database, (3) switched patients were excluded; and (4) the cohort was limited to patients newly initiated on bisphosphonates.

RESULTS

Patients initiating on monthly ibandronate had a lower average persistence duration (98 days) than weekly alendronate (116 days) and risedronate (113 days) patients (p < 0.0001). Based on the proportional-hazards model, monthly ibandronate patients were 10% more likely to discontinue than alendronate patients (HR = 1.10, p < 0.0001). After removing the patients who failed to refill after their initial prescription, persistence beyond patients' first refill were similar across the three bisphosphonates.

CONCLUSIONS

Monthly dosing does not appear to be associated with improvements in patient persistence with oral bisphosphonates for patients newly initiated on bisphosphonates.

Therapeutic adherence to bisphosphonates

Therapeutic adherence of patients is a key factor of treatment success in clinical praxis, although it is often neglected. Several studies have shown that insufficient persistence and compliance cause differences in the efficiency of treatments in clinical studies and clinical praxis. A recent meta-analysis even showed a clear inverse relationship between therapeutic adherence and mortality. Factors influencing the adherence to treatment include explanations by the physician, characteristics of the disease, patient's attitudes, but also the therapeutic regime. Osteoporosis as a chronic disorder with relatively long asymptomatic initial course represents a major problem. In addition, the currently available therapeutic regimes are discomfortable and, thus, contribute to the low therapeutic adherence of the patient. One of the factors causing discomfort in bisphosphonates therapy is the frequency of application--once daily or once weekly. Several questionnaire-based studies have shown that patients clearly prefer the new alternative once monthly regime available for ibandronate. Although the efficiency of the drug is proven in large clinical trials, the effects of the once monthly regime itself on hard clinical end-points like mortality can only be analyzed in long-term follow-up studies.