Over half of seniors who start oral bisphosphonate therapy are exposed for 3 or more years: novel rolling window approach and patterns of use

Most adherence studies only consider treatment following a first prescription. Using an extended follow-up, we found that 60% of seniors starting oral bisphosphonate therapy were exposed for >= 3 years (48% for >= 5 years). Studies are needed to examine the benefits and harms of continuing bisphosphonate therapy beyond 3 years. Introduction The purpose of this study was to identify and describe patterns of long-term oral bisphosphonate use among seniors using a novel methodological approach that considers extended follow-up. Methods Among Ontarians aged 66 years or older, we identified subjects with a first dispensing of alendronate or risedronate between November 2000 and December 2016. We followed them until death or December 2019 to identify patients with >= 3 years of bisphosphonate use, defined as a proportion of days covered >= 80%, using 3-year rolling windows. We calculated the proportion of patients with long-term therapy (>= 3 years of use) using Kaplan-Meier estimates. We described patterns of long-term use and compared patient characteristics between patients with and without long-term therapy. Results We identified 260,784 eligible seniors initiating bisphosphonate therapy. Of these, 60% continued therapy >= 3 years (77% women), and 48% continued >= 5 years. Characteristics did not meaningfully differ between patients with or without long-term therapy. The median length of long-term therapy was 7.0 (IQR 5.1) years for women and 6.1 (IQR 4.3) years for men. Only 20% experienced a treatment gap before long-term therapy, yet 50% experienced a treatment gap of >= 120 days after a median 5.3 years of therapy. Eighty-one percent who returned to therapy following a treatment gap re-initiated an oral bisphosphonate, with 18% switching to denosumab. Conclusions Among seniors initiating oral bisphosphonates, we found that 60% receive at least 3 years of therapy when using an extended follow-up. Studies are needed to examine the benefits and harms of continuing bisphosphonate therapy beyond 3 years.

Automated summary

Most seniors starting oral bisphosphonate therapy were exposed for at least 3 years, with 48% continuing for 5 years. Studies are needed to further investigate the benefits and risks of continuing bisphosphonate therapy beyond the initial 3-year mark.